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  • 1995-1999  (18,930)
  • Polymer and Materials Science  (14,995)
  • Engineering  (2,961)
  • Computational Chemistry and Molecular Modeling  (973)
  • Nuclear reactions
Source
Material
Years
Year
Keywords
  • 101
    Electronic Resource
    Electronic Resource
    Integro-differential equation modelling heat transfer in conducting, radiating and semitransparent materials (1998)
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 21 (1998), S. 375-392 
    Details
    ISSN: 0170-4214
    Keywords: Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In this work we analyse a model for radiative heat transfer in materials that are conductive, grey and semitransparent. Such materials are for example glass, silicon, water and several gases. The most important feature of the model is the non-local interaction due to exchange of radiation. This, together with non-linearity arising from the well-known Stefan-Boltzmann law, makes the resulting heat equation non-monotone. By analysing the terms related to heat radiation we prove that the operator defining the problem is pseudomonotone. Hence, we can prove the existence of weak solution in the cases where coercivity can be obtained. In the general case, we prove the solvability of the system using the technique of sub and supersolutions. © 1998 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Additional Material: 2 Ill.
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  • 102
    Electronic Resource
    Electronic Resource
    Control of the thermoelastic model of a plate activated by shape memory alloy reinforcements (1998)
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 21 (1998), S. 589-603 
    Details
    ISSN: 0170-4214
    Keywords: Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In the paper we study the problem of control by means of a heat source g for a thermoelastic system of equationsutt - ρ∇·p(θ, ∇u) - νΔut + DΔ2 u = f, cv(θ, ∇u)θt - κΔθ - ρθ[pθ (θ, ∇u)·∇ut] - ν∣∇ut∣2 = g, in a two-dimensional domain, where both viscosity ν and rigidity D are positive. Such a system has been considered in our former papers, and existence of solutions as well as uniqueness have been obtained. Here we prove the continuity and differentiability of solutions under somewhat stronger assumptions. An example of a control problem and necessary optimality conditions are presented. The system has an interpretation as a plate reinforced with shape memory alloy (SMA) wire mesh. © 1998 B. G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Additional Material: 2 Ill.
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  • 103
    Electronic Resource
    Electronic Resource
    Bäcklund transformations: exact solutions for the KdV and the Calogero-Degasperis-Fokas mKdV equations (1998)
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 21 (1998), S. 719-731 
    Details
    ISSN: 0170-4214
    Keywords: Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The exact solutions for the KdV and the Calogero-Degasperis-Fokas mKdV equations can be obtained by the AKNS class. The technique developed relies on the construction of the wave functions which are solutions of the associated AKNS system; that is, a linear eigenvalue problem in the form of a system of first order partial differential equations. The method of characteristics is used and Bäcklund transformations (BTs) are employed to generate two new solutions from the old. © 1998 B.G. Teubner Stuttgart-John Wiley & Sons Ltd.
    Type of Medium: Electronic Resource
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  • 104
    Electronic Resource
    Electronic Resource
    On the existence of a global classical solution of the boundary value problem for □u-μu+aum=0 in the interior domain (1998)
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 21 (1998), S. 781-795 
    Details
    ISSN: 0170-4214
    Keywords: Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In this paper we consider the boundary value problem for a semilinear equation□u(t, x)-μu(t, x)+aum(t, x)=0, μ〉0, a∊ℜ in the interior domain. We find a time global classical solution with exponential decay property by using singular hyperbolic equation. © 1998 B. G. Teubner Stuttgart - John Wiley & Sons, Ltd.
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  • 105
    Electronic Resource
    Electronic Resource
    On the inverse emergent plane crack problem (1998)
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 21 (1998), S. 895-906 
    Details
    ISSN: 0170-4214
    Keywords: geometrical inverse problems ; crack detection ; identifiability ; stability ; Lipschitz stability ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: This paper deals with the detection of emergent plane cracks, by using boundary measurements. An identifiability result (uniqueness of the solution) is first proved. Then, we look at the stability of this solution with respect to the measurement. A weak stability result is proved, as well as a Lipshitz stability result for straight cracks, by using domain-derivative techniques. © 1998 B. G. Teubner Stuttgart - John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
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  • 106
    Electronic Resource
    Electronic Resource
    Existence and non-existence of global solutions to a generalized modification of the improved Boussinesq equation (1998)
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 21 (1998), S. 1467-1477 
    Details
    ISSN: 0170-4214
    Keywords: Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In this paper, the existence, both locally and globally in time, the uniqueness of solutions and the non-existence of global solutions to the initial boundary value problem of a generalized Modification of the Improved Boussinesq equation utt-uxx-uxxtt=σ(u)xx are studied and a few examples are discussed. © 1998 B. G. Teubner Stuttgart - John Wiley & Sons, Ltd.
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  • 107
    Electronic Resource
    Electronic Resource
    Reaction diffusion equations with non-linear boundary conditions, blowup and steady states (1998)
    Chichester, West Sussex : Wiley-Blackwell
    Mathematical Methods in the Applied Sciences 21 (1998), S. 1593-1617 
    Details
    ISSN: 0170-4214
    Keywords: Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In this paper we study the following problem:ut-Δu=-f(u) in Ω×(0, T)≡QT,∂u ∂n=g(u) on ∂Ω×(0, T)≡ST,u(x, 0)=u0(x) in Ω, where Ω⊂∝N is a smooth bounded domain, f and g are smooth functions which are positive when the argument is positive, and u0(x)〉0 satisfies some smooth and compatibility conditions to guarantee the classical solution u(x, t) exists. We first obtain some existence and non-existence results for the corresponding elliptic problems. Then, we establish certain conditions for a finite time blow-up and global boundedness of the solutions of the time-dependent problem. Further, we analyse systems with same kind of boundary conditions and find some blow-up results. In the last section, we study the corresponding elliptic problems in one-dimensional domain. Our main method is the comparison principle and the construction of special forms of upper-lower solutions using related equations. © 1998 B. G. Teubner Stuttgart - John Wiley & Sons, Ltd.
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  • 108
    Electronic Resource
    Electronic Resource
    Kinetics of the photoinitiated inverse microemulsion polymerization of 2-methacryloyl oxyethyl trimethyl ammonium chloride (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 737-748 
    Details
    ISSN: 0887-624X
    Keywords: inverse microemulsion polymerization ; MADQUAT ; nucleation ; photopolymerization ; molecular weights ; flocculants ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of inverse microemulsions of 2-methacryloyl oxyethyl trimethyl ammonium chloride stabilized by a blend of nonionic emulsifiers (a sorbitan sesquioleate and a sorbitan monooleate) and initiated by UV light in the presence of Azobis(isobutyronitrile) (AIBN) was investigated. The effect of initiator concentration, light intensity, emulsifier concentration, and dispersed phase weight fraction on the polymerization rate (Rp), number of polymer particles (Np), and polymer molecular weight (Mw) was studied. The application of this process to tubular reactors is discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 737-748, 1998
    Additional Material: 15 Ill.
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  • 109
    Electronic Resource
    Electronic Resource
    Ionic and excited intermediates in pulse-irradiated polypropylene doped with aromatics (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1217-1226 
    Details
    ISSN: 0887-624X
    Keywords: polypropylene ; pyrene ; two-solute system ; pulse radiolysis ; solute ionic species ; solute excited states ; low-temperature radiolysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A pulse radiolysis study of isotactic polypropylene (PP) film has been carried out with the main aims of investigating charge trapping in an undoped system and solute radical ion generation in an pyrene (Py) doped matrix. In PP, pulse radiolysis gives electron-positive hole pairs. The electron can be stabilized in the undoped system as a trapped electron, et-. The transient absorption spectrum of et- in the near-IR (up to 1800 nm) was observed in the temperature range 30-100 K. This IR absorption was not detected in the case of oxidized PP. In such a matrix electrons can be scavenged by oxidation products generating respective radical-anions (absorption in the UV RANGE, λ 〈 350 nm). In a doped matrix transient absorption bands centered at 450 and 500 nm were observed which can be assigned to the Py radical cation and anion, respectively. The recombination of these ionic species leads to monomer excited-state formation observed during and after the 17 ns pulse. Contrary to the Py-doped polyethylene no excimer emission was detected at room temperature even if Py content in PP was close to 0.02 mol dm-3. The rate of Py radical-ion decay was found to be temperature dependent. Two linear parts of the Arrhenius plot were observed which intersected at ca. 240 K, the glass transition temperature, Tg, for PP. The activation energies calculated for two parts of Arrhenius plot were equal to 111 and ca. 0.78 kJ mol-1 for T 〉 Tg and T 〈 Tg, respectively. Some preliminary results concerning the ionic processes in PP containing two solutes (Py, 3,3′-dimethyldiphenyl) were presented. The mechanism of ionic recombination in PP will be proposed and discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1217-1226, 1998
    Additional Material: 7 Ill.
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  • 110
    Electronic Resource
    Electronic Resource
    Synthesis of acid-functional asymmetric aliphatic polyesters (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1345-1348 
    Details
    ISSN: 0887-624X
    Keywords: acid functional ; telechelic ; benzyl alcohol ; poly(ε-caprolactone) ; polymerization ; living ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 111
    Electronic Resource
    Electronic Resource
    Enzymatic activity of trypsin adsorbed on temperature-sensitive composite polymer particles (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 883-888 
    Details
    ISSN: 0887-624X
    Keywords: temperature sensitive ; particle ; emulsion polymerization ; morphology ; adsorption ; enzyme ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two kinds of temperature-sensitive composite polymer particles were prepared by seeded emulsion copolymerizations of (dimethylamino)ethyl methacrylate and ethylene glycol dimethacrylate with 0.14 μm-sized polystyrene and 0.26 μm-sized poly(methylmethacrylate) seed particles. To evaluate the usefulness as a carrier for biomolecules, the enzymatic activities of trypsin adsorbed on these two composite polymer particles were measured at temperatures above and below each lower critical solution temperature (LCST). In both cases, adsorbed trypsin retained its enzymatic activity during repeated adsorption/desorption measurements. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 883-888, 1998
    Additional Material: 7 Ill.
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  • 112
    Electronic Resource
    Electronic Resource
    Synthesis of (1→6)-2,5-anhydro-D-glucitol through cyclopolymerization of 3,4-di-O-allyl-1,2 : 5,6-dianhydro-D-mannitol and optical resolution ability of its derivative in HPLC (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 901-909 
    Details
    ISSN: 0887-624X
    Keywords: (1→6)-2,5-anhydro-D-glucitol ; HPLC ; optical resolution ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cyclopolymerization of 3,4-di-O-allyl-1,2 : 5,6-dianhydro-D-mannitol (1) was carried out using BF3·OEt2 and t-BuOK. The polymer obtained by the polymerization with BF3·OEt2 mainly consisted of (1→6)-bonded 3,4-di-O-allyl-2,5-anhydro-D-glucitol as the five-membered constitutional repeating unit, though it contained a small amount of other cyclic repeating units. On the other hand, during the polymerization using t-BuOK, the stereoregular polymer (1→6)-linked 3,4-di-O-allyl-2,5-anhydro-D-glucitol (2) was synthesized via a regio- and stereoselective mechanism. Cleavage of the allyl ether linkage in polymer 2 occurred to produce the polymer consisting of only 2,5-anhydro-D-glucitol units, i.e., (1→6)-2,5-anhydro-D-glucitol (3). Chromatographic enantioseparation of chloroquine and tröger base has been performed on (3,5-dimethylphenyl)carbamate and 4-methylbenzoate derivatives of 3 as a chiral stationary phase for high-performance liquid chromatography. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 901-909, 1998
    Additional Material: 4 Ill.
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  • 113
    Electronic Resource
    Electronic Resource
    Model structures of thermoplastic polyesters having regularly alternated aromatic and fluorinated segments (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 939-947 
    Details
    ISSN: 0887-624X
    Keywords: fluorine ; perfluoropolyether ; polyester ; segmented ; thermoplastic ; interfacial synthesis ; thermal transitions ; dynamic-mechanical properties ; chemical resistance ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Linear segmented polyesters containing soft perfluoropolyether (PFPE) and hard aromatic segments are obtained by an interfacial polycondensation reaction of an acyl chloride-ended fluorinated prepolymer with various aromatic diphenols in the presence of phase transfer catalysts (PTC) as accelerators. Experimental conditions for reaching high molecular weights are discussed. The calorimetric analysis (DSC) of all the polyesters synthesized shows a typical biphasic morphology, where a very low Tg (〈 -110°C) corresponding to the segregated PFPE moiety, is always accompanied by another Tg or a higher melting temperature, depending on the nature of the hard phase. Dynamic-mechanical analysis (DMA) has been carried out confirming the DSC results and suggesting diversified mechanical behaviors at the various temperatures in line with the amorphous or semicrystalline nature of the polymer. Chemical resistance was finally tested by dipping in several solvents and chemicals. The new polyesters show high contact angles, a moderate swelling in many organic solvents and excellent stability in aggressive hydrolytic environments. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 939-947, 1998
    Additional Material: 6 Ill.
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  • 114
    Electronic Resource
    Electronic Resource
    Kinetics and mechanisms of emulsion polymerization of vinylidene chloride. I. Effects of operating variables on the rate of polymerization and the number of polymer particles produced (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1919-1928 
    Details
    ISSN: 0887-624X
    Keywords: emulsion polymerization ; vinylidene chloride ; kinetics ; sodium lauryl sulfate ; potassium persulfate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Emulsion polymerization of vinylidene chloride was carried out at 50°C using sodium lauryl sulfate as emulsifier and potassium persulfate as initiator, respectively. Contrary to the results so far reported, the stirring rate did not affect the progress of the polymerization and such an abnormal kinetic behavior as the rate of polymerization suddenly drops in the course of polymerization was not observed. The number of polymer particles produced was proportional to the 0.7 power of the concentration of emulsifier forming micelles and to the 0.3 power of the initial initiator concentration, respectively, and was independent of the initial monomer concentration. The rate of polymerization was in proportion to the 0.3 power of the concentration of emulsifier forming micelles, to the 0.5 power of the initial initiator concentration, to the 0.2 power of the initial monomer concentration, and to the 0.45 power of the number of polymer particles, respectively. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1919-1928, 1998
    Additional Material: 13 Ill.
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  • 115
    Electronic Resource
    Electronic Resource
    A polyimide precursor solution based on a novel concept (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1961-1964 
    Details
    ISSN: 0887-624X
    Keywords: Poly(4,4′-phenylene-3,3′,4,4′-biphenyltetracarboxyimide) ; poly(4,4′-oxydiphenylenepyromellitimide) ; precursor solution ; aprotic polar solvent ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
    Additional Material: 4 Ill.
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  • 116
    Electronic Resource
    Electronic Resource
    Hydrosilation routes to materials with high thermal and oxidative stabilities (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1969-1972 
    Details
    ISSN: 0887-624X
    Keywords: hydrosilation ; polymer ; siloxane ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
    Additional Material: 2 Ill.
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  • 117
    Electronic Resource
    Electronic Resource
    Covalent modification in aqueous solution of poly-γ-D-glutamic acid from bacillus licheniformis (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1995-1999 
    Details
    ISSN: 0887-624X
    Keywords: poly-γ-D-glutamic acid ; biopolymer ; covalent modification ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methods for the covalent modification in aqueous solution of poly-γ-D-glutamic acid from Bacillus licheniformis have been studied. Co-derivatization of a synthetic UV-absorbent amine and ethanolamine, using a water-soluble carbodi-imide coupling agent, yielded a water-soluble modified polymer. Derivatization of the polymer was accompanied by cleavage of the γ-linked polypeptide backbone, and a reduction in molecular mass from 170 to 10 kDa. A procedure was developed for the removal of noncovalently bound ligands by treatment with 5 M CaCl2. The polymer sidechains also reacted in aqueous solution with p-nitrophenyl acetate to form covalent linkages. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 1995-1999, 1998
    Additional Material: 4 Ill.
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  • 118
    Electronic Resource
    Electronic Resource
    Synthesis and radical ring-opening polymerization of vinylcyclopropanes bearing vinylsilane groups (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2037-2042 
    Details
    ISSN: 0887-624X
    Keywords: radical polymerization ; vinylcyclopropane ; vinylsilane ; desilylation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and radical polymerization of novel vinylcyclopropanes; 1-carboethoxy-2-trimethylsilyl-2-vinylcyclopropane (1a) and 1-carboethoxy-2-(1-trimethylsilyl)-vinylcyclopropane (1b), were examined. 1a and 1b were prepared by the coupling reaction of 2-trimethylsilylbutadiene with ethyl diazoacetate, which was prepared from glycine ethyl ester hydrochloride. The radical polymerization of 1a and 1b was carried out at 60°C in bulk for 40 h in the presence of 2,2′-azobis(isobutyronitrile) (5 mol % vs. monomer). Poly(1) consisted of a 1,5-ring-opened unit. Desilylation reaction of poly(1) proceeded quantitatively in aqueous hydrochloric acid. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2037-2042, 1998
    Additional Material: 1 Ill.
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  • 119
    Electronic Resource
    Electronic Resource
    Preparation and properties of new soluble aromatic polyimides from 2,2′-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride and aromatic diamines (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2021-2027 
    Details
    ISSN: 0887-624X
    Keywords: 2,2′-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride ; aromatic polyimides ; solubility ; thermal behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new aromatic tetracarboxylic dianhydride having a crank and twisted noncoplannar structure, 2,2′-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, was synthesized by the reaction of 4-nitrophthalonitrile with biphenyl-2,2′-diol, followed by hydrolysis and cyclodehydration. The biphenyl-2,2′-diyl-containing aromatic polyimides having inherent viscosities up to 0.66 dL/g were obtained by the conventional two-step procedure starting from the dianhydride monomer and various aromatic diamines. Most of the polyimides were readily soluble in amide-type solvents such as N,N-dimethylacetamide and N-methyl-2-pyrrolidone. The aromatic polyimides had glass transition temperatures in the range of 205-242°C, and began to lose weight around 415°C, with 10% weight loss being recorded at about 500°C in air. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2021-2027, 1998
    Additional Material: 2 Ill.
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  • 120
    Electronic Resource
    Electronic Resource
    Studies of lipase-catalyzed polyesterification of an unactivated diacid/diol system (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2069-2079 
    Details
    ISSN: 0887-624X
    Keywords: Candida antarctica lipase ; Novozym 435® ; polyester ; enzymatic polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preliminary enzymatic polymerization studies in the simple stoichiometric adipic acid/butane-1,4-diol system using lipase B from Candida antarctica, immobilized as Novozym 435®, suggest that in solvent-free conditions a step-growth mechanism operates involving the sequential addition of an AB synthon by esterification mode only. Conversely, in toluene as solvent there is a change to the more facile transesterification mode in line with the conventional polyesterification procedure, pointing to a change in specificity of the lipase. Evidence is drawn from qualitative studies using a series of synthetic intermediates, enabling authentication of product mixtures together with an indication of the comparative reactivity of species along the proposed reaction pathway. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2069-2080, 1998
    Additional Material: 5 Ill.
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  • 121
    Electronic Resource
    Electronic Resource
    Mechanical properties of blends of PAMAM dendrimers with poly(vinyl chloride) and poly(vinyl acetate) (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2111-2117 
    Details
    ISSN: 0887-624X
    Keywords: dendritic polymer ; blends ; coatings ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hybrid blends of poly(amidoamine) PAMAM dendrimers with two linear high polymers, poly(vinyl chloride), PVC, and poly(vinyl acetate), PVAc, are reported. The interaction between the blend components was studied using dynamic mechanical analysis, xenon nuclear magnetic resonance (NMR) spectroscopy, and tensile property measurements. The data suggest a much higher degree of interaction between components of PVAc-containing blends compared to those containing PVC. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2111-2117, 1998
    Additional Material: 4 Ill.
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  • 122
    Electronic Resource
    Electronic Resource
    Side chain liquid crystal polyurethanes with azobenzene mesogenic moieties: Influence of spacer length on hydrogen bonding at different temperatures (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2135-2146 
    Details
    ISSN: 0887-624X
    Keywords: SCLC polyurethanes ; azobenzene mesogenic group ; alkyl spacer ; bilayer smectic phases ; hydrogen bonding ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of side chain liquid crystal polyurethanes (CnCNPs), in which the spacer length was varied from 2 to 12 methylene units, were synthesized by the addition polymerization of α-[bis(2-hydroxyethyl)amino]-ω-(4-cyanoazobenzene-4′-oxy)alkanes (CnCN-diols) with hexamethylene diisocyanate. The liquid crystalline properties of CnCNPs were characterized by means of differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. Polyurethanes with spacer length 4 or higher exhibited mesomophic properties. C4CNP and C5CNP exhibited an enantiotropic nematic mesophase, while C6-C12CNPs exhibited enantiotropic bilayer smectic mesophases. CnCNPs have a high tendency to crystallize; crystallization is kinetically controlled. Polyurethane's backbone crystallization is closely related to hydrogen bonding. To establish the role of hydrogen bonding in mesophase formation as well as crystallization, Fourier transform infrared spectroscopy studies of CnCNPs were carried out at different temperatures focusing on H-bonds between the N—H and C=O groups of the urethane backbone. With increasing temperature, C=O and N—H stretching bands were evenly shifted to higher wavenumbers, with two exceptions (C4CNP and C5CNP) discussed in detail in the text. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2135-2146, 1998
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    Initiation mechanisms in free radical polymerization: Competitive reaction of cyanoisopropyl radicals with styrene and acrylonitrile (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2169-2176 
    Details
    ISSN: 0887-624X
    Keywords: free radical ; initiation ; styrene ; acrylonitrile ; copolymerization ; nitroxide trapping ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The competitive reactions of cyanoisopropyl radicals with the mixed monomers styrene and acrylonitrile have been investigated using the nitroxide radical trapping technique. When the trap concentration is kept low, second, third, and even fourth generation (in terms of successive monomer addition) carbon radicals have been observed as trapped products. The ratio of rate constants for the addition of styrene and acrylonitrile to cyanoisopropyl radicals is 2.7 at 75°C and 5.3 at 105°C. These values are compared with the ratios for reactions of these two monomers with a number of other radicals and discussed in terms of the polarities of the radicals and monomers. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2169-2176, 1998
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    Synthesis and properties of new soluble N-phenyl-substituted aromatic-aliphatic and all aromatic polyamides derived from 4,4′-dianilinobiphenyl (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2193-2200 
    Details
    ISSN: 0887-624X
    Keywords: N-phenylated polyamides ; 4,4′-dianilinobiphenyl ; solubility ; thermal behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New N-phenylated aromatic-aliphatic and all aromatic polyamides were prepared by the high-temperature solution polycondensation of 4,4′-dianilinobiphenyl with both aliphatic (methylene chain lengths of 6-11) and aromatic dicarboxylic acid chlorides. All of the aromatic-aliphatic polyamides and the wholly aromatic polyamides exhibited an amorphous nature and good solubility in amide-type and chlorinated hydrocarbon solvents, except for those aromatic polyamides containing p-oriented phenylene or biphenylylene linkages in the backbone; the latter were crystalline and insoluble in organic solvents except m-cresol. The N-phenylated aromatic-aliphatic polyamides and aromatic polyamides had glass transition temperatures in the range of 79-116°C and 207-255°C, respectively, and all the polymers were thermally stable with decomposition temperatures above 400°C in air. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2193-2200, 1998
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    Structure analysis of a soluble polysiloxane-block-polyimide and kinetic analysis of the solution imidization of the relevant polyamic acid (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2237-2245 
    Details
    ISSN: 0887-624X
    Keywords: NMR ; polysiloxane, polysiloxane-block-polyimide ; solution imidization ; kinetic analysis ; structure analysis ; spin-lattice relaxation time ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of polysiloxane-block-polyimides were synthesized by solution imidization of the polyamic acids derived from the combination of 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), and diamino(polysiloxane) (PSX (Mw = 750)) in N-methyl-2-pyrrolidone (NMP). Their structures were analyzed by 1H-, 13C-, and 29Si-NMR spectra as well as by IR spectroscopy. The solid-state NMR spectrum was also measured to determine the spin-lattice relaxation time of the copolyimides. The observed relaxation times of both aromatic and polysiloxane segments were similar in the copolyimides having 10-30 wt % of PSX, while those in the copolyimide with 50 wt % of PSX was significantly different. This may be attributed to the morphology change due to the increase in PSX composition in the polymer backbone. The reduced viscosity of the copolyimides could be controlled by changing the monomer ratio in the feed or by adding an end-capping reagent such as phthalic anhydride into the polymerization system. The kinetic study of the solution imidization revealed that the imidization reaction obeyed second-order kinetics. The activation energy calculated for this imidization was 99.2 kJ/mol, being similar to that for the imidization of the DSDA-based aromatic polyimides. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2237-2245, 1998
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    Synthesis and characterization of new aromatic polyesters and a polyether derived from 2,2-bis(4-hydroxyphenyl)-1,2-diphenylethanone (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2229-2235 
    Details
    ISSN: 0887-624X
    Keywords: polyarylates ; aromatic polyether ; 2,2-bis(4-hydroxyphenyl)-1,2-diphenylethanone ; solubility ; thermal behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New polyarylates having benzopinacolone units were synthesized from 2,2-bis(4-hydroxyphenyl)-1,2-diphenylethanone and aromatic dicarboxylic acid chlorides. The polymers having an inherent viscosity of 0.71-0.94 dL/g were obtained by the two-phase method using toluene as an organic solvent. The polymers were easily soluble in various organic solvents and had high glass transition temperatures in the range of 200-240°C. An aromatic polyether having benzopinacolone unit was also prepared. However, its inherent viscosity was low because of the occurrence of a side reaction. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2229-2235, 1998
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    New polymer syntheses. XC. A-B-A triblock copolymers with hyperbranched polyester A-blocks (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 31-38 
    Details
    ISSN: 0887-624X
    Keywords: triblock copolymers ; polycondensations ; telechelic character ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Telechelic oligo(ether-ketone)s containing two trimethylsiloxy end groups and one methyl group per repeating unit were prepared by polycondensation of 4-fluoro-2′-methyl-4′-(trimethylsiloxy)benzophenone. The telechelic character was achieved by cocondensation of a small amount of silylated bisphenol-P. The end groups of the silylated oligo(ether-ketone)s were acetylated by means of acetyl chloride. On the basis of 1H-NMR end group analyses two samples of α,ω-bis(acetoxy) oligo(ether-ketone)s with DP = 14 and DP ∼ 28 were obtained. These oligo(ether-ketone)s and a 70 or 140 fold molar amount of silylated 3,5-bis(acetoxy)benzoic acid were polycondensed at 270°C in bulk. The resulting A-B-A triblock copolymers were fractionated by dissolution in tetrahydrofuran. In three out of four experiments a small fraction of precipitated material rich in oligo(ether-ketone) was isolated. The purified triblock copolymers were characterized by inherent viscosities and NMR spectra. For those samples containing the long oligo(ether-ketone) block a low degree of crystallinity was observed after annealing. Four additional polycondensations were conducted with an initial reaction temperature of 290°C. In this way a completely soluble and amorphous triblock copolymer was obtained. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 31-38, 1998
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    Liquid crystalline epoxy resins by polyaddition of diglycidyl ether of 4,4′-dihydroxybiphenyl and difunctional aromatic compounds (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 21-29 
    Details
    ISSN: 0887-624X
    Keywords: liquid crystalline polymers ; epoxy resins ; thermotropic ; polymer chain extension ; catalytic polyaddition ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This work is a continuation of the authors' earlier investigations of liquid crystalline epoxy resins prepared from diglycidyl ether of 4,4′-dihydroxybiphenyl (DGE-DHBP), which was used as a mesogenic agent, and aliphatic dicarboxylic compounds, which were used as flexible spacers. In this paper, the synthesis and characterization of liquid crystalline epoxy resins, prepared from DGE-DHBP and difunctional aromatic compounds are described. Three series of liquid crystalline epoxy resins were prepared by chain extension of DGE-DHBP with isomeric hydroxybenzoic and benzenedicarboxylic acids as well as diphenols. An isophthalic-terminated polyether was applied to decrease the temperature of phase transitions. The syntheses were carried out by catalytic polyaddition in the melt. Triphenylphosphine was applied as the catalyst. The resulting epoxy resins were investigated by DSC, polarizing microscope as well as by X-ray and IR spectroscopy. The phase transition temperatures and the type of mesophase of the resulting products depend on the character of the functional groups in the chain extender and on the position of the functional groups in the aromatic ring. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 21-29, 1998
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    Synthesis and properties of new soluble aromatic polybenzoxazoles from 4,4′-diamino-3,3′-dihydroxytriphenylamines and aromatic dicarboxylic acids (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1987-1994 
    Details
    ISSN: 0887-624X
    Keywords: triphenylamine-based bis(o-aminophenol)s ; aromatic polybenzoxazoles ; solubility ; thermal behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new triphenylamine-based bis (o-aminophenol) monomers, 4,4′-diamino-3,3′-dihydroxytriphenylamines, were successfully synthesized by the cesium fluoride-mediated condensation of 2-(benzyloxy)-4-fluoronitrobenzene with aniline derivatives, followed by simultaneous deprotection and reduction. Aromatic polybenzoxazoles having inherent viscosities of 0.58-1.05 dL/g were obtained by the low-temperature solution polycondensation of the bis(aminophenol)s with various aromatic dicarboxylic acid chlorides and the subsequent thermal cyclodehydration of the resultant poly(hydroxyamide)s. All the polybenzoxazoles were amorphous, and most of them were soluble in organic solvents such as m-cresol and o-chlorophenol. Flexible and tough films of polybenzoxazoles could be cast from the DMAc solutions of some aromatic poly(hydroxyamide)s, followed by thermal cyclodehydration. The glass transition temperatures and 10% weight loss temperatures of the polybenzoxazoles under nitrogen were in the range of 262-327 and 610-640°C, respectively. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1987-1994, 1998
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    Asymmetric anionic polymerization of (2-fluorophenyl)(4-fluorophenyl)(2-pyridyl)methyl methacrylate leading to a helical polymer (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2013-2019 
    Details
    ISSN: 0887-624X
    Keywords: asymmetric polymerization ; anionic polymerization ; (2-fluorophenyl)(4-fluorophenyl)(2-pyridyl) methyl methacrylate ; optically active polymer ; helix ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel racemic methacrylate, (2-fluorophenyl)(4-fluorophenyl)(2-pyridyl)-methyl methacrylate1 (2F4F2PyMA), was synthesized and polymerized with chiral complexes of N,N′-diphenylethylenediamine monolithium amide (DPEDA-Li) with (-)-sparteine (Sp), (2S, 3S)-(+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane (DDB), and (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine (PMP) in toluene at -78°C. The monomer showed higher resistance against methanolysis compared with triphenylmethyl methacrylate (TrMA) and several other analogues. In the asymmetric anionic polymerization of 2F4F2PyMA, PMP was found to be a more effective chiral ligand than DDB and Sp and gave quantitatively an optically active polymer with nearly perfect isotacticity. Enantiomer selection was observed in the polymerization of racemic 2F4F2PyMA with the chiral lithium complexes. Chiral recognition ability of the optically active poly(2F4F2PyMA) was examined by an enantioselective adsorption experiment. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2013-2019, 1998
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    Characterization and degradation of the poly(methylphenylsiloxane)-poly(methyl methacrylate) graft copolymer (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2521-2530 
    Details
    ISSN: 0887-624X
    Keywords: poly(methylphenylsiloxane) ; poly(methyl methacrylate) ; graft copolymer ; spin-spin relaxation ; degradation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(methylphenylsiloxane)-poly(methyl methacrylate) graft copolymers (PSXE-g-PMMA) were prepared by condensation reaction of poly(methylphenylsiloxane)-containing epoxy resin (PSXE) with carboxyl-terminated poly(methyl methacrylate) (PMMA), and they were characterized by gel permeation chromatography (GPC), infrared (IR), and 29Si and 13C nuclear magnetic resonance (NMR). The microstructure of the PSXE-g-PMMA graft copolymer was investigated by proton spin-spin relaxation T2 measurements. The thermal stability and apparent activation energy for thermal degradation of these copolymers were studied by thermogravimetry and compared with unmodified PMMA. The incorporation of poly(methylphenylsiloxane) segments in graft copolymers improved thermal stability of PMMA and enhanced the activation energy for thermal degradation of PMMA. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2521-2530, 1998
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    Amine-linked thioxanthones as water-compatible photoinitiators (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2563-2570 
    Details
    ISSN: 0887-624X
    Keywords: thioxanthone derivatives ; water-compatible photoinitiator ; absorption spectrum ; fluorescence ; photopolymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Six amine-linked thioxanthones, i.e., 2-(2-hydroxy-3-[bis(2-hydroxyethyl)amino]propoxy)thioxanthone (HAPTX) and its 4-methyl, 1,3-dimethyl, 1,4-dimethyl, 3,4-dimethyl, and 1,3,4-trimethyl substituted derivatives, were synthesized as water-compatible photoinitiators and identified with FTIR, MS, NMR, and elementary analysis. The absorption and fluorescence properties were studied. Their photoinitiating polymerization efficiencies were tested with a recording dilatometer utilizing acrylamide as monomer in aqueous solution. The results show that the six amine-linked thioxanthones can independently initiate acrylamide polymerization efficiently without additional external amines as co-initiators. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2563-2570, 1998
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    Oxidative polymerization of phenylenediamines catalyzed by horseradish peroxidase (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2593-2600 
    Details
    ISSN: 0887-624X
    Keywords: phenylenediamine ; oxidative polymerization ; enzyme ; horseradish peroxidase ; CD spectrum ; organic solvent ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ortho-, meta-, and para-phenylenediamines were polymerized using hydrogen peroxide as an oxidant and horseradish peroxidase as a catalyst in mixed solvents of 1,4-dioxane and water. The yield of the polymers was strongly dependent on solvent composition, and maximum yields were obtained at 15-30% 1,4-dioxane. The analysis of circular dichroic spectra of the enzyme suggested that enzyme structure was significantly modified at high 1,4-dioxane contents, which may be responsible for the decrease of catalytic activity of the enzyme. On the basis of IR and electronic spectra of the polymers, it was considered that o- and p-phenylenediamine polymers retain disubstituted benzene nuclei, which suggests that the polymerization proceeded mainly via N - N coupling. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2593-2600, 1998
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    Synthesis of alkoxyamine initiators for controlled radical polymerization (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2667-2668 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Syntheses and properties of liquid crystalline N-substituted pyrroles and their polymers (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2691-2698 
    Details
    ISSN: 0887-624X
    Keywords: N-substituted pyrrole ; liquid crystalline polymer ; polypyrrole ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three liquid crystalline N-substituted pyrroles were synthesized from 6-(1-pyrrolyl)hexanol with phenolic derivatives having a mesogenic core of cyclohexylbenzene or biphenyl by Mitsunobu reaction. These pyrroles had two anodic peaks at 1.4 and 1.8 V (vs. SCE). The former was due to an oxidation of the pyrrole moiety and the latter was due to an oxidation of the mesogenic moiety. These pyrrole monomers were polymerized by electrochemical and chemical methods. The potentiostatic method and the chemical method using FeCl3 gave a soluble and fusible polymer, respectively. A polymer having a mesogenic core of cyclohexyl benzene obtained by the chemical method and a polymer having a mesogenic core of biphenylketone obtained by the potentiostatic method had a liquid-crystalline phase. The phase was identified as smectic A by polarizing microscopy and XRD analysis. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2691-2698, 1998
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    Polymerization of acrylamide in the presence of ultrasound and peroxomonosulfate (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2715-2719 
    Details
    ISSN: 0887-624X
    Keywords: polymerization ; acrylamide ; peroxomonosulfate ; ultrasound ; mechanism ; rate parameters ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization of acrylamide (M) in the presence of ultrasound and peroxomonosulfate (PMS) was carried out for the first time for various concentration ranges of monomer and initiator and various temperatures at a constant frequency of 1 Mhz. The rate of polymerization Rp was found to increase with increase in the concentration of monomer and initiator and found to depend on [M] and [PMS]1/2. The rate of disappearance of initiator (-d[PMS]/dt) was also followed simultaneously under the experimental conditions and found to increase linearly with increase in [PMS]. A probable reaction mechanism was proposed on the basis of the observed results, and the individual rate constant were evaluated. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2715-2719, 1998
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    Synthesis and characterization of chiral polyamides derived from glycine and (S)-5-amino-4-methoxypentanoic acid (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2741-2748 
    Details
    ISSN: 0887-624X
    Keywords: stereoregular polymers ; chiral polyamides ; ω-amino acids ; glycine ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereoregular, enantiomerically pure, chiral polyamides of the -AB- type, containing a natural (glycine) and a synthetic [(S)-5-amino-4-methoxypentanoic acid (AMP)] component have been prepared by the active ester polycondensation method. Thus, polyamide 7 was obtained by polycondensation of the conveniently activated H2NGly-AMPCO2R unit (6). In this reaction, 7 appeared accompanied by a considerable amount of cyclic (Gly-AMP)2 (8), which makes the isolation and purification of 7 difficult. The formation of cyclic byproducts could be avoided by preparing and polymerizing the oligoamide H2NGly-AMP-AMPCO2R (11), which has the terminal carboxyl group activated as the pentachlorophenyl ester. The resulting polyamide (12) was obtained in 85% yield and free of macrolactams, such as 8. The new polyamides 7 and 12 were characterized by elemental analysis and infrared and 1H- and 13C-nuclear magnetic resonance spectroscopies. Thermal studies revealed that 12 is crystalline and yields films with spherulitic texture by slow evaporation of formic acid solutions. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2741-2748, 1998
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    Mechanisms of thermal degradation of polystyrene, polymethacrylonitrile, and their copolymers on flash pyrolysis (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2315-2330 
    Details
    ISSN: 0887-624X
    Keywords: thermal degradation mechanism ; poly(styrene-co-methacrylonitrile) ; pyrolysis gas chromatography ; back-biting reaction ; depolymerization ; boundary effect ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanism of thermal degradation of homopolymers of styrene (St) and methacrylonitrile (MAN) and their copolymers was investigated theoretically and experimentally by the pyrolysis gas chromatography using a Curie-point pyrolyzer. Poly(St-co-MAN)s generate dimers and trimers as well as monomers by flash pyrolysis. Parameter α was proposed to account for the competition between the back-biting reaction and depolymerization. The back-biting parameter α is defined as the ratio of rate constants, α = kbb/kdp, where kbb is the rate constant for the back-biting reaction and kdp is that for depolymerization. The back-biting process is followed by β-scission, where dimer and trimer are generated, and directly correlated with the C - H bond dissociation energies in the polymer chain. Using the back-biting parameter α, where 1/α is equal to the zip length n in depolymerization, the boundary effect for the difference of monomer yields from the homopolymers of St and MAN and their copolymers is well explained. The calculated values of boundary effect parameters, βSt and βMAN, agreed well with the experimental results. It was found that thermal degradation mechanisms of homo- and copolymers of vinyl compounds can be analyzed comprehensively using the back-biting parameter α and the boundary effect parameter β. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2315-2330, 1998
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    New polymer syntheses XCIII. Hyperbranched homo- and copolyesters derived from gallic acid and β-(4-hydroxyphenyl)-propionic acid (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2347-2357 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hyperbranched homopolyester of gallic acid (GA) was prepared by polycondensation of acetylated gallic acid in bulk. Copolyesters of gallic acid and 3-hydroxybenzoic acid (3-HBA) or β-(4-hydroxyphenyl)propionic acid (HPPA) were prepared via the silylated monomers. The degree of branching was varied in both series via the molar fraction of gallic acid. A model reaction with silylated 4-methoxybenzoic acid suggests that all three acetoxy groups of gallic acid can react by ester interchange reactions under the chosen reaction conditions. Furthermore, highly branched copolyesters derived from equimolar ratios of HPPA and 2-, 3-, or 4-hydroxybenzoic acid, vanillic acid, or 4-hydroxycinnamic acid were synthesized. All these copolyesters were found to be amorphous with glass transition temperatures (Tg's) far below that of the hyperbranched poly(gallic acid). © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2347-2357, 1998
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    Epoxidation of bacterial polyesters with unsaturated side chains. II. Rate of epoxidation and polymer properties (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2381-2387 
    Details
    ISSN: 0887-624X
    Keywords: bacterial polyesters ; epoxidation of polyesters ; polyhydroxyalkanoates ; crosslinking polyesters ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(3-hydroxyoctanoate-co-3-hydroxy-10-undecenoate)s (PHOUs) with controlled amounts of unsaturated repeating units were epoxidized to various extents with m-chloroperbenzoic acid (MCPBA) in homogeneous solution. The epoxidation reaction was second order, with an initial rate constant of 1.1 × 10-3Lmol-1.s-1 at 20°C, regardless of the unsaturated unit content in PHOU. No substantial change in either molecular weight or molecular weight distribution occurred as a result of epoxidation, but the melt transition temperature and enthalpy of melting both decreased as the unsaturated groups were increasingly converted into epoxide groups. In contrast, the glass transition temperature (Tg) increased by approximately 0.25°C for each 1 mol % of epoxidation, irrespective of the composition of the PHOU. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2381-2387, 1998
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    Sucrose-based epoxy monomers and their reactions with diethylenetriamine (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2397-2413 
    Details
    ISSN: 0887-624X
    Keywords: epoxy allyl sucroses ; epoxy crotyl sucroses ; sucrose-based epoxy monomers ; thermosets ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two sets of sucrose-based epoxy monomers, namely, epoxy allyl sucroses (EAS), and epoxy crotyl sucroses (ECS), were prepared by epoxidation of octa-O-allyl and octa-O-crotyl sucroses (OAS and OCS, respectively). Synthetic and structural characterization studies showed that the new epoxy monomers were mixtures of structural isomers and diastereoisomers that contained varying numbers of epoxy groups per sucrose. EAS and ECS can be tailored to contain an average of one to eight epoxy groups per sucrose. Quantitative 13C-NMR spectrometry and titrimetry were used independently to confirm the average number of epoxy groups per sucrose. Sucrose-based epoxy monomers were cured with diethylenetriamine (DETA) in a differential scanning calorimeter (DSC), and their curing characteristics were compared with those of diglycidyl ether of bisphenol A (DGEBA) and diepoxycrotyl ether of bisphenol A (DECEBA). EAS and DGEBA cured at 100 to 125°C and exhibited a heat of cure of about 108.8 kJ per mol epoxy. ECS and DECEBA cured at 150 and 171°C, respectively, and exhibited a heat of cure of about 83.7 kJ per mol epoxy. Depending upon the degree of epoxidation (average number of epoxy groups per sucrose) and the concentration of DETA, glass transition temperatures (Tgs) of cured EAS varied from -17 to 72°C. DETA-cured ECS containing an average of 7.3 epoxy groups per sucrose (ECS-7.3) showed no DSC glass transition between -140 and 220°C when the ratio of amine (NH) to epoxy group was 1:1 and 1.5:1. Maximum Tgs obtained for DETA-cured DGEBA and DECEBA polymers were 134 and 106°C, respectively. DETA-cured bisphenol A-based epoxy polymers degraded at about 340°C, as observed by thermogravimetric analysis (TGA). DETA-cured sucrose-based epoxy polymers degraded at about 320°C. Sucrose-based epoxies cured with DETA were found to bind aluminum, glass, and steel. Comparative lap shear tests (ASTM D1002-94) showed that DETA-cured epoxy allyl sucroses with an average of 3.2 epoxy groups per sucrose (EAS-3.2) generated a flexible adhesive comparable in bond strength to DGEBA. However, DETA-cured ECS-7.3 outperformed the bonding characteristics of both DGEBA and EAS-3.2. All sucrose-based epoxy polymers were crosslinked and insoluble in water, N,N-dimethylformamide, tetrahydrofuran, acetone, and dichloromethane. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2397-2413, 1998
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    Block copolymers of telechelic poly(phenylene sulfide) and semiaromatic thermotropic liquid crystalline polyester segments (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2707-2713 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report the synthesis and characterization of copolymers comprising poly(phenyl sulfide) (PPS) blocks and semiaromatic thermotropic liquid crystalline polymer (TLCP) blocks. The copolymers, synthesized by melt-transesterification of dicarboxy-terminated poly(phenylene sulfide) with poly(ethylene terephthalate-co-oxybenzoate) (PET/OB), were characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarized light optical microscopy (PLOM). The crystallizability and liquid crystalline properties of the copolymers are greatly influenced by the extent of interchange reactions, the mole percent of oxybenzoate with respect to the PET, the PPS : PET/OB weight ratio, and the reaction time. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2707-2713, 1998
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    Polymerization of diphenylacetylenes having very bulky silyl groups and polymer properties (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2721-2725 
    Details
    ISSN: 0887-624X
    Keywords: poly(diphenylacetylene) ; tantalum catalyst ; metathesis polymerization ; thermal stability ; gas permeability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization and polymer properties of 1-phenyl-2-[4-(triphenylsilyl)phenyl]acetylene (pPh3SiDPA) and 1-phenyl-2-[4-(triisopropylsilyl)phenyl]acetylene (piPr3SiDPA), which have very bulky silyl groups, were examined. These monomers polymerized in good yields in the presence of TaCl5-based catalysts. The highest weight-average molecular weights of poly(pPh3SiDPA) and poly(piPr3SiDPA) reached about 1 × 106 and 4.8 × 106, respectively. The polymers were yellow to orange-colored solids which were soluble in toluene, chloroform, etc., and provided free-standing films by solution casting. The onset temperatures of weight loss of poly(pPh3SiDPA) and poly(piPr3SiDPA) in TGA in air were 430 and 270°C, respectively. The oxygen permeability coefficients of poly(pPh3SiDPA) and poly(piPr3SiDPA) at 25°C were 3.8 and 20 barrers, respectively, and relatively small. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2721-2725, 1998
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    Free radical dispersion polymerization of styrene in a mixture of 2-propanol and tetrahydrofuran (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2757-2761 
    Details
    ISSN: 0887-624X
    Keywords: free radical polymerization ; high-conversion model ; solvent effect ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Free radical dispersion polymerization of styrene in a mixture of 2-propanol and tetrahydrofuran was carried out at 70°C up to high conversions. The influence of the change of the critical chain length on the evolution of the insoluble polymer component was examined. Monomer conversion and the formation of the insoluble polymer component were measured in order to test a mathematical model presented in our previous article. The critical polymer chain length i0, the initiation rate constant kd, and the ratio kp/kt1/2, where kp and kt are propagation and termination rate constants, respectively, have been obtained and compared with those reported in the literature. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2757-2761, 1998
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    Synthesis and electrical-magnetic properties of polyaniline composites (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2799-2805 
    Details
    ISSN: 0887-624X
    Keywords: polyaniline (PANI) ; electrical-magnetic properties ; emeraldine base (EB) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Composites of polyaniline (PANI) with both conducting and ferromagnetic feature were synthesized by an improved method proposed by the authors. The electrical and ferromagnetic properties of the composites were measured as a function of the concentration of KOH solution used during polymerization. The conductivity of the composites at room temperature decreases with the increase of the concentration of KOH; the maximum conductivity of 8.0 × 10-1 S/cm can be obtained when 25 wt % of concentration of KOH was used. For a high concentration of KOH, ferromagnetic properties of the composites including a high saturated magnetization (∼ 10.0 emu/g) depending on the concentration of KOH solution and a lower coercive force (Hc ≈ 0) independent of the concentration of KOH solution were observed. It has been demonstrated that magnetic particles (Fe3O4) with nanometer size in the composites can be attributed to the ferromagnetic properties of the composites observed. For a lower concentration of KOH solution, on the other hand, the magnetic properties of the composites can be decomposed to Curie susceptibility χc depending on the temperature and Pauli susceptibility χP independent of the temperature. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2799-2805, 1998
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    New hydrocarbon side chain liquid crystalline polysiloxane polymers: Synthesis, characterization, and thermotropic behavior (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2849-2863 
    Details
    ISSN: 0887-624X
    Keywords: liquid crystals ; all hydrocarbon ; side chain ; polysiloxane polymers ; smectic B phase ; smectic E phase ; X-ray diffraction ; spin-lattice relaxation time ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of new and high-purity hydrocarbon liquid crystal monomers were synthesized through the acylation reaction, deoxygenation reaction, and Grignard reaction. 1H-NMR spectra and elemental analyses were used to examine their purity. The liquid crystalline polysiloxane polymers were obtained by grafting the monomers onto poly(methylhydrosiloxane). The thermal transition temperature, mesomorphic properties, and mesophase textures of the monomers and the polymers were determined by differential scanning calorimetry (dsc), polarized optical microscopy, and X-ray diffraction analysis. Moreover, we observed the even-odd effect of the smectic/isotropic transition temperature with the length variation of the substituents. In this study, we found by X-ray diffraction that the liquid crystalline polysiloxane polymers undergo a transition from smectic B to smectic E mesophase. However, dsc has difficulty detecting the phase transition process. By considering the spin-lattice relaxation time (T1), we can systematically explain the relation between the flexibility of the substituent with the smectic/isotropic transition temperature. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2849-2863, 1998
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    Determination of chain transfer constant to dodecanethiol in styrene/methyl methacrylate and butyl acrylate/methyl methacrylate copolymerization and effect of chain length on composition and stereochemical configuration of copolymers (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2913-2925 
    Details
    ISSN: 0887-624X
    Keywords: dodecanethiol ; styrene-methyl methacrylate ; butyl acrylate-methyl methacrylate ; chain transfer constants ; stereochemical configuration ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Free radical copolymerization of styrene/methyl methacrylate (S/MMA) and butyl acrylate/methyl methacrylate (BA/MMA) in the presence of n-dodecanthiol (DDT) has been studied at 60°C in a 3 mol/L benzene solution using 2,2′-azobis(isobutyronitrile) (AIBN) as initiator. Overall chain transfer constant to DDT has been determined for both copolymerization systems, as a function of monomer feed composition using complete molecular weight distribution and the Mayo method. Overall transfer coefficients have values which are dependent on both monomer feed composition and individual comonomer transfer values. Composition, sequence distribution, and stereoregularity of copolymers obtained are, in our experimental conditions, independent of copolymer molecular weight. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2913-2925, 1998
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    Spontaneous alternating copolymerization of N-phenylmaleimide with ethyl α-phenylacrylate (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2927-2931 
    Details
    ISSN: 0887-624X
    Keywords: N-phenylmaleimide ; ethyl α-phenylacrylate ; alternating copolymer ; contact-charge transfer complex ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spontaneous copolymerization of N-phenylmaleimide (NPMI) (M1) with ethyl α-phenylacrylate (EPA)(M2) were carried out in dioxane at 85°C. A high alternating tendency was observed. The monomer reactivity ratios were r1 = 0.07 ±0.01 and r2 = 0.09 ± 0.02. The maximum copolymerization rate and molecular weight occurs at 70-80 mol% (M1) in feed ratio. The spontaneous alternating copolymerization is considered to be carried out via a contact-type charge transfer complex (CTC) formed between the monomers. Thermogravimetric analyses (TGA) indicate the resulting copolymers have high thermal stability. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2927-2931, 1998
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    Synthesis and characterization of biodegradable poly(L-aspartic acid-co-PEG) (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2949-2959 
    Details
    ISSN: 0887-624X
    Keywords: aspartic acid anhydride ; poly(ethylene glycol) ; poly(L-aspartic acid-co-PEG) ; biodegradable polymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The melt polycondensation reaction of the prepolymer prepared from N-(benzyloxycarbonyl)-L-aspartic acid anhydride (N-CBz-L-aspartic acid anhydride) and low molecular weight poly(ethylene glycol) (PEG) using titanium isopropoxide (TIP) as a catalyst produced the new biodegradable poly(L-aspartic acid-co-PEG). This new copolymer had pendant amine functional groups along the polymer backbone chain. The optimal reaction conditions for the preparation of the prepolymer were obtained by using a 0.12 mol % of p-toluenesulfonic acid with PEG 200 for 48 h. The weight-average molecular weight of the prepolymer increased from 1,290 to 31,700 upon melt polycondensation for 6 h at 130°C under vacuum using 0.5 wt % TIP as a catalyst. The synthesized monomer, prepolymer, and copolymer were characterized by FTIR, 1H- and 13C-NMR, and UV spectrophotometers. Thermal properties of the prepolymer and the protected copolymer were measured by DSC. The glass transition temperature (Tg) of the prepolymer shifted to a significantly higher temperature with increasing molecular weight via melt polycondensation reaction, and no melting temperature was observed. The in vitro hydrolytic degradation of these poly(L-aspartic acid-co-PEG) was measured in terms of molecular weight loss at different times and pHs at 37°C. This pH-dependent molecular weight loss was due to a simple hydrolysis of the backbone ester linkages and was characterized by more rapid rates of hydrolysis at an alkaline pH. These new biodegradable poly(L-aspartic acid-co-PEG)s may have potential applications in the biomedical field. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2949-2959, 1998
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    Highly branched radial block copolymers via dendritic initiation of aliphatic polyesters (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2793-2798 
    Details
    ISSN: 0887-624X
    Keywords: highly branched radial block copolymers ; dendritic initiation ; alipatic polyesters ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Living ring opening polymerization of ε-caprolactone initiated from the numerous chain-end hydroxymethyl groups of the analogous dendrimeric and hyperbranched polyesters derived from 2,2-bis(hydroxymethyl) propionic acid is described. By controlling the size of the dendritic macromolecule and the molar ratio of ε-caprolactone, a variety of highly branched radial block copolymers are obtained. Comparison of the results obtained for the dendrimeric and hyperbranched initiators demonstrates that the reactivity of the chain-end hydroxymethyl groups in the dendrimer are significantly greater than in the isomeric hyperbranched case. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2793-2798, 1998
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    Stimuli-responsive polymers. III. Poly(aryl ether ketone amide)s with reversible trans- ↔ cis-4,4′-azobenzene and fixed 2,2′-binaphthyl kinking elements in the main chainDuPont contribution no. 7761. (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2827-2837 
    Details
    ISSN: 0887-624X
    Keywords: stimuli-responsive polymers ; trans-cis isomerization ; NMR spectroscopy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The low-temperature polycondensation of trans-azobenzene-4,4′-dicarbonyl chloride with (S)-(-)-1,1′-binaphthyl-2,2′-diamine and/or 1,4-bis(3-aminophenoxy-4′-benzoyl)benzene afforded a new series of poly(aryl ether ketone amide)s with both fixed and photoinducible kinking elements positioned randomly along the main chain. In their lower energy, trans-azobenzene configurations, the orange, film-forming materials were amorphous, highly tractable, and thermally stable under air or nitrogen up to about 420°C. Variants endowed with higher loadings of the bent binaphthyl monomer were soluble in a variety of organic solvent media including THF and acetone. The introduction of cis-azobenzene backbone kinks into these materials was carried out by irradiating the polymer solutions with near-UV light. Up to 70% of the azobenzene moieties in these polymers were capable of assuming the higher energy cis-configuration, thus greatly increasing the number of bent or kinked sites positioned along each polymer backbone. In solution, reverse cis → trans isomerization reactions were triggered thermally and were quantitatively tracked by both optical absorbance and 1H NMR spectroscopies. Activation parameters calculated for cis → trans reorganization of the polymer backbone were not dependent upon the chemical composition or molecular weight of the polymers but did exhibit a small dependence upon the nature of the solvent medium used to conduct the isomerization experiment. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2827-2837, 1998
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    Living radical polymerization of methylstyrenes by a stable nitroxyl radical, and stability of the aminoxy chain end (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 269-276 
    Details
    ISSN: 0887-624X
    Keywords: living radical polymerization ; methylstyrene ; MTEMPO ; stability ; aminoxy chain end ; steric hindrance ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical polymerization of 2-, 3-, and 4-methylstyrenes (MeSts) was investigated with benzoyl peroxide (BPO) as an initiator, in the presence of 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (MTEMPO). The polymerization was performed in bulk for 3.5 h at 95°C, and then continued for a defined time at 125°C, to give the corresponding poly(MeSt)s with narrow polydispersity in high yield. It was found that the polymerization proceeded in accordance with a living mechanism, because the molecular weight of the resulting polymers was proportional to the conversion, and to the reciprocal of the initial concentration of MTEMPO. It was found that steric hindrance between the methyl group of 2-MeSt, and the tetramethyl ones of MTEMPO, significantly contributed to the rate of polymerization, and to the stability of the growing polymer chain end. The stability decreased in the order of 2- 〉 3- 〉 4-MeSt, by occurrence of decomposition, which was caused by disproportionation of the growing chain end. However, the steric hindrance had no effect on the tacticity of the resulting polymer. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36, 269-276, 1998
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    Synthesis and characterization of poly(benzazoles) containing the bicyclo[2.2.2]octane moiety (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 277-281 
    Details
    ISSN: 0887-624X
    Keywords: poly(benzazoles) ; bicyclo[2.2.2]octane ; aromatization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(benzobisoxazoles) (PBOs), poly(benzobisthiazoles) (PBTs) and copolymers thereof containing the 2,5-dihydroxybicyclo[2.2.2]octane moiety have been prepared and studied. The homopolymers were synthesized by the polycondensation of 2,5-dihydroxybicyclo[2.2.2]octane-1,4-dicarboxylic acid with 4,6-diamino-1,3-benzenediol dihydrochloride or 2,5-diamino-1,4-benzenedithiol dihydrochloride in poly(phosphoric acid). Random and block copolymers (PBO-PBT) were also prepared. The polymers were characterized by solubility, X-ray diffraction, spectroscopy (infrared and solid-state 13C nuclear magnetic resonance), and thermal analysis such as differential scanning calorimetry and thermogravimetric analysis. Thermogravimetric analysis showed thermal stability of the polymers above 375°C in air and under argon atmosphere. The polymers exhibited high resistance to organic and inorganic solvents. The polymers were converted to the more stable aromatic polymers via dehydration and retro Diels-Alder reactions of the 2,5-dihydroxybicyclo[2.2.2]octyl moiety by pyrolysis. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 277-281, 1998
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    Synthesis and thermal analysis of branched and “kinked” poly(ethylene terephthalate) (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 309-317 
    Details
    ISSN: 0887-624X
    Keywords: thermal analysis ; branched poly(ethylene terephthalate) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(ethylene terephthalate) (PET) was synthesized by self-condensation of bis-(2-hydroxyethyl) terephthalate (BHET). Copolymerization of BHET with ethyl, bis-3,5-(2-hydroxyethoxy) benzoate (EBHEB) and ethyl, 3-(2-hydroxyethoxy) benzoate (E3HEB) yielded copolymers that contain varying amounts of branching and kinks, respectively. Copolymers of BHET with ethyl, 4-(2-hydroxyethoxy) benzoate (E4HEB), in which only the backbone symmetry is broken but without disruption of the linearity, were also prepared for comparison. The composition of the copolymers were established from their 1H-NMR spectra. The intrinsic viscosity of all the copolymers indicated that they were of reasonably high molecular weights. The thermal analysis of the copolymers using DSC showed that both the melting temperatures (Tm) and the percent crystallinity (as seen from the enthalpies of melting) (ΔHm) decreased with increasing comonomer (defect concentration) content, although their glass transition temperatures (Tg) were less affected. This effect was found to be most pronounced in the case of branching, while the effects of kinks and linear disruptions, on both Tm and ΔHm, were found to be similar. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 309-317, 1998
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    Profile of oxidation in irradiated polyethylene (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 329-339 
    Details
    ISSN: 0887-624X
    Keywords: ultrahigh molecular weight polyethylene (UHMWPE) ; radiation sterilization ; orthopedic prosthesis ; subsurface oxidation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Following gamma irradiation in air which causes bond scission and yields large concentrations of peroxy radicals, maximum oxidation and an increase in crystallinity occurs on the surface of ultrahigh molecular weight polyethylene. Here, bimolecular reactions of peroxy radicals generate carbonyls, mostly ketones. On the polymer surface, peroxy radicals continue to react over time periods of years to generate carbonyls and chain scission. Peroxy radicals in the interior of the polymer abstract hydrogens and form hydroperoxides, inducing chain reactions and a slow but continue increase of ketone. Within the polymer sample, to a decreasing depth with increasing dose, a reduced concentration of oxygen is available to react with radiolytic radicals, so that more efficient crosslinking and a low level of hydroperoxide chain reaction occur. After long periods of time a surface maximum in carbonyl concentration is produced. Heating polyethylene in high pressures of oxygen accelerates the oxidative process. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 329-339, 1998
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    Living cationic polymerization of vinyl ethers with carboxylic acid/tin tetrahalide initiating systems. I. New initiating systems based on acetic acid and selection of Lewis acid and basic additive leading to living polymers with low polydispersity (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 3173-3185 
    Details
    ISSN: 0887-624X
    Keywords: cationic polymerization ; living polymerization ; vinyl ether ; initiator ; acetic acid ; tin tetrabromide ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic polymerization of isobutyl vinyl ether (IBVE) with acetic acid (CH3COOH)/tin tetrahalide (SnX4: X = Cl, Br, I) initiating systems in toluene solvent at 0°C was investigated, and the reaction conditions for living polymerization of IBVE with the new initiating systems were established. Among these tin tetrahalides, SnBr4 was found to be the most suitable Lewis acid to obtain living poly(IBVE) with a narrow molecular weight distribution (MWD). The polymerization with the CH3COOH/SnBr4 system, however, was accompanied with the formation of a small amount of another polymer fraction of very broad MWD, probably due to the occurrence of an uncontrolled initiation by SnBr4 coupled with protonic impurity. Addition of 1,4-dioxane (1-1.25 vol %) or 2,6-di-tert-butylpyridine (0.1-0.6mM) to the polymerization mixture completely eliminated the uncontrolled polymer to give only the living polymer with very narrow MWD (Mw/Mn ≤ 1.1; Mw, weight-average molecular weight; Mn, number-average molecular weight). The Mn of the polymers increased in direct proportion to monomer conversion, continued to increase upon sequential addition of a fresh monomer feed, and was in good agreement with the calculated values assuming that one CH3COOH molecule formed one polymer chain. Along with these results, kinetic study and direct 1H-NMR observation of the living polymerization indicated that CH3COOH and SnBr4 act as so-called “initiator” and “activator”, respectively, and the living polymerization proceeds via an activation of the acetate dormant species. The basic additives such as 1,4-dioxane and 2,6-di-tert-butylpyridine would serve mainly as a “suppressor” of the uncontrolled initiation by SnBr4. The polymers produced after quenching the living polymerization with methanol possessed the acetate dormant terminal and they induced living polymerization of IBVE in conjunction with SnBr4 in the presence of 1,4-dioxane. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3173-3185, 1998
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    Syntheses of poly(siloxane)-supported zirconocene catalysts and application to olefin polymerizations (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 421-428 
    Details
    ISSN: 0887-624X
    Keywords: poly(siloxane)-supported zirconocene catalysts ; polymerizations of ethene and propene ; copolymerization of ethene with 1-octene ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(siloxane)s with bisindenyl, bisfluorenyl, bis(1,2,3,4-tetramethylcyclopentadienyl), bis(2,4,7-trimethylindenyl) and monoindenylmethyl side groups were synthesized by condensation of the corresponding dichlorosilanes and water. For reference, diphenylsilanediol or hydroquinone was also employed in place of water. A series of poly(siloxane)-supported zirconocene catalysts were then prepared from these precursors and applied to ethene and propene polymerizations as well as to the copolymerization of ethene with 1-octene in the presence of methylalumoxane. The polymerization activity of the new supported metallocenes depends drastically upon the substituents in the siloxane backbone. The zirconocene catalysts supported on poly(bisindenylsiloxane) and poly(bisfluorenylsiloxane) give the highest activities for ethene and propene polymerizations, respectively. The weight-average molecular weights of the polymers are also markedly dependent upon the substituents. On the other hand, the molecular mass distributions (MMD) are generally not so sharp, suggesting that the active species formed in these supported catalysts are not uniform. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 421-428, 1998
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    Cyclic(arylene ether) oligomers containing the phenylphosphine oxide moiety (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 519-526 
    Details
    ISSN: 0887-624X
    Keywords: cyclic oligomer ; ring-opening polymerization ; phenylphosphine oxide ; phosphorous ; MALDI-TOF-MS ; poly(arylene ether) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of cyclic(arylene ether) oligomers containing the phenylphosphine oxide moiety has been synthesized by reaction of bis(4-fluorophenyl)phenylphosphineoxide with dihydroxy compounds 1a-d as well as 1,2-dihydro-4-(4-hydroxyphenyl) (2H)phthalazin-1-one in DMF in the presence of anhydrous K2CO3 under high dilution conditions. These cyclic oligomers are amorphous and have high solubility in organic solvents. The MALDI-TOF-MS technique has been used as a powerful tool to analyze these cyclic systems. The cyclic(arylene ether) oligomers readily undergo anionic ring-opening polymerization in the melt at 350°C by using potassium 4,4′-biphenoxide as the initiator, affording linear, high molecular weight poly(arylene ether)s containing the phenylphosphine oxide moiety. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 519-526, 1998
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  • 159
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    Mechanism of the immobilization of surfactants on polymeric surfaces by means of an argon plasma treatment: Influence of the chemical structure of surfactant and substrate (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1829-1846 
    Details
    ISSN: 0887-624X
    Keywords: surface modification ; argon plasma treatment ; poly(ethylene) ; poly(propylene) ; poly(cis-butadiene) ; carboxylic acid groups ; XPS ; SSIMS ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this article, a study on the mechanism of the immobilization of surfactants on polymeric surfaces by means of an argon plasma treatment is described. The unsaturated surfactant sodium 10-undecenoate [C11(:)] and the saturated surfactant sodium dodecanoate (C12) were immobilized on poly(ethylene) (PE), poly(propylene) (PP), and poly(cis-butadiene) (PB) surfaces. This was accomplished by treating polymeric substrates that were coated with C11(:) or C12 with an argon plasma. Derivatization X-ray Photoelectron Spectroscopy (XPS) and Static Secondary Ion Mass Spectrometry (SSIMS) showed that during the plasma treatment surfactants were covalently coupled to the polymeric surfaces. The chemical structure of both the surfactant and the polymeric substrate influenced the immobilization efficiency. At an optimal treatment time of 5 s, about 28 and 6% of the initial amount of carboxylate groups in the precoated C11(:) and C12 layer, respectively, was retained at the PE surface. The immobilization efficiencies of C11(:) and C12 on PP were about 20 and 9%, respectively. The immobilization efficiency of C11(:) and C12 on PB were both about 7%. The results obtained in this study indicate that the immobilization proceeds via a radical mechanism. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1829-1846, 1998
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    Chemical reactions occurring in the thermal treatment of PC/PMMA blends (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1873-1884 
    Details
    ISSN: 0887-624X
    Keywords: polycarbonate ; poly(methyl methacrylate) ; blends ; exchange reactions ; mass spectrometry ; thermal degradation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemical reactions occurring in the thermal treatment of bisphenol-A polycarbonate (PC) and poly(methyl methacrylate) (PMMA) blends have been investigated by nuclear magnetic resonance (NMR), mass spectrometry (MS), size exclusion chromatography (SEC), and thermogravimetry (TG). Our results suggest that in the melt-mixing of PC/PMMA blends, at 230°C, no exchange reactions occur and that only the depolymerization reaction of PMMA has been observed. In the presence of an ester-exchange catalyst (SnOBu2), an exchange reaction was found to occur at 230°C, but no trace of PC/PMMA graft copolymer has been observed. Instead, an exchange reaction between the monomer methyl methacrylate (MMA), generated in the unzipping of PMMA chains, and the carbonate groups of PC has been suggested. This is due to the diffusion of MMA at the interface or even into the PC domains, where it can react with PC producing low molar mass PC oligomers bearing methacrylate and methyl carbonate chain ends and leaving the undecomposed PMMA chains unaffected. The TG curves of PC/PMMA blends prepared by mechanical mixing and by casting from THF show two separated degradation steps corresponding to that of homopolymers. This behavior is different from that of a transparent film of PC/PMMA blend, obtained by solvent casting from DCB/CHCl3, which shows a single degradation step indicating that the degradation rate of PC is increased by the presence of PMMA in the blend. The thermal degradation products obtained by DPMS of this blend consist of methyl methacrylate (MMA), cyclic carbonates arising from the degradation of PMMA and PC, respectively, and a series of open chain bisphenol-A carbonate oligomers with methacrylate and methyl carbonate terminal groups. The presence of the latter compounds suggests a thermally activated exchange reaction occurring above 300°C between MMA and PC. The presence of bisphenol-A carbonate oligomers bearing methyl ether end groups, generated by a thermally activated decarboxylation of the methyl carbonate end groups of PC, has also been observed among the pyrolysis products. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1873-1884, 1998
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    Phthalonitrile cure reaction with aromatic diamines (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1885-1890 
    Details
    ISSN: 0887-624X
    Keywords: phthalonitrile monomer ; thermoset ; curing agent ; processability ; thermal stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phthalonitrile monomers can be polymerized thermally in the presence of small amounts of curing agents into thermosetting polymers. The thermosets exhibit outstanding thermo-oxidative stability, display good mechanical properties, and offer promise as matrices for composite applications. The phthalonitrile cure reaction is typically accomplished with an aromatic diamine, 1,3-bis(3-aminophenoxy)benzene (m-APB), added in the range of 1.5-2% by weight of the monomer in the melt phase. This article addresses the cure reaction with a sulfone-containing diamine, bis[4-(4-aminophenoxy)phenyl] sulfone (p-BAPS), which shows lower volatility as determined from thermogravimetric studies (TGA) compared to m-APB at the processing temperatures typically employed for phthalonitrile cures. Rheometric studies conducted to monitor the viscosity increase during a cure reaction suggest that the cure reaction with m-APB is faster compared to the reaction with p-BAPS. Even though differences are seen in the initial cure rates, the final cured products are similar in terms of the glass transition temperatures and thermal and oxidative stabilities. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1885-1890, 1998
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    Synthesis and properties of soluble aromatic polyimides from 2,2′-bis(3,4-dicarboxyphenoxy)-1,1′-binaphthyl dianhydride and aromatic diamines (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1937-1943 
    Details
    ISSN: 0887-624X
    Keywords: 2,2′-bis(3,4-dicarboxyphenoxy)-1,1′-binaphthyl dianhydride ; aromatic polyimides ; solubility ; thermal behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatic tetracarboxylic dianhydride having crank and twisted noncoplanar structure, 2,2′-bis(3,4-dicarboxyphenoxy)-1,1′-binaphthyl dianhydride, was synthesized by the reaction of 4-nitrophthalonitrile with 2,2′-dihydroxy-1,1′-binaphthyl, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). Binaphthyl-2,2′-diyl-containing novel aromatic polyimides having inherent viscosities up to 0.67 dL/g were obtained by the one-step polymerization process starting from the bis(ether anhydride) and various aromatic diamines. All the polyimides showed typical amorphous diffraction patterns. Most of the polyimides were readily soluble in common organic solvents such as N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and pyridine. These aromatic polyimides had glass transition temperatures in the range of 280-350°C, depending on the nature of the diamine moiety. All polymers were stable up to 400°C, with 10% weight loss being recorded above 485°C in air. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1937-1943, 1998
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    Preparation of an α-cyclodextrin-linked chitosan derivative via reductive amination strategy (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1965-1968 
    Details
    ISSN: 0887-624X
    Keywords: chitosan ; α-cyclodextrin ; reductive amination ; host-guest complex ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
    Additional Material: 3 Ill.
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    Photopolymerization of methyl methacrylate using a morpholine-sulfur dioxide charge-transfer complex as the photoinitiator (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1973-1979 
    Details
    ISSN: 0887-624X
    Keywords: photopolymerization ; morpholine-sulfur dioxide complex ; kinetic nonideality ; methyl methacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photopolymerization of the vinyl monomer (M) of methyl methacrylate (MMA) was kinetically studied by using near-UV/visible light at 40°C and employing a morpholine (MOR)-sulfur dioxide (SO2) charge-transfer (C-T) complex as the photoinitiator. The rate of polymerization (RP) was found to be dependent on the morpholine: sulfur dioxide mole ratio; the 1 : 2 (MOR-SO2) complex acted as the latent initiator complex C which underwent further complexation with the monomer molecules to give the actual initiating complex I. Using the 1 : 2 (MOR-SO2) C-T complex as the latent initiator, the observed kinetics may be expressed as RP [MOR-SO2]0.27[M]1.10. Benzoquinone behaved as a strong inhibitor. Polymers obtained tested positive for the incorporation of a sulphonate-type end group. Polymerization followed a radical mechanism. Kinetic nonideality as revealed by a low initiator exponent and monomer exponent of greater than unity was explained on the basis of a prominent primary radical termination effect. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1973-1979, 1998
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    A versatile and efficient synthesis of alkoxyamine LFR initiators via manganese based asymmetric epoxidation catalysts (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2161-2167 
    Details
    ISSN: 0887-624X
    Keywords: alkoxyamine ; living free radical polymerizations ; asymmetric epoxidation ; Jacobsen's catalyst ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
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    Synthesis and characterization of new polyamides derived from 1,6-bis[4-(4-aminophenoxy)phenyl]diamantane (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2185-2192 
    Details
    ISSN: 0887-624X
    Keywords: high-temperature polyamide ; diamantane ; characterization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of new polyamides 3 were synthesized by direct polycondensation of the 1,6-bis[4-(4-aminophenoxy)phenyl]diamantane (1) with various dicarboxylic acids. The polyamides had inherent viscosities of 0.45-1.90 dL/g and number-average molecular weights (Mn) of 24,000-110,000. Dynamic mechanical analysis (DMA) reveals that polymers 3 have two relaxations on the temperature scale between -100 and 400°C. Their α relaxations occurred at high temperatures, ranging from 338 to 389°C. Moreover, these polymers remained quite stable at high temperatures and maintained good mechanical properties (G′ = ca. 108 Pa) up to temperatures close to the main transition markedly exceeding 350°C. Due to the bulky diamantane elements and the flexible ether segments, the polymers 3 were amorphous and soluble in a number of organic solvents such as pyridine, N-methyl-2-pyrrolidone (NMP), and N,N-dimethylacetamide (DMAc). The polyamides 3 have tensile strengths of 56.7-90.2 MPa, elongation to breakage values of 7.5-27.7%, and initial moduli of 1.8-2.1 GPa. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2185-2192, 1998
    Additional Material: 4 Ill.
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    Novel mechanism for the formation of long-chain branching in polyethylene (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2889-2898 
    Details
    ISSN: 0887-624X
    Keywords: long-chain branching ; polymerization ; catalysts ; polyethylene ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyethylene produced by a vanadium-based polymerization catalyst contains long-chain branching as determined by NMR and rheology, even though the polymer has very low levels of vinyl unsaturation. A new mechanism is proposed for the formation of the long-chain branching, which involves C—H bond activation of the polyethylene backbone through a σ-bond metathesis reaction, followed by ethylene insertion at the new V—C bond. Consistent with the proposed C—H bond activation mechanism, the polymerization catalyst was also found to insert ethylene into the C—H bonds of alkanes such as heptane. A bridged metallocene catalyst was also found to activate C—H bonds of alkanes suggesting this new mechanism may explain the formation of long-chain branching in some metallocene-produced polyethylene. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2889-2898, 1998
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    Kinetic and ESR studies on radical polymerization of methyl methacrylate in the presence of fullerene (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2905-2912 
    Details
    ISSN: 0887-624X
    Keywords: radical polymerization ; fullerene 60 ; methyl methacrylate ; fullerene radical ; ESR spectrum ; starlike copolymer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of fullerene (C60) on the radical polymerization of methyl methacrylate (MMA) in benzene was studied kinetically and by means of ESR, where dimethyl 2,2′-azobis(isobutyrate) (MAIB) was used as initiator. The polymerization rate (Rp) and the molecular weight of resulting poly(MMA) decreased with increasing C60 concentration ((0-2.11) × 10-4 mol/L). The molecular weight of polymer tended to increase with time at higher C60 concentrations. Rp at 50°C in the presence of C60 (7.0 × 10-5 mol/L) was expressed by Rp = k[MAIB]0.5[MMA]1.25. The overall activation energy of polymerization at 7.0 × 10-5 mol/L of C60 concentration was calculated to be 23.2 kcal/mol. Persistent fullerene radicals were observed by ESR in the polymerization system. The concentration of fullerene radicals was found to increase linearly with time and then be saturated. The rate of fullerene radical formation increased with MAIB concentration. Thermal polymerization of styrene (St) in the presence of resulting poly(MMA) seemed to yield a starlike copolymer carrying poly(MMA) and poly(St) arms. The results (r1 = 0.53, r2 = 0.56) of copolymerization of MMA and St with MAIB at 60°C in the presence of C60 (7.15 × 10-5 mol/L) were similar to those (r1 = 0.46, r2 = 0.52) in the absence of C60. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2905-2912, 1998
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    Synthesis and chain structure of ethylene terephthalate-ε-caprolactone copolyesters (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2961-2969 
    Details
    ISSN: 0887-624X
    Keywords: segmented TCL copolyesters ; hard segment content ; chemical structure ; sequence structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of ethylene terephthalate-ε-caprolactone copolyesters (TCL) with different hard segment contents were synthesized and characterized by GPC, NMR, and DSC. The analysis from high-field 1H-NMR reveals that the transesterification between ET and CL segments during synthesis is unavoidable, so TCL copolyesters are segmented copolyesters with certain random properties, as shown by the specific chemical and sequence structure of TCL copolyester chains and as confirmed by their crystallization behavior. The stress-strain test shows that TCL copolyesters with different hard segment contents may possess rubberlike or toughening plastic mechanical properties. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2961-2969, 1998
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    Polyketomalonates by catalytic oxidation of glycerol. I (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2993-2994 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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    Novel thermoplastic elastomers. I. Synthesis and characterization of star-block copolymers of PSt-b-PIB arms emanating from cyclosiloxane coresPart XVIII of the series New Polyisobutylene Stars. For part XVII, see: J. S. Shim, S. Asthana, N. Omura, and J. P. Kennedy, Polym. Prepr., 39 (1), 196 (1998). (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2997-3012 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterization of novel thermoplastic elastomers consisting of multiple polystyrene-b-polyisobutylene (PSt-b-PIB) arms emanating from cyclosiloxane cores is described. The synthesis involved the sequential living cationic block copolymerization of styrene (St) and isobutylene (IB), followed by quantitative allylic end-functionalization of the living PSt-b-PIB+ to produce PSt-b-PIB—CH2— CH=CH2 prearms, and finally linking by hydrosilation of these prearms with Si—H-containing cyclosiloxanes (e.g., 2,4,6,8,10,12-hexamethylcyclohexasiloxane, DH6). Two types of star-blocks, namely primary and higher-order star-blocks, were prepared: Primary star-blocks containing 3-9 PSt-b-PIB arms were obtained by using various cyclosiloxanes (DH6 to DH12) and a close to exact stoichiometry between the Si—H and allyl groups, [Si—H]/[C=C] ∼ 1, in the essential absence of moisture ([H2O] ∼ 100 ppm). Higher-order star-blocks consisting of 13-24 PSt-b-PIB arms radiating from complex coupled cyclosiloxanes were prepared by the use of Si—H/allyl ratios significantly larger than unity ([Si—H]/[C=C] = 2-3) in the presence of controlled amounts of moisture ([H2O] ∼ 600 ppm). Reaction conditions (temperature, concentration, stoichiometry, solvent nature, catalyst concentration, etc.) for efficient syntheses have been developed. The products were characterized by 200 and 600 MHz 1H-NMR spectroscopy and triple-detector (RI, UV, LLS) GPC. The microstructure of the condensed cores in the higher-order star-blocks was studied by 2D-NMR (HMQC) spectroscopy, and the number of cyclosiloxane rings in the cores (i.e., the content (wt %) of cores in the star-blocks) was determined. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2997-3012, 1998
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    Synthesis and properties of phosphorus-containing polyesters derived from 2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)-1,4- hydroxyethoxy phenylene (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 3051-3061 
    Details
    ISSN: 0887-624X
    Keywords: flame retardancy ; polyester ; activation energy of degradation ; LOI ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of phosphorous-containing aliphatic polyesters were synthesized by high-temperature solution condensation of 2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)-1,4-hydroxyethoxy phenylene (III) with various aromatic acid chlorides in o-dichlorobenzene. All polyesters are amorphous and readily soluble in many organic solvents such as DMAc, NMP, DMSO, and o-dichlorobenzene at room temperature or upon heating. These polyesters are thermally quite stable. The glass transition temperatures of these aliphatic polyesters ranged from 126.6 to 162.2°C. The degradation temperatures (Td onset) in nitrogen ranged from 424 to 448°C, and the char yields at 700°C are 20-32%. The activation energies of degradation ranged from 160.9 to 226.0 kJ/mol. The LOIs of these polyesters ranged from 36 to 43. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3051-3061, 1998
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    Radiation effects on the thermal degradation of poly(vinyl chloride) and poly(vinyl alcohol) (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 3089-3095 
    Details
    ISSN: 0887-624X
    Keywords: radiation ; thermal degradation ; poly(vinyl chloride) ; poly(vinyl alcohol) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radiation effects on the formation of conjugated double bonds in the thermal degradation of poly(vinyl chloride) (PVC) and poly(vinyl alcohol) (PVA) were investigated. Thin films of PVC and PVA were either irradiated with γ-rays at ambient temperature (pre-irradiation) and then subjected to thermal treatment, or irradiated at elevated temperatures (in situ irradiation). An extensive enhancement of the thermal degradation was observed for the pre-irradiation of the PVC films, which was more effective than the effect of the in situ irradiation at the same absorption dose. For the PVA degradation, however, the effect of the in situ irradiation was larger than that of the pre-irradiation. The results were explained and related mechanisms were discussed based on radiation-induced chemical reactions and their individual contributions to the thermal degradation behaviors of the two polymers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3089-3095, 1998
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    Pulsed-plasma polymerization of 1-vinyl-2-pyrrolidone: Synthesis of a linear polymer (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 3121-3129 
    Details
    ISSN: 0887-624X
    Keywords: pulsed-plasma ; 1-vinyl-2-pyrrolidone ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The RF plasma induced polymerization of 1-vinyl-2-pyrrolidone was examined under variable duty-cycle pulsed-plasma conditions. Large-scale progressive changes in the composition of the resultant polymeric films were observed with sequential changes in the plasma duty cycle employed during polymerization, all other plasma variables held constant. The film compositional changes obtained are in the direction of increased retention of the lactam ring of the monomer in the resultant polymers as the duty cycles employed (i.e., the ratio of plasma on to plasma off times) were decreased. Particularly significant are the relatively linear polymeric structures obtained under the exceptionally low-average power deposition conditions made accessible with the pulsed plasma technique. XPS and FTIR spectroscopic examination of these latter films reveal compositions that are similar to those obtained by conventional (i.e., nonplasma) synthesis of the linear polymer. The film chemistry controllability demonstrated in the present study is achieved while maintaining the many advantages of the plasma polymerization approach for surface modifications. This work provides additional support for use of the pulsed operational mode as an effective means of film chemistry control, in particular extending the plasma polymerization technique to include synthesis of linear polymers, in lieu of the more highly crosslinked structures typically produced in conventional continuous-wave plasma polymerization processes. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3121-3129, 1998
    Additional Material: 7 Ill.
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    Synthesis, geometric structure, and properties of poly(phenylacetylenes) with bulky para-substituents (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 3157-3163 
    Details
    ISSN: 0887-624X
    Keywords: poly(phenylacetylene) ; transition metal catalyst ; metathesis polymerization ; geometric structure ; gas permeability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phenylacetylenes (PAs) with bulky substituents (adamantyl, tert-butyl, and n-butyl groups) at the para-position polymerized in good yields with Fe, Rh, Mo, and W catalysts. The formed polymers were soluble, and their number-average molecular weights were in the range of thousands to hundred thousands. Whereas it is known that the poly(PA) obtained with the Fe catalyst is an insoluble cis-cisoidal polymer, the present polymers formed with the same catalyst were totally soluble in many solvents such as benzene and CHCl3. The 1H- and 13C-NMR and DSC data revealed that both of the polymers formed with the Fe and Rh catalysts had virtually all-cis structures, while those with the Mo and W catalysts had cis-rich and trans-rich structures, respectively. Cis-cisoidal and cis-transoidal structures of para-substituted poly(PAs) could not be distinguished because of their good solubility. The bulky substituents raised the temperature of cis-trans isomerization and improved the thermal stability of the polymers. Poly(p-t-BuPA) showed gas permeability higher than that of poly(PA). © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3157-3163, 1998
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    A positive-working photosensitive alkaline-developable polyimide with a highly dimensional stability and low dielectric constant based on poly(amic acid) as a polyimide precursor and diazonaphthoquinone as a photosensitive compound (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 3197-3197 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
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    Tributylstannylated silicic acid as precursor of organofunctionalized silica gel (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 655-663 
    Details
    ISSN: 0887-624X
    Keywords: water glass ; bis(tributyltin)oxide ; tributylstannylated silicic acid ; functionalized silica gel ; silane coupling agent ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tributylstannylated silicic acid (TBSA), which was regarded as a protected polymeric silanol against self-condensation to give silica gel, was newly prepared from the reaction of water glass (WG) and bis(tributyltin) oxide (TBO). The ratios of Si/Sn contained in TBSA were determined by gravimetric analysis to be in the range of 2-3. The gelation of TBSA in usual organic solvents such as hexane, benzene, and dichloromethane was not observed over 3 weeks. In addition, TBSA was shown to be a convenient precursor for the preparations of silica gel modified with organofunctional groups. From the reaction of TBSA with trimethoxysilanes and aromatic alcohols, the silica gels havingorganofunctional groups were obtained with the elimination of a tributyltin group. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 655-663, 1998
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    Convenient approach to novel functional substituted and branched poly(silylenemethylenes) (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 725-735 
    Details
    ISSN: 0887-624X
    Keywords: organosilicon polymer ; poly(silylenemethylene) ; silyl triflate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel poly(silylenemethylenes) have been prepared by the ring-opening polymerization of 1,3-disilacyclobutanes followed by a protodesilylation reaction with triflic acid. The silicon-aryl bond cleavage could be controlled by using different leaving groups, for instance phenyl- and para-anisyl substituents. The reactions of the triflate derivatives with organomagnesium compounds, LiAlH4, amines, or alcohols gave functional substituted poly(silylenemethylenes). Hydrosilylation reactions or reductive coupling with potassium-graphite led to organosilicon network-polymers, which may serve as suitable precursors for silicon carbide and Si/C/N-based materials. The structures of the polymers were identified by NMR spectroscopy (29Si, 13C, 1H). © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 725-735, 1998
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    Synthesis, homopolymerization, and block copolymerization of N-ethyl-2-ethynyl-pyridinium trifluoromethanesulfonate with styrene and butadiene (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 703-712 
    Details
    ISSN: 0887-624X
    Keywords: synthesis ; homopolymerization ; block copolymerization ; N-ethyl-2-ethyl-pyridinium ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel acetylenic monomer 2-N-ethyl pyridinium trifluoromethane sulfonate (2EPyEtTf) was synthesized and polymerized. Diblock copolymers of 2EPyEtTf with styrene and with butadiene were prepared. Initiation of the polymerization by living anionic polystyryl--Li+ and polybutadienyl--Li+ (Scheme 1) resulted in polystyrene-block-poly(N-ethyl-2-ethynylpyridinium trifluoromethanesulfonate) (PS57PA8), and polybutadiene -block-poly(N-ethyl-2-ethynylpyridinium trifluoromethanesulfonate) (PB30PA8). These amphiphilic block molecules contain rigid, conjugated, and strongly hydrophilic polyacetylene chain fragments attached to hydrophobic polystyrene or flexible polybutadiene chain fragments. The structure of these copolymers was studied by FTIR, UV-visible, and NMR spectroscopy. GPC and viscometry were also used to obtain information on the molecular mass and the molecular mass distribution. Thermal behavior was investigated by means of TGA and DSC. Both block copolymers were shown to form stable monolayers at the air-water interface. The positively charged rigid polyacetylene portion of the copolymer is believed to be partially submerged, while the more flexible hydrophobic chains are forced out of the water. Multilayers of PB30PA8 deposited using the Langmuir-Blodgett technique were found to be less uniform than in the case of the previously reported polystyrene-block-poly(2EPyMeTf) (PS12PA4) copolymer (Balogh et al., Macromolecules, 29, 1996). Polycation-polyanion self-assembly deposition was also investigated, using polystyrenesulfonate (PSS) as polyanion. While PS57PA8/PSS layer-by-layer deposition was not uniform, it was found that PB30PA8/PSS gave homogenous and stable films on hydrophilic glass substrates. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 703-712, 1998
    Additional Material: 8 Ill.
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    New aromatic benzazole polymers II: Synthesis and conductivity of benzobisthiazole-co-polymers incorporated with 4-N,N-dimethylaminotriphenylamine groups (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 713-724 
    Details
    ISSN: 0887-624X
    Keywords: poly(benzobisthiazole) ; copolymers ; 4-N,N-dimethylaminotriphenylamine ; conducting polymers ; iodine doping ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New aromatic benzobisthiazole copolymers containing 10-70 mol % of 4-N,N-dimethylamino-triphenylamine functionality were prepared from the respective dinitrile or dicarboxylic acid monomers, terephthalic acid, and 2,5-diamino-1,4-benzene-dithiol dihydrochloride in polyphosphoric acid. At the first approximation, the copolymers containing 10 mol % or less of the triarylamino moieties in the polymer chains still preserve the capability to form anisotropic (nematic) solutions at 10 wt % polymer concentration. This is an important requirement for processing the copolymers into fibers and films with good to excellent mechanical properties. Films with good mechanical integrity were cast from the dilute methanesulfonic acid solutions of the copolymers under reduced pressure. They showed electrical conductivity values of the order of 10-11-10-10 S/cm in pristine state, with four to seven orders of magnitude increase upon exposure to mild oxidizing agents such as iodine vapor. On the contrary, the parent polymer, poly(p-phenylene benzobisthiazole) is an insulator with conductivity of less than 10-12 S/cm, and its conductivity does not improve at all with exposure to iodine vapor. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 713-724, 1998
    Additional Material: 6 Ill.
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    Synthesis, liquid crystallinity, and mechanical properties of thermotropic polyquinolines (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 749-759 
    Details
    ISSN: 0887-624X
    Keywords: polyquinoline ; liquid crystalline polymer ; thermotropic ; mechanical property ; substituted polyquinoline ; flexible groups ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermotropic liquid-crystalline polyquinolines with high molecular weights, i.e., poly[2,2′-(α,ω-dioxyphenylene (or -dioxybiphenylene) alkane)-6,6′-(4,4′-dioxybiphenyl)-bis(4-phenylquinoline)]s (P-H-B1Mns or P-H-B2Mns), were synthesized by polycondensation of 4,4′-bis(4-amino-3-benzoylphenoxy)biphenyl and α,ω-bis(4-acetophenoxy (or -acetobiphenoxy))alkanes. For P-H-B1Mn series, the Tm and Ti were in the range of 129-230°C and 156-254°C, respectively, while for the P-H-B2Mn series, those were 182-275°C and 217-309°C, respectively. The introduction of both the dioxybiphenylene group and an alkylene spacer induced thermotropic liquid crystallinity in the polyquinoline, although the introduction of the alkylene spacer alone did not induce it. In addition, polyquinolines substituted with methyl, methoxy, and chloro groups exhibited larger mesophase temperature ranges as well as higher Tms and Tis than the unsubstituted ones. Tensile strengths of these thermotropic polyquinolines were considerably high in the range of 770 to 1170 kgf/cm2. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 749-759, 1998
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    Controlled free radical ring-opening polymerization and chain extension of the “living” polymer (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 761-771 
    Details
    ISSN: 0887-624X
    Keywords: ring-opening polymerization ; “living” free radical polymerization ; stable free radical ; 2-methylene-1,3-dioxepane ; 2,2,6,6-tetramethyl-1-piperidinyloxy free radical ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Free radical ring-opening polymerization of 2-methylene-1,3-dioxepane (MDP) in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy free radical (TEMPO) has been achieved to afford a chain polyester (PMDP) with di-t-butyl peroxide (DTBP) as an initiator at 125°C. The polydispersity of the polymers decreases as the concentration of TEMPO is increased. At high TEMPO concentrations, the polydispersity as low as 1.2 was obtained, which is below the theoretical lower limit for a conventional free radical polymerization. A linear relationship between the number-average molecular weight (Mn) and the monomer conversion was observed with the best-fit line passing very close to the origin of the Mn-conversion plot. The isolated and purified TEMPO-capped PMDP polymers have been employed to prepare chain extended polymers upon addition of more MDP monomer. These results are suggestive of the “living” polymerization process. A possible polymerization mechanism might involve thermal homolysis of the TEMPO-PMDP bonds followed by the addition of the monomers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 761-771, 1998
    Additional Material: 3 Ill.
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    Curing reaction of biphenyl epoxy resin with different phenolic functional hardeners (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 773-783 
    Details
    ISSN: 0887-624X
    Keywords: biphenyl epoxy ; hardener ; cure kinetics ; cure mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The investigation of cure kinetics and relationships between glass transition temperature and conversion of biphenyl epoxy resin (4,4′-diglycidyloxy-3,3′,5,5′-tetramethyl biphenyl) with different phenolic hardeners was performed by differential scanning calorimeter using an isothermal approach over the temperature range 120-150°C. All kinetic parameters of the curing reaction including the reaction order, activation energy, and rate constant were calculated and reported. The results indicate that the curing reaction of formulations using xylok and dicyclopentadiene type phenolic resins (DCPDP) as hardeners proceeds through a first-order kinetic mechanism, whereas the curing reaction of formulations using phenol novolac as a hardener goes through an autocatalytic kinetic mechanism. The differences of curing reaction with the change of hardener in biphenyl epoxy resin systems were explained with the relationships between Tg and reaction conversion using the DiBenedetto equation. A detailed cure mechanism in biphenyl-type epoxy resin with the different hardeners has been suggested. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 773-783, 1998
    Additional Material: 8 Ill.
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    Synthesis and properties of poly(oxyethylene)s containing thioether, sulfoxide, or sulfone groups (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 793-801 
    Details
    ISSN: 0887-624X
    Keywords: poly(oxyethylene) ; thioether ; sulfoxide ; sulfone ; copolymer ; solubility ; glass transition temperature ; substitution ; oxidation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly[oxy(ethylthiomethyl)ethylene] (ETE) was prepared from poly[oxy (chloromethyl)ethylene] (CE) by reaction with sodium ethanethiolate. Sulfoxide and sulfone analogues were synthesized by oxidation of the poly[oxy(ethylthiomethyl)ethylene]. By changing the chloromethyl/sodium ethanethiolate ratio, poly[oxy (chloromethyl)ethylene-co-oxy(ethylthiomethyl)ethylene] (CE-ETEs) were easily made. Poly[oxy(ethylsulfinylmethyl)ethylene] (ESXE), poly[oxy(chloromethyl)ethylene-co-oxy(ethylsulfinylmethyl)ethylene] (CE-ESXEs), poly[oxy(ethylsulfonylmethyl)ethylene] (ESE), and poly[oxy(chloromethyl)ethylene-co-oxy(ethylsulfonylmethyl)ethylene] (CE-ESEs) were obtained by oxidation of ETE or CE-ETEs. There was little if any chain degradation. The (co)polymer structures were confirmed by FTIR and 1H-NMR spectroscopic studies. Their thermal properties were studied by DSC and TGA. Tgs of ETE, ESXE, and ESE were -57, 36, and 57°C, respectively, and Td,os (initial decomposition temperature, TGA) were 331, 198, and 308°C, respectively. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 793-801, 1998
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    Graft copolymers prepared by ethoxylation of polyamide 12 and poly(ethylene-co-vinyl alcohol) (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 803-811 
    Details
    ISSN: 0887-624X
    Keywords: grafting ; poly(amide-graft-ethylene oxide) ; poly(ethylene-co-vinyl alcohol-graft-ethylene oxide) ; ethoxylation ; anionic polymerization of ethylene oxide ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Graft copolymers consisting of polyamide 12 or poly(ethylene-co-vinyl alcohol) as backbone polymers and side chains of poly(ethylene oxide) have been synthesized. The amide and hydroxyl groups of the backbone polymers were used as initiation sites for the polymerization of ethylene oxide (EO). Potassium tert-butoxide was used for ionization of the active groups, and the polymerization of EO was carried out in dimethyl sulfoxide. The graft copolymers were characterized with respect to molecular weight and composition using elemental analysis, 1H-NMR, gel permeation chromatography, and FTIR. The size of the side chains varied between 300 and 1000 g/mol. Thermal properties were examined by DSC. The graft copolymers showed increasing crystallinity and increasing melt temperature with increasing molecular weight of the side chains. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 803-811, 1998
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    Synthesis and characterization of new polyamides containing adamantyl and diamantyl moieties in the main chain (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 785-792 
    Details
    ISSN: 0887-624X
    Keywords: polyamides ; adamantane ; diamantane ; synthesis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This work synthesized a series of new polyamides by direct polycondensation of 1,3-bis[4-(4-carboxyphenoxy)phenyl]adamantane (I) with various diamines. The diacid I was synthesized from 1,3-bis(4-hydroxyphenyl)adamantane in two steps. Polyamides III were soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and pyridine. The polyamides had medium inherent viscosities of 0.30-0.55 dL/g and number-average molecular weights (Mn) of 22,000-36,000. The polyamides IIIa and IIIb had tensile strengths of 59.8 and 77.5 MPa, elongation to breakage values of 5.8 and 7.6%, and initial moduli of 1.9 and 1.8 GPa, respectively. Their glass transition temperatures were found to be 219-295°C by means of differential scanning calorimetry (DSC). Dynamic mechanical analysis (DMA) reveals that the incorporation of rigid and bulky diamantane into polyamides IIIa and IIIb leads to high glass transition temperatures (Tgs), at 299 and 286°C, respectively. The decomposition temperatures of polyamides III at a 5% weight loss ranged from 388 to 416°C in air and from 408 to 435°C in N2 atmosphere. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 785-792, 1998
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    Case studies and literature review on the estimation of copolymerization reactivity ratios (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 813-822 
    Details
    ISSN: 0887-624X
    Keywords: copolymerization reactivity ratios ; RREVM ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enhanced features of a computer program (RREVM) for the estimation of copolymerization reactivity ratios using statistically sound techniques are illustrated with experimental and simulated case studies. In parallel, a literature review is given on the estimation of reactivity ratios. Both aspects are extensions based on the articles by Dube et al.1 and Rossignoli and Duever.2 © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 813-822, 1998
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    Synthesis and properties of poly(amide-imide)s based on the diimide-diacid condensed from 2,2′- bis(4-aminophenoxy)biphenyl and trimellitic anhydride (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1169-1177 
    Details
    ISSN: 0887-624X
    Keywords: poly(amide-imide)s ; 2,2′-bis(4-trimellitimidophenoxy) biphenyl ; solubility ; 2,2′-bis(4-aminophenoxy)biphenyl ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new dicarboxylic acid having a kinked structure was synthesized from the condensation of 2,2′-bis(4-aminophenoxy)biphenyl and trimellitic anhydride. A series of biphenyl-2,2′-diyl-containing aromatic poly(amide-imide)s having inherent viscosities of 0.23-0.94 dL/g was prepared by the triphenyl phosphite activated polycondensation from the diimide-diacid II with various aromatic diamines in a medium consisting of N-methyl-2-pyrrolidone (NMP), pyridine, and calcium chloride. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including NMP and N,N-dimethylacetamide (DMAc). Transparent, flexible, and tough films of these polymers could be cast from DMAc or NMP solutions. The glass transition temperatures of these polymers were in the range of 227-261°C and the 10% weight loss temperatures were above 520°C in nitrogen. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1169-1177, 1998
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    Hydrogels by atom transfer radical polymerization. I. Poly(N-vinylpyrrolidinone-g-styrene) via the macromonomer method (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 823-830 
    Details
    ISSN: 0887-624X
    Keywords: atom transfer radical polymerization ; poly(N-vinylpyrrolidinone-g-styrene) ; macromonomer method ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Atom transfer radical polymerization has been used to prepare well-defined vinyl macromonomers of polystyrene using vinyl chloroacetate as an initiator. Because styrene and vinyl chloroacetate do not copolymerize, no branching or incorporation of the initiator into the backbone was observed. Macromonomers of several molecular weights were prepared and copolymerized free radically with N-vinylpyrrolidinone in varying feed ratios in order to produce poly(NVP-g-Sty) graft copolymers. The macromonomers used were of sufficiently high molecular weight to form physical crosslinks in solvents which favor the hydrophilic NVP, such as water, which prevent the copolymer from dissolving and cause it to swell. These materials, therefore, formed hydrogels of swellabilities in water exceeding 95%, depending on the amount of styrene that was incorporated into the copolymer. Limitations of and alternatives to this method are also discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 823-830, 1998
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    Cationic copolymerization of cyclic ketene acetals: The effect of substituents on reactivity (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 861-871 
    Details
    ISSN: 0887-624X
    Keywords: 2-methylene-1,3-dioxane ; 4-methyl-2-methylene-1,3-dioxane ; 4,4,6-trimethyl-2-methylene-1,3-dioxane ; 2-methylene-1,3-dioxolane ; 4-methyl-2-methylene-1,3-dioxolane ; 4,5-dimethyl-2-methylene-1,3-dioxolane ; cationic copolymerization ; reactivity ratio ; relative reactivity ; ring-retained polymerization ; cyclic ketene acetals ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic copolymerizations of 4-methyl-2-methylene-1,3-dioxane, 2 (M1), with 2-methylene-1,3-dioxane, 1 (M2); of 4,4,6-trimethyl-2-methylene-1,3-dioxane, 3 (M1), with 2-methylene-1,3-dioxane, 1 (M2); of 4-methyl-2-methylene-1,3-dioxolane, 5 (M1), with 2-methylene-1,3-dioxolane, 4 (M2); and of 4,5-dimethyl-2-methylene-1,3-dioxolane, 6 (M1), with 2-methylene-1,3-dioxolane, 4 (M2) were conducted. The reactivity ratios for these four types of copolymerizations were r1 = 1.73 and r2 = 0.846; r1 = 2.26 and r2 = 0.310; r1 = 1.28 and r2 = 0.825; r1 = 2.23 and r2 = 0.515, respectively. The relative reactivities of these monomers towards cationic polymerization are: 3 〉 2 〉 1; and 6 〉 5 〉 4. With both five- and six-membered ring cyclic ketene acetals, the reactivity increased with increasing methyl substitution on the ring. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 861-871, 1998
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    Preparation and absorption spectrum studies of aromatic and alicyclic poly(amide acid) ammonium salts in water and DMF and in films (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1329-1340 
    Details
    ISSN: 0887-624X
    Keywords: poly(amide acid) ammonium salts ; poly(amide acid)s ; water-soluble polyimide precursors ; UV-vis absorption spectra ; charge transfer ; solubility ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of ammonium salts of poly(amide acid)s (PAS) were prepared from various poly(amide acid)s (PAA) with tertiary amines. The solubility of poly(amide acid) ammonium salts prepared from PAA(PMDA/ODA) in water is related to the ion concentration of tertiary amines. In order to elucidate the influence of the chemical structures of poly(amide acid)s and poly(amide acid) ammonium salts on their absorption spectra, pyromellitic dianhydride (PMDA), 3,3′,4,4 ′-biphenyltetracarboxylic dianhydride (BPDA), and 3,3′,4,4 ′-benzophenonetetracarboxylic dianhydride (BTDA) were chosen to react with p-phenylenediamine (PDA) and (4,4′-diaminodicyclohexyl)methane (DCHM) to give three kinds of aromatic PAAs and three kinds of alicyclic PAAs. The corresponding PASs were prepared by the reaction of PAAs with triethanolamine (TEA). Their ultraviolet-visible (UV-vis) absorption spectra were investigated compared to those of model compounds. A transparent film without absorption above 320 nm was obtained for PAS(PMDA/DCHM). The difference in absorption spectra of PAS(PMDA/PDA) from that of PAS(PMDA/DCHM) can be related to the existence of intra- and intermolecular charge transfer (CT) for PAS(PMDA/PDA). The absorption spectra of PASs with PDA in films are red shifted compared to those of corresponding PAAs in films, while the absorption spectra of PASs in water are blue shifted compared to those of corresponding PAAs in DMF. No differences in the absorption spectra of PAAs and PASs were found in DMF/H2O (9/1) mixed solvent. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1329-1340, 1998
    Additional Material: 8 Ill.
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  • 192
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    Polyurethanes crosslinked by metals and their complexes with crown ether (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1379-1386 
    Details
    ISSN: 0887-624X
    Keywords: polyrethanes ; crown ether ; metal complexes ; X-ray scattering ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two types of crosslinked polyurethanes (PU) have been synthesized: (a) PU crosslinked by metal ions (Cu2+ and Co2+), and (b) PU crosslinked by the complexes of metals with crown ether. Using X-ray scattering under small and wide angles the peculiarities of the structure of networks have been investigated. It was found that PU crosslinked by the metal crown ether complexes have a looser structure because of the bulky crosslink and diminished molecular mobility of the chains between two crosslinks, as was proven by the dielectric spectroscopy method. The X-ray and IR data have allowed proposing a scheme of the structure of the crosslinked PU with various types of crosslinks. The structures discovered may be considered as similar to metal catenandes. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1379-1386, 1998
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  • 193
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    New polymer syntheses. XCVI. Star-shaped LC-polyesters derived from β-(4-hydroxyphenyl)propionic acid and 4-hydroxybenzoic acid (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1387-1395 
    Details
    ISSN: 0887-624X
    Keywords: star-shaped polyesters ; nematic phase ; phloritic acid ; spirobis indane ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Star-shaped polyesters were prepared by polycondensation of tetraacetoxyspirobis(indane) and a 1 : 1 mixture of silylated β-(4-acetoxyphenyl)propionic acid and silylated 4-acetoxybenzoic acid. The lengths of the star arms were systematically varied, and the influence of the star center on the stability of the nematic phase was studied. It was found that on the average more than 10 monomer units per star arm are required to stabilize a homogeneous LC-phase. Furthermore, a second class of star-shaped polyesters consisting of β-(4-hydroxyphenyl)propionic acid (HPPA), 4-hydroxybenzoic acid (HBA), and 6-hydroxy-2-naphthoic acid (HNA) was prepared. This ternary copolyester proved to reduce the crystallinity but to stabilize the LC-character. A homogeneous nematic melt was obtained with 6 monomer units per star arm. This interpretation is based on optical microscopy which provides a static picture of the biphasic situation. Therefore, a preliminary study of the melt rheology was included, which proved that the typical LC-character of the melt was detectable ateven shorter star arms due to the shear orientation. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1387-1395, 1998
    Additional Material: 7 Ill.
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  • 194
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    Structural effect of polymeric acid dopants on the characteristics of doped polyaniline composites: Effect of hydrogen bonding (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1431-1439 
    Details
    ISSN: 0887-624X
    Keywords: polyaniline ; polymeric acid dopant ; conducting polymer ; doping level ; chain alignment ; conductivity ; hydrogen bonding ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conductivities of polyaniline (PANi) composites doped with the copolymeric acids such as poly(methyl methacrylate-co-p-styrenesulfonic acid) (PMMA-co-SSA), poly(styrene-co-p-styrenesulfonic acid) (PS-co-SSA), and poly(methyl methacrylate-co-2-acrylamido-2-methyl-1-propanesulfonic acid) (PMMA-co-AMPS) were investigated as a function of the acid content in the copolymeric acid dopants. With the fixed ratio of acid to aniline (1/1) in the PANi composites, the conductivities of the copolymeric acid-doped PANis decreased as the acid content in the copolymeric acids decreased. This could be attributed to the nonacidic units in the copolymeric acids which seemed to prevent adjacent acid groups from doping the PANi. Among the three kinds of copolymeric acid dopants, the PMMA-co-SSA series doped the PANi most effectively, and consequently, the PMMA-co-SSA-doped PANi composites showed the highest conductivities. The lack of conductivities of the PMMA-co-AMPS-doped PANi composites seems to be due to the doping ability of the AMPS groups. The higher conductivities of the PMMA-co-SSA-doped PANi composites rather than the PS-co-SSA-doped ones were attributed to the hydrogen bonding formed between the carbonyl groups in MMA and the amine groups in aniline which may hinder the phase separation and induce more homogeneous mixing and efficient doping. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1431-1439, 1998
    Additional Material: 8 Ill.
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  • 195
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    Synthesis and spinning of a thermotropic liquid crystal copolyester containing a semirigid cycloaliphatic spacer (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1473-1480 
    Details
    ISSN: 0887-624X
    Keywords: thermotropic polymers ; liquid crystalline polymers ; semirigid spacers ; melt spinning ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A thermotropic, liquid crystalline copolyester, based on 2-chlorohydroquinone, 1,4-cyclohexanedimethanol and terephthaloyl chloride, has been synthesized and melt spun. The cyclohexanedimethylene moiety acts as a semirigid spacer, introducing flexibility while preserving the thermotropic nature of the polymer. Melt-spun fibers were observed to have a high degree of molecular alignment owing to the nematic nature of the melt. Both polymer and fiber properties have been characterized. Characterization techniques used to this end include elemental analysis, hot-stage polarized light microscopy, scanning electron microscopy, dilute solution viscometry, Fourier transform infrared spectroscopy, nuclear magnetic resonance, differential scanning calorimetry, and thermogravimetric analysis. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1473-1480, 1998
    Additional Material: 9 Ill.
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  • 196
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    Synthesis and properties of copolymers from 2-hydroxyethyl methacrylate-linked nonsteroidal antiinflammatory agents with methacrylic acid (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1481-1490 
    Details
    ISSN: 0887-624X
    Keywords: ibuprofen ; ketoprofen ; naproxen ; copolymer reactivity ; thermal stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three nonsteroidal antiinflammatory drugs, 2-(4-isobutylphenyl)-propionic acid (ibuprofen), 2-(3-benzoylphenyl)-propionic acid (ketoprofen), and 2-(6-methoxy-2-naphthyl)-propionic acid (naproxen), were covalently linked with 2-hydroxyethyl methacrylate (HEMA). The drug-linked HEMA (M1) (ibuprofen-linked HEMA abbreviated as HI; ketoprofen-linked HEMA as HK, and naproxen-linked HEMA as HN), were respectively copolymerized with methacrylic acid (M2), MA, to obtain macromolecular prodrugs. The compositions of the copolymers were determined by means of a 1H-NMR spectroscopy and monomer reactivity ratios were estimated using the Kelen-Tüdös linear differential equation. The reactivity ratios are: r1 = 0.101 ± 0.012, r2 = 1.071 ± 0.065 for HI-MA; r1 = 0.344 ± 0.066, r2 = 0.966 ± 0.032 for HN-MA, and r1 = 0.650 ± 0.182, r2 = 1.032 ± 0.106 for HK-MA, respectively. The monomer reactivity toward to MA radical estimated from 1/r2 values is almost same for all three monomers (1/r2 ∼ 1). The glass transition temperatures of three drug-linked homopolymers go hand in hand with the steric hindrance of three drugs, i.e., ketoprofen 〉 naproxen ≫ ibuprofen calculated the minimum energy by computer molecular modeling. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1481-1490, 1998
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  • 197
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    Synthesis and radical polymerization of a vinyl monomer having a sulfonylacylurea moiety and hydrolysis of the obtained polymer (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1515-1519 
    Details
    ISSN: 0887-624X
    Keywords: sulfonyl isocyanate ; acrylamide ; sulfonylurea ; radical polymerization ; hydrolysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radical polymerization of N-acryloyl-N′-(p-tolylsulfonyl)urea (2), prepared easily by the reaction of p-toluenesulfonyl isocyanate with acrylamide, was carried out in DMF, DMSO, or NMP at 60°C by use of AIBN as an initiator to give a polymer 3 in a good yield. Copolymerization parameters of 2 were evaluated by the copolymerization with MMA. Polymer 3 was readily hydrolyzed in an aqueous NaOH solution (1M) at room temperature to give poly(acrylic acid). The reason for the higher activity for hydrolysis of 3 compared to an ordinary amide is discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1515-1519, 1998
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  • 198
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    Sequence distributions versus catalyst site behavior of in situ blends of polypropylene and poly(ethylene-co-propylene) (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1527-1542 
    Details
    ISSN: 0887-624X
    Keywords: high-impact polypropylenes ; 13C-NMR ; Markovian statistics ; reactivity ratio product ; catalyst site distribution ; sequence distributions ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sequential polymerizations of first propylene and then ethylene, propylene mixtures with the same Ziegler-Natta catalyst system produce in situ blends known as high-impact polypropylenes. Over 100 high-impact polypropylenes are characterized in terms of weight fractions and sequence distributions for isotactic polypropylene, atactic polypropylene, an amorphous ethylene propylene copolymer, and a crystalline ethylene propylene copolymer. The apparent r1r2 behaviors of the E/P copolymers suggest that the amorphous and crystalline E/P copolymers principally arise from different types of catalyst sites as opposed to originating strictly from compositional heterogeneities. The amorphous copolymers consistently have r1r2 values close to unity over a broad range of compositions, while the corresponding crystalline copolymers have apparent r1r2 values that range from 2 to over 20. An apparent r1r2 close to unity not only reflects random sequencing but also indicates a narrow compositional distribution. This r1r2 result indicates that the amorphous E/P copolymers are produced from a singular type of catalyst site. The higher r1r2 values shown by the crystalline E/P copolymers indicate broad compositional distributions that are produced by a different type or types of catalyst sites. The ratio of amorphous to crystalline ethylene, propylene copolymers is nominally around 80/20 over a broad range of impact copolymer compositions. The consistency of this result suggests that the two basic types of catalyst sites producing E/P copolymers are also in an approximate 80/20 ratio. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1527-1542, 1998
    Additional Material: 6 Ill.
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    Optical emission diagnostics in cascade arc plasma polymerization and surface modification processes (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1583-1592 
    Details
    ISSN: 0887-624X
    Keywords: optical emission spectroscopy ; cascade arc ; surface modification ; fluorination ; plasma polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical Emission Spectroscopy (OES) was used to identify reactive species and their excitation states in low-temperature cascade arc plasmas of N2, CF4, C2F4, CH4, and CH3OH. In a cascade arc plasma, the plasma gas (argon or helium) was excited in the cascade arc generator and injected into a reactor in vacuum. A reactive gas was injected into the cascade arc torch (CAT) that was expanding in the reactor. What kind of species of a reactive gas, for example, nitrogen, are created in the reactor is dependent on the electronic energy levels of the plasma gas in the cascade arc plasma jet. OES revealed that no ion of nitrogen was found when argon was used as the plasma gas of which metastable species had energy less than the ionization energy of nitrogen. When helium was used, ions of nitrogen were found. While OES is a powerful tool to identify the products of the cascade arc generation (activation process), it is less useful to identify the reactive species that are responsible for surface modification of polymers and also for plasma polymerization. The plasma surface modification and plasma polymerization are deactivation processes that cannot be identified by photoemission, which is also a deactivation process. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1583-1592, 1998
    Additional Material: 12 Ill.
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  • 200
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    Unbridged bivalent lanthanidocenes for isotactic and stereomultiblock polymerization of methyl methacrylate (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1599-1606 
    Details
    ISSN: 0887-624X
    Keywords: bivalent organolanthanides ; polymerization ; methyl methacrylate ; stereomultiblock polymer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bivalent organolanthanides with unbridged substituted indenyl or fluorenyl ligands (1-SiMe3Ind)2YTHF (I), (9-SiMe3Flu)2YTHF (II), were found to efficiently catalyze the stereoregular polymerization of methyl methacrylate. The microstructure of resultant polymers was shown to be dependent of a conformation that the ligands adopt at the polymerization temperature. The formation of isotactic rich PMMAs from complex II was proposed to be associated with the fluctuation of the 9-trimethylsilylfluorenyls around a C2 symmetric twisted-conformation. The formation of the multi(syndioPMMA-block-iso-PMMA) polymers from the mixture of rac- and meso-isomers of I was rationalized on the basis of competing conjugate addition and inversion of the metallocene conformation. Surprisingly, both rac- and meso-isomers of I were found to operate with similar activity and stereospecifity, although the stereospecific operation of the meso-form was not completely understandable. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1599-1606, 1998
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