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  • Articles: DFG German National Licenses  (5,223)
  • 1995-1999  (5,223)
  • 1995  (5,223)
  • Polymer and Materials Science  (4,710)
  • Computational Chemistry and Molecular Modeling  (513)
  • Nuclear reactions
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  • Articles: DFG German National Licenses  (5,223)
Material
Years
  • 1995-1999  (5,223)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 7-13 
    ISSN: 0887-624X
    Keywords: radical terpolymerization ; charge transfer complexes ; phenanthrene ; maleic anhydride ; trans-stilbene ; thermal stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radical terpolymerization of the donor-acceptor-donor monomer system, phenanthrene (P) - maleic anhydride (M) - trans-stilbene (S), was studied. These monomers are known to be nonhomopolymerizable. The terpolymerization was carried out in p-dioxane and/or toluene at 70°C in the presence of benzoyl peroxide used as the initiator. P and S were found to form charge transfer complexes (CTC) with M in p-dioxane at 35°C. The results obtained are discussed in terms of the free monomer and complex propagation models. It is shown that terpolymerization is carried out at a stage close to binary copolymerization of two complexomers. The reactivity ratio of P … M and S … M complexes was estimated by the Kelen-Tüdös method. Absorbance ratios at 1770 cm-1 (vC=0 of anhydride group), 764 cm-1 (δCH in monosubstituted benzene of S), and 820 cm-1 (δCH in disubstituted benzene of P) as a function of terpolymer composition were established. P - M - S terpolymers are shown to have high thermal stabilities. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1375-1380 
    ISSN: 0887-624X
    Keywords: poly(vinyl chloride) ; electrical conductivity ; photodehydrochlorination ; laminated films ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(vinyl chloride) (PVC) has been converted to an electrically conductive structure by combined electrochemical and photochemical methods. PVC was cast on a polypyrrole (PPy) film electrode which had been electrochemically prepared. The PVC layer in the laminated PVC/PPy films was first dehydrochlorinated under the illumination of UV light, and the generated polyenes were subsequently doped with I2 and FeCl3. The maximum electrical conductivity achieved for such PVC film was 2.51 X 10-2 and 8.63 10-2 S cm-1 after I2 and FeCl3 doping, respectively. The temperature dependence of the electrical conductivity showed different behavior in higher and lower temperature ranges. In the former (T 〉 243 K), the T-1 law held, and the activation energy and bandgap were estimated as 0.25 and 0.49 eV, respectively. In the latter (T 〈 243 K), the conductivity mechanism followed the variable range hopping model (T-1/4 law) in which the radius of the localized state wave function and the density of the localized states at the Fermi level were 1.25 × 103 Å and 1.03 X 1015 eV-1 cm-3, respectively. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1409-1417 
    ISSN: 0887-624X
    Keywords: emulsion polymerization ; oligomers ; polystyrene ; hydrotalcite ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dominant species in the early stages of an emulsifier-free emulsion polymerization of styrene has been found to be an oligomer of two to three monomer units using a novel trapping technique. This involved the intercalation of charged primary oligomers between the layers of a hydrotalcite, [Mg4Al2(OH)12]2+[A]2- (where A = dianion). Hydrotalcites are an important class of lamellar, inorganic compounds whose interlayer spacing can be mod-ified by anion exchange. Our approach first involved preparing a hydrotalcite precursor in which the layers were propped apart by an organic dianion (terephthalate = TA). This material was then used to capture the negatively charged polystyrene oligomers from the emulsion polymerization reaction mixture. We found that TA was rapidly ion-exchanged for the charged oligomers.The resulting pillared hydrotalcite material was characterized using XRD and SEC. We found that the interlayer spacing between the hydroxide layers increased to 23.2 Å on exposure to the emulsion reaction mixture. This represents an interlayer expansion of 18.3 Å (after subtraction of the hydroxide layer contribution), which is cnsistent with intercalation of oligomers with two to three monomer units arranged in a bilayer. This size estimate was confirmed by the results of size exclusion chromatography. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1455-1460 
    ISSN: 0887-624X
    Keywords: γ-oxidation ; polyethylene ; FTIR ; molecular weight ; elongation at break ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: γ-Oxidation of linear low-density polyethylene based on hexene and butene was investigated. Irradiation was performed at different dose rates in air (from 2 rad/s to 100 rad/s). Degraded samples were analyzed with IR combined with NO and SF4 derivatizations. Our results showed that the lower the dose rate, the higher the degree of oxidation in terms of γ-product formation. Ketone species appeared to be the dominant γ-products. The G values of γ-product formation were very dependent on the dose rate of initiation. Comparison of the G value ratio of different γ-products revealed stoechiometry differences. The complex appearance and disappearance of unsaturations was tentatively explained. The modifications of elongation at break induced by γ-irradiation were monitored by molecular changes in weight. This was not conclusive because changes in elongation at break are inconsistent with changes in Mw/Mn. © 1995 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1465-1474 
    ISSN: 0887-624X
    Keywords: grafting ; poly(styrene-graft-ethylene oxide) ; styrene-oxirane graft copolymers ; ethoxylation ; alkylation ; anionic polymerization of ethylene oxide ; poly(styrene-co-acryl-amide) ; crystallinity ; water absorption ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(styrene-graft-ethylene oxide), having alkyl chains (C12 or C18) on the polystyrene main chain or on the poly(ethylene oxide) (PEO) side chains, were synthesized. The main chain was alkylated by first ionizing amide groups in a styrene/acrylamide copolymer with tert-butoxide, and then using the amide anions as sites for reactions with 1-bromoalkanes. An excess of amide anions was used in the reaction, and the remaining anions were subsequently utilized as initiator sites for the anionic polymerization of ethylene oxide (EO). Synthesis of poly(styrene-graft-ethylene oxide) with alkylated side chains was accomplished by polymerization of EO onto the ionized styrene/acrylamide copolymer, followed by an alkylation of the terminal alkoxide anions with 1-bromoalkanes. The alkylated graft copolymers were structurally characterized by using elemental analysis, 1H NMR, GPC, and IR spectroscopy. DSC analysis showed that only graft copolymers with PEO contents exceeding about 50 wt % and side chain crystallinities comparable to those of homo-PEO. Main chain alkylated graft copolymers generally had higher crystalinities, as compared to nonalkylated and side chain alkylated samples. The graft copolymers absorbed water corresponding to one water molecule per EO unit at low PEO contents. The water absorption increased progressively at PEO contents above 30 wt % for main chain alkylated samples and above 50 wt % for non-alkylated samples. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1419-1429 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
    Additional Material: 5 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1447-1454 
    ISSN: 0887-624X
    Keywords: terpolymerization ; charge transfer complex ; allylglycidyl ether ; maleic anhydride ; methyl methacrylate ; thermo-crosslinking ; photo-crosslinking ; thermal degradation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical copolymerization of donor-acceptor monomers, i.e., allylglycidyl ether (AGE), maleic anhydride (MA) and methyl methacrylate (MMA) are studied, where binary copolymerization of AGE...MA complex with MMA is obtained. Constants of charge transfer complex formation (Kc) and copolymerization (r1 and r2) are determined by 1H-NMR and Kelen-Tüdöş methods, respectively. It is found that synthesized film-forming terpolymers with free epoxy and anhydride groups on side chain of macro-molecules are being crosslinked easily under the effect of temperature and/or UV-ir-radiation. Observed crosslinking effect is proved by the DTA, TGA, and IR spectroscopic analyses. It is shown that complex-radical terpolymerization is very convenient method for the designing of reactive functional macromolecules of linear structure with self-crosslinking properties which can serve as a basis for the use in photolithographic applications. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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  • 8
    ISSN: 0887-624X
    Keywords: saccharic acid ; dilactone ; polyaddition ; polyurethane ; diisocyanate ; deg-radation ; hydrolysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyaddition of saccharic acid dilactones prepared from D-glucose and D-mannitol, D-glu-caro-, and D-mannaro-1,4:6,3-dilactones (1 and 2, respectively), with hexamethylene di-isocyanate (3a) and methyl (S)-2,6-diisocyanatocaproate (3b) was carried out by using dibutyltin dilaurate as a catalyst at 50, 25, and 0°C to give polyurethanes (4 and 5) having dilactone moieties in the main chains. The resulting polymers were found to decompose easily in phosphate buffers under neutral or slightly basic conditions (pH 7 or 8). Therefore, the polyurethanes may be used as novel degradable polymeric materials. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 9
    ISSN: 0887-624X
    Keywords: methacrylate bearing donor and acceptor moieties ; polymer effect ; intra-molecular charge-transfer interaction ; spacer length ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-[3,5-Bis(N,N-dimethylamino)phenoxy]-ω-(2,4,6-tricyanophenylthio)alkanes (1a-c), where an electron-accepting 2,4,6-tricyanophenylthio group and an electron-donating 3,5-bis(N,N-dimethylamino)phenoxy one are linked with a spacer such as ethylene, trimethylene, and tetramethylene, were prepared in order to examine an effect of the spacer chain length on intramolecular charge-transfer interaction between the 2,4,6-tricyanophenylthio and 3,5-bis(N,N-dimethylamino)phenoxy groups. From the UV-vis spectra measurements of 1a-c, 1-[3,5-bis(N,N-dimethylamino)phenoxy]-3-(2,4,6-tricyanophenylthio)Propane (1b) carrying the trimethylene chain as a spacer was found to have the strongest intramolecular charge-transfer interaction. A new methacrylate-type monomer carrying the 1b unit as a side chain, 1-(2,4,6-tricyanophenylthio)-3-[3,5-bis(N,N-dimethylamino)phenoxy]-2-propyl methacrylate (2), was prepared successfully in 9.2% total yield in seven steps. The monomer 2 homopolymerized in benzene, tetrahydrofuran, acetone, and dimethyl sulfoxide in the presence of 2,2′-azobis(isobutyronitrile) at 60°C to give polymers [poly(2)] with molecular weights of 6,000 to 98,000. An intramolecular charge-transfer interaction in the poly(2) was found to be larger than that in the monomer 2 and to increase with an increase in the degree of polymerization of the poly(2), suggesting that there is an existence of polymer effect other than the polymer effect due to the high local concentration of the donor-acceptor pair. © 1995 John Wiley & Sons, Inc.
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  • 10
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1511-1521 
    ISSN: 0887-624X
    Keywords: dispersion polymerization ; micron-size monodisperse polymer particles ; sty-rene ; butyl acrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of the nitrogen purge, monomer purification, type of agitation, and presence of costabilizer on the particle size distribution (PSD) was investigated in the dispersion po-lymerization of styrene in ethanol and in the dispersion copolymerization of styrene and butyl acrylate in a water-ethanol mixture. Purging with nitrogen and, to a lesser extent, monomer purification, were of paramount importance to achieve monodispersity. The type of agitation had a week effect on the PSD, whereas the presence of costabilizer had no effect on the PSD. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
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  • 11
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1581-1587 
    ISSN: 0887-624X
    Keywords: matrix polymerization ; polypyrrole ; chemical synthesis ; interpolymer complex ; water soluble polypyrrole ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidative matrix polymerization of pyrrole (Py) by Ce(IV) in the presence of Polyacrylic acid (PAA) has been studied to obtain water-soluble and insoluble products. The role of the PAA, Pyrrole, and Ce(IV) concentration, order of component addition, the structure of polymer matrix (PAA, Hydroxy Ethyl Cellulose (HES), Poly-N-vinylpyrrolidone (PVP)], and model unit of PAA (propionic acid), on the polymerization system were investigated.Interaction of PAA with insoluble polypyrrole (PPy) and the interpolymer complex formation were investigated along with the aggregation of PPy onto the matrix polymer followed by spectral shifts. FTIR results of insoluble products obtained from the PAA-Py-Ce(IV) system and solubility of the system is explained in light of the mechanism of the polymerization of pyrrole on the polymer matrix. © 1995 John Wiley & Sons, Inc.
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  • 12
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 415-426 
    ISSN: 0887-624X
    Keywords: thermotropic ; liquid crystalline polymer ; nematic ; synthesis ; characterization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of fully aromatic, thermotropic polyesters, derived from 3-phenyl-4,4′-biphenol (MPBP), nonlinear 4,4′-benzophenone dicarboxylic acid (4,4′-BDA), and various other comonomers was prepared by the melt polycondensation method and characterized for their thermotropic liquid crystalline behavior by a variety of experimental techniques. The homopolymer of MPBP with 4,4′-BDA had a fusion temperature (Tf) at 240°C, exhibited a nematic liquid crystalline phase, and had a narrow liquid crystalline range of 60°C. All of the copolyesters of MPBP with 4,4′-BDA and either 30 mol % 4-hydroxybenzoic acid (HBA), 6-hydroxy-2-naphthoic acid (HNA) or 50 mol % terephthalic acid (TA), 2,6-naphthale-nedicarboxylic acid (2,6-NDA) and low Tf values in the range of 210-230°C, exhibited a nematic phase, and had accessible isotropization transitions (Ti) in the range of 320-420°C, respectively. As expected, each of them had a broader range of liquid crystalline phase than the homopolymer. They had a “frozen” nematic, glassy order as determined with the wide-angle X-ray diffraction (WAXD) studies. The morphology of each of the “as-made” polyesters had a fibrous structure as determined with the scanning electron microscopy (SEM), which arises because of the liquid crystalline domains. Moreover, they had higher glass transition temperatures (Tg) in the range of 167-190°C than those of other liquid crystalline polyesters, and excellent thermal stabilities (Td) in the range of 500-533°C, respectively. © 1995 John Wiley & Sons, Inc.
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  • 13
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1727-1733 
    ISSN: 0887-624X
    Keywords: polymerizing detergents ; monomer micelles ; radical polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photo- and thermoinitiated radical polymerization of surface-active monomers with various structures was investigated in solution and in micelles in water. The relationship between kinetics and the structure of monomer associates was represented in the form of a universal curve. A model and kinetic description of polymerization in spherical micelles of monomer was proposed. The problem of micelle fixation by polymerization was solved. © 1995 John Wiley & Sons, Inc.
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  • 14
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1745-1749 
    ISSN: 0887-624X
    Keywords: viologen polymer ; lyotropic ; critical concentration ; synthesis ; characterization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [no Abstrat]
    Additional Material: 3 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1759-1765 
    ISSN: 0887-624X
    Keywords: compartmentalized ; seed ; emulsion ; oil-soluble initiators ; average radical number ; radical polymerization ; Kummer functions ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Expressions for calculating the stationary state distribution of radicals in compartmentalized systems with a constant number of reaction loci containing an oil-soluble initiator are given. Besides pairwise formation of radicals in the particles, desorption and reabsorption, water phase termination, solubility of the initiator in the aqueous phase, and the possibility of formation of a single radical species are taken into consideration. The calculation is based on a probabilistic analysis leading to a third-order recurrence relation solved using confluent, hypergeometric Kummer functions. Some calculated curves illustrating the de-pendence of the average number of radicals per particle on various relevant parameters are included. © 1995 John Wiley & Sons, Inc.
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  • 16
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1807-1816 
    ISSN: 0887-624X
    Keywords: Oxetane ; oxirane ; photoinitiated cationic polymerization ; semiempirical molecular orbital calculation ; real-time FT-IR ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoinitiated cationic polymerization of oxetane, oxirane (epoxide), and a formulation of both was carried out and their reactivity compared. To investigate a formulated system of oxetane and oxirane in photoinitiated cationic polymerization, computational and experimental methods were used. In the computational study, we employed a semiempirical molecular orbital method (AM1). On the other hand, the reactivities of each system were evaluated and compared experimentally by a real-time FT-IR method. The computational study reveals that oxetane seems to polymerize in SN2 mechanism, but two possibilities, of SN1 mechanism through the α-cleavage and of SN2 mechanism through β-cleavage, are implied for oxirane. Using the real-time FT-IR method, the formulation of oxetane and oxirane was proved to possess rather high reactivities of oxetane toward photoinitiated cationic polymerization. The formulated system exhibited slightly lower number-average molecular weight than oxetane but higher than oxirane. These experimental observations are well explained in terms of the calculated reaction paths. © 1995 John Wiley & Sons, Inc.
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  • 17
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1849-1857 
    ISSN: 0887-624X
    Keywords: emulsion polymerization ; acrylic polymers ; core shell ; supermicron ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The emulsion polymerization of large MMA/BA copolymer particles with narrow particle size distributions and core-shell structure is described. A series of sequential seeded growth emulsion polymerizations were used to obtain monodisperse particles with diameters of at least 3 μm, at 30% solids contents. Because the core and shell polymers used here were chemically similar, core-shell structures could not be verified by differential staining tech-niques. Core-shell structure was demonstrated by minimum film-forming temperature studies and by scanning electron microscopy in conjunction with energy dispersive x-ray analysis, using chlorine-labeled core polymers. © 1995 John Wiley & Sons, Inc.
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  • 18
    ISSN: 0887-624X
    Keywords: 2,4-ionene ; poly(quaternary ammonium)salt ; cobalt(II) phthalocyaninetetra-carboxylic acid ; cobalt(II) phthalocyanineoctacarboxylic acid ; mercaptoethanol ; autoxi-dation ; catalysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The promoting effects of 2,4-ionene on the cobalt(II) phthalocyaninetetracarboxylic acid-[CoPc(COOH)4] and cobalt(II) phthalocyanineoctacarboxylic acid-[CoPc(COOH)8] cata-lyzed autoxidation of 2-mercaptoethanol were studied. Dimerization of the CoPc(COOH)4 catalyst, combined with the disappearance of the catalytically inactive μ-peroxo complex and the appearance of substrate enrichment in the presence of 2,4-ionene, results in a 40-fold enhancement of the oxidation rate as compared with the polymer-free system. UV-VIS spectroscopy indicates that CoPc(COOH)8 is incapable of forming μ-peroxo complexes or 2,4-ionene-induced dimeric catalyst species under normal reaction conditions. Thus, it was possible to study exclusively the ionene-induced effect of substrate enrichment. Addition of 2,4-ionene to an aqueous CoPc(COOH)8 solution results in an activity enhancement by a factor of 2-3, which can be ascribed to substrate enrichment. Additionally, using mono-disperse ionene oligomers showed a molecular weight dependence of 2,4-ionene on the catalytic activity of CoPc(COOH)8, as was observed for the conventional 2,4-ionene/cobalt phthalocyaninetetrasodiumsulfonate system. The optimal polycation/catalyst ratios of both systems decrease with increasing chain length of 2,4-ionene, until a constant value is reached. This leads to the conclusion that the optimal polymer/catalyst ratios are predominantly determined by substrate enrichment. © 1995 John Wiley & Sons, Inc.
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  • 19
    Electronic Resource
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1873-1879 
    ISSN: 0887-624X
    Keywords: combined catalyst system ; polymerization ; polyphenylacetylene film ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The simultaneous polymerization and formation of polyphenylacetylene film by Nd(P204)3-Fe(AA)3-Al(i-Bu)3 catalyst system have been investigated. The combined catalytic effects between rare earth phosphonates with MT(naph)x or Fe(AA)3 systems are first proposed and compared. The polymerization features and kinetic behaviors with Nd(P204)3-Fe(AA)3-Al(i-Bu)3 system are described and discussed. The combined catalytic effects have the following order, respectively: Fe ≫ Co 〉 Cr 〉 Mn-Ni, Nd(P204)3-Nd(P507)3 〉 Nd(P350)3 and Tb 〉 Sm 〉 Yb 〉 Ho 〉 Lu 〉 Dy 〉 Nd-Er-Pr 〉 Y-Tm 〉 Ce 〉 Gd 〉 La. The overall polymerization activation energy was found to be 20.8 kJ/mol showing coordination-anionic polymerization characteristic. PPA films so obtained are very similar to the rare earth ones. © 1995 John Wiley & Sons, Inc.
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  • 20
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1907-1912 
    ISSN: 0887-624X
    Keywords: substituted polyacetylene ; fluorine-containing polymer ; transition-metal catalyst ; gas permeability ; pervaporation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis, properties, and membrane-separation functions of a novel fluorine-containing poly(phenylacetylene) were examined. The monomer used was [o-n-(perfluorohexyl)phe-nyl]acetylene, which has a rigid rod-like ortho-substituent. Polymers, whose intrinsic vis-cosities ([η]) were ca. 0.4-2.2 dL/g, were obtained in high yields with various W and Mo catalysts. The MoCl5-Ph3Sb catalyst achieved the highest [η] of 2.25 dL/g corresponding to an Mw over one million. The polymer was a brown solid soluble only in F -containing solvents such as m-(CF3)2C6H4. The oxygen permeability coefficient of the polymer mem-brane was 90 barrers, which is the second highest among those of ortho-substituted poly(phenylacetylenes). In the pervaporation of an ethanol-water mixture, the poly-mer membrane showed ethanol permselectivity [α(EtOH/H2O) = 1.7]. © 1995 John Wiley & Sons, Inc.
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  • 21
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1921-1925 
    ISSN: 0887-624X
    Keywords: telechelic polymers ; living polymerization ; cationic polymerization ; vinyl ether ; aldehyde ; water ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 22
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1979-1985 
    ISSN: 0887-624X
    Keywords: IPN ; zeolite ; polystyrene ; solid-state ; 13C-NMR ; SEM ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A hybrid inorganic/organic interpenetrating polymer network (IPN) of a three-dimensional network structure zeolite crystal (13X, powder) and crosslinked or linear polystyrene (PS) was prepared and characterized by differential scanning calorimetry (DSC), solid-state13C-NMR, and scanning electron microscopy (SEM). The size and shape of the crystalline zeolite particles were revealed on SEM micrographs in both the pure zeolite and the IPNs. Solubility tests and the results of DSC with solid-state 13C-NMR confirm that some organic PS chains are incorporated within the internal three-dimensional channels of the zeolite particles. We speculate that the internal PS chains may adopt an extended “one-dimensional” conformation and exhibit no bulk polymer glass transition. These novel hybrid inorganic/organic IPNs are a new kind of IPN structure. © 1995 John Wiley & Sons, Inc.
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  • 23
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1969-1978 
    ISSN: 0887-624X
    Keywords: poly(methyl methacrylate) ; TMPD ; two-photon ionization ; main chain scission ; ESR ; GPC ; radical anion ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The main chain scission reaction of poly(methyl methacrylate) (PMMA) doped with N,N,N,′,N′-tetramethyl-p-phenylenediamine (TMPD) was examined by ESR spectroscopy and GPC measurement, and the scission mechanism was analyzed. The two-photon ionization of TMPD with excimer laser excitation at 77 K produced an ester radical anion of PMMA (PMMA·m̌), which becomes the main chain tertiary radical —CH2—C·(CH3)—CH2—after the detachment of the ester side group by annealing of the sample at room temperature. The main chain scission radical ·C(CH3)(COOCH3)—(PMMA·) which was produced by the β-scission from—CH2—·C(CH3)—CH2—showed the 13-line ESR spectrum instead of the ordinary 9-line, due to the fast quenching of the sample to 77 K. The change of the molecular weight distribution was measured by GPC after several irradiation-and-annealing operations. The simulation of the GPC curve confirmed that the scission re-action occurs at random in the PMMA chain in the solid and the main chain scission yield from the ester radical anion, [PMMA·]/[PMMA·m̌], is 0.30. © 1995 John Wiley & Sons, Inc.
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  • 24
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2001-2011 
    ISSN: 0887-624X
    Keywords: surface modification ; aromatic polyamides ; oxygen plasma ; bond scission ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The surface of poly(p-phenylene terephthalamide) (PPTA) films was modified by oxygen plasma, and the modified film surface was analyzed by an advancing contact meter and X-ray photoelectron spectroscopy (XPS). The advancing contact measurement showed that the oxygen plasma treatment made the surface of the PPTA film hydrophilic. The XPS analyses also showed the increase in the O/C and N/C atom ratio, especially the O/C atom ratio, at the PPTA film surface by the oxygen plasma treatment. A main oxygen functionality formed by the oxygen plasma treatment is a carboxylic acid group, and a main nitrogen functionality formed is a protonated amino group. The formation of the oxygen and nitrogen functionalities formed by the oxygen plasma treatment is not restricted to the surface of the PPTA film, but penetrates at least 35 Å deep from the film surface. The formation of these carboxylic acid and protonated amino groups is a result of the bond scission of the amide linkages in the PPTA film. Interactions of photons in the oxygen plasma rather than interactions of electrons and activated oxygen atoms contribute greatly to the bond scission. © 1995 John Wiley & Sons, Inc.
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  • 25
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2013-2025 
    ISSN: 0887-624X
    Keywords: vacuum ultraviolet oxidation ; polyethylene ; polypropylene ; plasma-polymer interaction ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The emission from low-pressure microwave plasmas in the vacuum-ultraviolet (VUV) region (λ 〈 200 nm) was investigated in order to use these plasmas as light sources for the study of the VUV photochemistry of polyethylene (PE) and polypropylene (PP) as part of the study of plasma-polymer interaction. These polymers, immersed in low-presure oxygen, were exposed to radiation with wavelengths down to 112 nm, the cut off of magnesium fluoride used as a window to separate the polymer specimen from the plasma light source. Total oxygen incorporation in the surface [O], and the formation of hydroxyl, carbonyl, and carboxyl groups were measured using XPS in combination with chemical derivatizations, particularly their dependence upon the radiation spectrum and the oxygen pressure around the sample. In most experiments the surface oxygen concentration [O] attained a constant value that appears to be related to the initial oxidation rate; this suggests a competition between oxygen incorporation and chain scission reactions, followed by the removal of volatile oxidation products. PE is usually oxidized to a higher level than PP, the latter appearing to be more susceptible to reaction with atomic oxygen than PE. A general initiation mechanism for the VUV experiments is proposed that allows us to explain the observed differences in behavior between PE and PP, and the results obtained under different irradiation conditions. The nature of oxidation products is in both cases very similar to what is observed after direct plasma treatment of the polymers. We conclude that short wavelength radiation contributes very appreciably to the observed surface modification effects during plasma treatment of PE and PP. © 1995 John Wiley & Sons, Inc.
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  • 26
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2057-2067 
    ISSN: 0887-624X
    Keywords: methacrylate monomers ; polymerization kinetics ; stereostructure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of unsaturated monomers containing one or more hydroxyl groups by reaction between polyalcohols (number of OH, n≥2) and monoacid chlorides has been theoretically analyzed. The difficulties were shown involved in the preparation of these monomers with a high degree of purity even in the most favorable case of the completely substituted compound. The calculated mole fractions of the two monomers that can be obtained by reaction between neopentylglycol and methacryloyl chloride were compared with the experimental ones. Kinetic experiments of the polymerization of 3-hydroxyneopentyl methacrylate and 2-hydroxyethyl methacrylate were carried out at different temperatures in 1,4-dioxane for the former monomer and dioxane and absolute ethanol for the latter. Dilatometric techniques and nonlinear least-squares methods were used to obtain kinetic data and to determine the kinetic constants, respectively. In homogeneous solution the values of kp/k1/2t for the 3-hydroxyneopentyl methacrylate and 2-hydroxyethyl methacrylate was determined by 13C-NMR spectroscopy and the molar fractions of tactic triads and dyads were calculated from different resonance signals. The polymers are predominantly syndiotactic and follow a Bernoullian distribution of tactic sequences. Finally, the glass transition temperatures of both polymers, determined calorimetrically, were 145 and 89°C, respectively. © 1995 John Wiley & Sons, Inc.
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  • 27
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1917-1920 
    ISSN: 0887-624X
    Keywords: poly(amide-imide-sulfonamide)s ; unsymmetrical diamino monomers ; Yamazaki reaction ; triphenylphosphite ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 28
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1935-1940 
    ISSN: 0887-624X
    Keywords: solketal ; monocarbamate diol ; polyurethane ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 29
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1941-1942 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 30
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1957-1967 
    ISSN: 0887-624X
    Keywords: end-capping reactions ; oligo(styryl)lithium anions ; gas chromatography ; mass spectrometry ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Anionic living polymerization methods, using organometallic initiators such as butyllithium reagents, have proven useful for, inter alia, styrene polymerization and are amenable to subsequent functionalization of poly(styryl)lithium in the termination step. In this study, general methods for the selective preparation of small styrene oligomers and termination of the intermediate oligo(styryl)lithium anions were investigated. The crude reaction mixtures were analyzed directly by tandem gas chromatography/mass spectrometry (GC/MS). Of the carbon- and silicon-based electrophiles tested, chloro(chloroalkyl)silanes, Cl-SiR2(CH2)nCl in particular, were shown by GC/MS to be regioselective end-capping reagents, thus allowing subsequent transformation to the primary amine. The combined GC/MS data allow not only an estimate of the degree of functionalization, but also the identification of by-products, thus providing insight into the end-capping process that otherwise might be difficult to access. © 1995 John Wiley & Sons, Inc.
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  • 31
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1987-1994 
    ISSN: 0887-624X
    Keywords: aromatic polyamides ; polyisophthalalamides ; pendent oligomeric benzamide groups ; 5-(4-benzoylamino-1-benzoylamino)isophthalic acid ; water uptake ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of polyisophthalamides having pendent oligomeric benzamide groups were prepared by the Yamazaki reaction from common aromatic diamines and 5-(4-benzoylamino-1-benzoylamino)isophthalic acid. The latter was synthesized from 5-aminoisophthalic acid in a three-step synthesis by successive incorporation of benzamido groups. The new polymers were characterized by NMR, DSC, TGA, and WAXD and the properties were compared to those of corresponding unsubstituted polyisophthalamides. All of the polymers were essentially amorphous and their Tgs were about 20°C higher than the reference polymers. Initial thermal decomposition temperatures ranged from 375 to 420°C. All of the polymers were soluble in aprotic polar solvents without added salts. Properties of particular note were: the water uptake, which was particularly high, ranging from 7.5 to 18.2%, and the temporary insolubilization in concentrated sulfuric acid of films of the polymers heated for a short time to ≥ 200°C. © 1995 John Wiley & Sons, Inc.
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  • 32
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2049-2055 
    ISSN: 0887-624X
    Keywords: graft polymerization ; grafting rate ; electron beam irradiation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: LLDPE film pre-irradiated by electron beam (EB) in air and argon was grafted in an aqueous acrylamide solution containing Mohr's salt in the concentration range 0.0025-2% The grafting rate and yield were strongly dependent on the Mohr's salt concentration, mainly as a result of chain termination. The exponential grafting rate dependence on the pre-irradiation dose was quite insensitive to a hundred-fold variation in Mohr's salt concentration. © 1995 John Wiley & Sons, Inc.
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  • 33
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2157-2163 
    ISSN: 0887-624X
    Keywords: reactive polyester ; pendant carboxyl group ; chemoselective polycondensation ; polymer catalyst ; polymer reaction ; bifunctional catalytic mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatic polyester, copolyester, and poly(ester-amide-thioester) having pendant carboxyl groups are directly synthesized by the organic phase/water phase interfacial polyconden-sation using low-molecular and polymeric phase transfer catalysts. Spectral analysis of the resulting polymers indicates that the nucleophilicity of salts of phenols to diacid chloride is far higher than that of salts of carboxylic acids and chemoselective esterification occurs in a 100% yield. Even if the polymeric catalyst having amino acid moiety as a nucleophilic group is used in the polycondensation, the polymers do not contain anhydride groups. The polyester can be almost quantitatively converted to polymers with different reactive groups by reacting the pendant carboxyl groups with alkyl halides in a DMAc-H2O mixture con-taining K2CO3. A bifunctional catalytic mechanism is proposed for the chemical modification of the polyesters. © 1995 John Wiley & Sons, Inc.
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  • 34
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2175-2182 
    ISSN: 0887-624X
    Keywords: gadolinium tricarboxylate ; copolymerization of butadiene and styrene ; effect of pKa of ligand ; diad analysis ; cis polymerization mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homo- and copolymerizations of butadiene (BD) and styrene (St) were carried out by gadolinium catalysts having various tricarboxylate ligands [Gd(OCOR)3: R = CH3, CH2Cl, CHCl2, CCl3, and CF3], to investigate the effects of ligands and discuss the cis polymerization mechanism. Polymerization of BD with Gd(OCOR)3 - (i - Bu)3Al - Et2AlCl catalysts was carried out in hexane at 50°C. By each catalyst, poly(BD) having a high cis content (cis = 97-99%) in 22-85% yields for 2-24 h were obtained. The ligands with low pKa values increased the polymerization activity as follows: R of Gd(OCOR)3: CF3 〉 CCl3 〉 CHCl2 〉 CH2Cl ∼ CH3. On the other hand, in the polymerization of St or copolymerization of BD and St under similar conditions, the highest activity was attained by a Gd(OCOCCI3)3- based catalyst. The difference in the optimum ligand among the homo- and copolymerization of BD and St was discussed on the basis of energy levels of the catalysts. In the copolymers of BD and St, the cis-1,4 content of the BD unit decreased with increasing St content. Furthermore, according to the diad analysis of copolymers (St content ∼ 14.5 mol %) by 13C NMR spectroscopy, the low cis value of the BD unit was observed in the St-BD diad (cis/trans/vinyl = 24/53/23), while the high cis value of the BD unit remained in the BD-BD diad (cis/trans/vinyl = 89/10/1). These results suggest that the terminal BD unit is controlled by the cis configuration by the coordination between the penultimate cis vinylene unit and the gadolinium metal catalyst, whereas the presence of the penultimate St unit interferes with cis polymerization of the terminal BD unit. The difference in the coordination mechanism in the course of polymerization between rare earth metal and transition metal catalysts such as the Ni(acac)2 and Co(acac)3-based catalyst was also discussed. © 1995 John Wiley & Sons, Inc.
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  • 35
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2193-2201 
    ISSN: 0887-624X
    Keywords: ring-opening polymerization ; poly(trimethylene carbonate) ; butyltin tri-chloride ; cationic mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Numerous BuSnCl-3, Bu2SnCl-2, and Bu3SnCl-initiated polymerizations of cyclo(tri-methylene carbonate) (TMC) were conducted in bulk. In addition to the initiator, reaction time, temperature, and monomer/initiator (M/I) ratio were varied. Yields above 90% were obtained with all three initiators, but their reactivities decrease in the order BuSnCl3 〉 Bu2SnCl2 〉 Bu3SnCl. The maximum molecular weights decrease in the same order. With BuSnCl3 Mws up to 250,000 were obtained. These molecular weights were determined by GPC on the basis of the universal calibration method. In this connection Mark-Houwink equations for two solvents, tetrahydrofuran (THF) and CH2Cl2 were determined and compared with literature data. Furthermore, mechanistic aspects were studied. 1H- and 13C- NMR spectra revealed that BuSnCl3 forms complexes with the CO-group of TMC, whereas Bu2SnCl3 do not cause NMR spectroscopic effects. Kinetic studies in chloroform and nitrobenzene and a comparison with Bu3SnOMe suggest that at least BuSnCl3 initiates a cationic mechanism. However, in contrast to SnCl4 (or SnBr4), BuSnCl3 does not cause decarboxylation. Regardless of the initiator 1H-NMR spectroscopy revealed CH2OH and CH2CI endgroups in all cases. © 1995 John Wiley & Sons, Inc.
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  • 36
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2241-2250 
    ISSN: 0887-624X
    Keywords: poly(amide-imide)s ; trimellitic acid ; smectic-A phase ; phase transition ; synchrotron radiation ; bâttonet texture ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polycondensation of α, ω-bis(-4-aminophenoxy) alkanes with trimellitic anhydride chloride (TMA-Cl) in m-cresol yielded a new class of poly(amideimide)s. Starting from the same diamine spacers poly(amideimides) with a more regular sequence of amide and imide groups were prepared by another synthetic method. All these poly(amide-imide)s are semi-crystalline and melt in the range of 250-300°C. They form a smectic-A phase over a narrow temperature range and suffer thermal degradation at the isotropization temperature (330-350°C). The smectic-A phase was characterized by optical microscopy (“batonnet texture”) and by synchrotron radiation measurements conducted at a heating rate of 20°C. Furthermore, it is demonstrated that slight variation of the chemical structure, such as methyl substituents or meta positions in the spacer prevent the formation of a LC phase. © 1995 John Wiley & Sons, Inc.
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  • 37
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 621-627 
    ISSN: 0887-624X
    Keywords: phenolic-triazine ; cyanate ester ; phenol formaldehyde resin ; cardanol ; cyclotrimerization ; matrix resin ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cardanol incorporated-phenol-formaldehyde novolac resins were synthesized by acid and base catalyzed reactions. The novolacs were transformed to their cyanate esters. The thermal cure characteristics of the cyanate esters depended upon the composition. The presence of cardanol proportionately facilitated the curing. The thermal characterization of the novolacs and the corresponding cured phenolic-triazine networks indicated a dedicated a detremental effect of cardanol on the thermal stability and char residue of the resins. © 1995 John Wiley & Sons, Inc.
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  • 38
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 633-642 
    ISSN: 0887-624X
    Keywords: free radicals ; grafting ; kinetics ; methacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of grafting a basic monomer, 2-(dimethylamino)-ethyl methacrylate (DMAEMA) to hydrocarbon substrates have been investigated. These systems were chosen as models for the grafting of a homopolymerizable monomer to polyolefins such as polyethylene. The reactions with squalane and n-eicosane were initiated by an organic peroxide, 2,5-dimethyl 2,5 dit-butylperoxy)-3-hexyne; grafting yields become significant at high reaction temperatures and low monomer concentrations. In squalane, the order of reaction with respect to monomer increased from about 1.1 for 0.22-0.44M DMAEMA to almost 2 at 0.69M DMAEMA; the order with respect to initiator was 0.56. The overall activation energy in the 130-160°C temperature range was, however, surprisingly low, 42±5 kJ mol-1. When analytical data were used to separate the overall rate into those for grafting and homopolymerization, different kinetic paths were observed for the competing reactions. These results are interpreted in terms of two different mechanisms; intramolecular chain transfer plays an important role in grafting, while depropagation becomes a major factor in homopolymerization at temperatures above 150°C. © 1995 John Wiley & Sons, Inc.
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  • 39
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 653-663 
    ISSN: 0887-624X
    Keywords: photopolymerization ; poly(indanes) ; cationic polymerization ; photopolymerizable poly(imide)s ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a series of monomers containing isopropenylphenoxy groups was carried out. On irradiation with UV light in the presence of onium salt photoacid generators, these monomers undergo a chain extension reaction consisting of a dimerization followed by a Friedel-Crafts ring closure which results in the formation of polymers with indane groups in the backbone. Aryl imide-containing monomers bearing isopropenylphenoxy groups were also shown to undergo facile photoinduced cationic polymerization. The resulting polymers displayed excellent thermal stability. © 1995 John Wiley & Sons, Inc.
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  • 40
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2339-2345 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The state of p-phenylphenol molecules in dioxane/water mixture, a commonly used reaction system for enzymatic polymerization of phenols and aromatic amines, was investigated by difference UV absorption spectroscopy and Fourier transform (FT) Raman spectroscopy. The aggregate of p-phenylphenols is found on the basis of the exciton peaks observed in difference UV absorption spectra. FT Raman spectroscopy demonstrates further that p-phenylphenol molecules aggregate together in “face to face” fashion. A simplified model is proposed for aggregation of p-phenylphenol molecules in dioxane/water mixture, which can elucidate the variation of the molecular weight of poly (p-phenylphenol) coupled in the reaction system. © 1995 John Wiley & Sons, Inc.
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  • 41
    ISSN: 0887-624X
    Keywords: soluble ethynylene-containing polyamides ; palladium-catalyzed polyconden-sation ; ethynylene-bearing amide monomers ; thermal behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New ethynylene-containing aromatic polymides were synthesized by the carbon-carbon crosscoupling polycondensation of aromatic diiodides with aromatic amide-bearing diethynyl compounds in the presence of a palladium catalyst, cuprous iodide, and an organic base. The polymers having sulfone linkages were soluble in various organic solvents and their weight average molecular weights were in the range of 12,500 and 26,500. The polymers with the highest inherent viscosity were obtained, when the monomer ratio of a diethynyl compound to a diiodide was 1.01. The polymers showed no detectable glass transition temperature and no weight loss up to around 300° C in nitrogen. The thermal crosslinking of the polymers occurred at 280°C through the existing internal ethynylene group. © 1995 John Wiley & Sons, Inc.
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  • 42
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2393-2402 
    ISSN: 0887-624X
    Keywords: metallocene, supported ; polypropylene, isotatic ; propylene polymerization, kinetics of, modelling of ; polyolefins, particle growth model for ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several propylene polymerizations are carried out with supported metallocene catalyst, prepared by reaction of silica gel with methylaluminoxane and then with rac-dimethylsi-lanediylbis(indenyl)zirconiumdichloride. The rate-time curves obtained are analyzed to understand the influence of support and triisobutylaluminium on the reaction. As a first attempt to model this system we developed a partially new praticle growth model, based on a shell by shell fragmentation hypothesis (gradual break-up from the outside to the inside of the particle), and a final multigrain structure of the particle. A kinetic scheme including the TIBA interaction with the supported catalyst is also presented. The model prediction and the experimental data are compared for the rate-time curves and polymer properties. © 1995 John Wiley & Sons, Inc.
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  • 43
    ISSN: 0887-624X
    Keywords: 3-fluoro-4′-(11-vinyloxyalkoxy)-4-biphenyl (2R,3S)-2-fluoro-3-methylpen-tanoate ; “living” cationic polymerization ; liquid crystallinity ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and “living” cationic polymerization of 3-fluoro-4′-(11-vinyloxyundecany-loxy)-4-biphenylyl (2R,3S)-2-fluoro-3-methylpentanoate (12-11) and 3-fluoro-4′-(8-vi-nyloxyoctyloxy)-4-biphenylyl (2R,3S)-2-fluoro-3-methylpentanoate (12-8) are presented. Poly (12-11)s and poly (12-8)s with degrees of polymerization from 4.0 to 16.5 and poly-dispersities ≤ 1.13 have been synthesized and characterized by differential scanning cal-orimetry (DSC) and thermal optical polarized microscopy. Over the entire range of molecular weights poly (12-11)s and poly (12-8)s exhibit an enantiotropic SA and an unidentified SX phase. In addition, regardless of its molecular weight, poly (12-8) exhibits a S*c phase in between the SA and Sx phases. Poly (12-11) and poly (12-8) show lower transition tem-peratures and broader temperature ranges of all their mesophases as compared to the corresponding polymers without a fluorine atom on the biphenyl group. The role of the connecting group between the biphenyl and chiral group of the mesogenic unit on the phase behavior of these polymers is also discussed. Copolymers of 12-8 with (2R,3S)-2-fluoro-3-methylpentyl 4′-(11-vinyloxyundecanyloxy)biphenyl-4-carboxylate (13-11) {i.e., poly-[(12-8)-co-(13-11)] (X/Y), where X/Y represents the molar ratio of monomer 12-8 to monomer 13-11} with DP of ca. 11 and polydispersities lower than 1.23 were also syn-thesized and characterized. Their SA and S*c mesophases exhibit continuous dependences of composition and this support the assignment of the mesophases exhibited by poly (12-8). © 1995 John Wiley & Sons, Inc.
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  • 44
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2415-2423 
    ISSN: 0887-624X
    Keywords: photoinitiated cationic polymerization ; 1-propenyl ethers ; siloxanes ; 1-pro-penyl ether-functionalized siloxanes ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of 1-propenyl ether-functionalized siloxanes (PFS) has been achieved by the controlled, rhodium-catalyzed, chemoselective hydrosilation of 1-allyloxy-4(1-propen-oxy) butane with various H-functional siloxanes. It was shown that the hydrosilation pro-ceeds exclusively at the allyl ether group of 1-allyloxy-4(1-propenoxy) butane without par-ticipation at the 1-propenyl ether group. The photoinduced cationic polymerization of these monomers was studied using various analytical techniques and found to take place very rapidly. © 1995 John Wiley & Sons, Inc.
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  • 45
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2443-2447 
    ISSN: 0887-624X
    Keywords: polyaniline ; oxalic acid dopant ; EPR ; IR ; UV/V ; TGA ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyaniline-oxalic acid salts were prepared at 5 and 30°C by chemical polymerization of aniline using different concentration of oxalic acid. Polyaniline base was obtained from the corresponding polyaniline salt by dedoping using aqueous ammonium hydroxide solution. Conductivity measurements, elemental analysis, Infrared, electronic absorption, electron paramagnetic resonance spectral, and thermogravimetric analysis were performed on the polyaniline salts and bases. Composition and the extent of dopant in polyaniline salt systems where determined. The value of composition of polyaniline: oxalic acid is 4: 1.6 and the polymer yield is around 66%. The value of conductivity, polymer yield and composition of polyaniline-oxalic acid salt is independent of concentration of oxalic acid used and also the synthesis temperature. The results are compared with polyaniline-hydrochloride salt prepared by chemical polymerization. The conductivity of polyaniline-oxalic acid salt is three orders of magnitude lower than that of polyaniline-hydrocholoride salt. © 1995 John Wiley & Sons, Inc.
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  • 46
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2435-2441 
    ISSN: 0887-624X
    Keywords: poly(o-phenylenediamine) ; solubility ; conducting polymer ; molecular structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A conducting polymer, poly(o-phenylenediamine) (PoPD), has been obtained as stable film onto an electrode surface by the electropolymerization of o-phenylenediamine in 0.1 mol dm-3 H2SO4. The film thickness did not exceed 0.85 μm because of its low electrical con-ductivity. The virgin “doped” polymer film was soluble in dimethylsulfoxide N, N-dimeth-ylformamide, acetone, and tetrahydrofuran without any pretreatment. The highest solubility obtained was 17 g dm-3 in dimethylsufoxide. A cast film of PoPD on a substrate was prepared from its dimethylsulfoxide solution. The mean molecular weight of PoPD was found to be 11,000 with the gel permeation chromatography. The STM observation exhibited that the cast film was considerably uniform compared to the electrodeposited film. The cyclic voltammogram of such film showed a reversible redox property accompanied with excellent electrochromism between transparent yellow and brown. It was suggested from the 1H-FTNMR and FTIR spectra and the elemental analysis that the polymeric backbone has 1, 4-substituted benezenoid-quinoid structure. © 1995 John Wiley & Sons, Inc.
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  • 47
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2463-2471 
    ISSN: 0887-624X
    Keywords: cycloaliphatic epoxides ; mechanistic studies ; photoinitiated cationic poly-merization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a series of difunctional epoxides bearing two epoxycyclohexyl groups linked together by an alkylene ether group has been carried out. Subsequently, the reactivities of these novel monomers was investigated and compared to the reactivity of the cycloali-phatic epoxide, 3,4-epoxycyclohexylmethyl 3′,4′-epoxycyclohexane carboxylate (I) in pho-toinitiated cationic polymerization. It was observed that alkylene oxide linking the two epoxycyclohexyl groups was short and the monomers are more reactive than I. The effects of the photoinitiator structure and the experimental conditions of the cationic photopo-lymerization on the rates was also studied using real-time infrared spectroscopy. © 1995 John Wiley & Sons, Inc.
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  • 48
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2515-2519 
    ISSN: 0887-624X
    Keywords: thymine styrene monomer ; functional styrene monomer ; multifunctional monomer ; photoresist ; photocrosslinking ; photopolymer ; 2π + 2π photocyclization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 49
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2505-2513 
    ISSN: 0887-624X
    Keywords: neodymium ; polybutadiene ; alkylaluminum ; alkylaluminum chloride ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ternary neodymium-based catalyst for the polymerization of 1,3-butadiene, Nd(versatate)3/Ali-Bu2H/tert-butyl chloride, has been examined with respect to the effects of a range of alkylaluminums and alkylaluminum chlorides. Using either pre-formed or in situ catalysts, observations pertaining to catalyst activity and physical state and the characteristics of the final polymer are discussed. The catalyst activity series with the type of alkylaluminum was found to be: Aln-Pr3 ≫ Aln-Dodec3 = Aln-Oct3 = Aln-Hex3 〉 Ali-Bu2H 〉 Ali-Bu3 〉 AlEt3 ≫ AIMe3. Polybutadiene cis content was found to vary with the type of alkylaluminum used. Pre-formed catalysts using methylaluminum chlorides as chloride source were found to be the most active; AlMe2Cl chloride gave the highest activity. The activity of in situ catalysts prepared using alkylaluminum chlorides was found to be independent of alkylaluminum chloride structure. Polybutadiene prepared using catalysts based on different alkylaluminums and alkylaluminum chlorides was found to decrease in cis content with conversion. © 1995 John Wiley & Sons, Inc.
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  • 50
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2521-2522 
    ISSN: 0887-624X
    Keywords: gelatin ; sol-gel transition ; metal ions ; viscosity ; radiation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 51
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2533-2549 
    ISSN: 0887-624X
    Keywords: free radical ; grafting ; kinetics ; model ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Graft site initiation occurs by primary radical and/ or polymeric radical attack on the back-bone polymer. The controlling mechanism is determined by the structure of the backbone and the activity of the free radicals. The efficiency of incorporating monomer into the graft chains depends upon the graft site initiation mechanism and the mode of polymer chain termination (recombination or disproportionation). A kinetic analysis results a series of uniquely different expressions describing the graft efficiency, φ corresponding to different combinations of graft site initiation and chain termination mechanisms. The dependency of φ upon monomer, initiator, and backbone concentrations is different from case to case. The complete kinetic model is capable of predicting reaction rate, graft efficiency, graft frequency, graft ratio, and molecular weight averages and distributions. Simulations are provided to compare predicted results with experimental data for two different systems which show contrasting mechanisms of graft site initiation and mode of termination. © 1995 John Wiley & Sons, Inc.
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  • 52
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2613-2621 
    ISSN: 0887-624X
    Keywords: solution conformation ; amphoteric copolymer ; 14N-NMR ; 23 Na-NMR ; poly-electrolyte ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solution conformations and dynamic mobilities of novel amphoteric copolymers were studied for aqueous solutions of p(sodium 2-methacryloxyethanesulfonate-co-2-methacryloy-loxyethyltrimethylammonium iodide) [P(NaMES-co-METMAI)] as a function of com-position, concentration, and addition of HCI or KCI. As HCI or KCI was added successively to 5 w/v% copolymer solutions, the reduced viscosities of the solutions were reduced except the 1:1 copolymer solution. The dynamic mobility of the cationic side chain was estimated with the quadrupolar 14N-NMR relaxation technique. The motion of the interacting coun-terion, Na+, was studied by Poisson-Boltzmann electrostatic theories and the quadrupolar 23Na-NMR. Since the intramolecular 1:1 ion pair between MES- and METMA+ acts as an effective charge-screening factor, the copolymers P(NaMES-co-METMAI) behave as ordinary polyelectrolytes with the exception of the 1 : 1 copolymer. © 1995 John Wiley & Sons, Inc.
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  • 53
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2605-2612 
    ISSN: 0887-624X
    Keywords: complex formation ; PEO ; copolymer ; phenolic resin ; hydrogen bonding ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Comb copolymers formed from acrylamide and poly(ethylene-glycol) methacrylate macro-monomer (PAM-co-PEG) were compared to poly(ethylene oxide) (PEO) with respect to hydrogen bond complex formation with water-borne phenolic resins. The behaviors of the two types of high molecular weight polyethers were similar. Complex formation gave a transient increase in viscosity followed by precipitation. Copolymers with pendant PEG chain lengths ≥ 9 formed complexes with phenolic resin whereas PEG homopolymer with a molecular weight of 2000 did not form a complex. For both copolymer and high molecular weight PEO, the tendency of the complex to precipitate increased when the pH was decreased from 7 to 4. Acridine orange, a cationic dye, bound to the phenolic resin and, after the addition of PEO, yielded visible complex gels with diameters about 20 μm. © 1995 John Wiley & Sons, Inc.
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  • 54
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2657-2665 
    ISSN: 0887-624X
    Keywords: amphiphilic rubber ; butyl rubber ; saccharide ; microphase-separated structure ; thermoplastic elastomer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new type of amphiphilic elastomer was synthesized, which consisted of butyl rubber and a D-maltose derivative as a backbone and side groups, respectively. The synthesis was accomplished by the sequence of the three following reactions: (1) Hydroxyl groups of D-maltonolactone were protected by a trimethylsilyl group. (2) The resulting maltonolactone derivative was subjected to a reaction with chemically modified butyl rubber having pendant amino groups. (3) The protecting trimethylsilyl groups on the maltose residues were removed by treating with tetra-n-butylammonium fluoride. This new amphiphilic elastomer behaved as a thermoplastic elastomer and showed good mechanical properties. The saccharide seg-ments aggregated in the hydrophobic butyl rubber matrix to form a microphase-separated structure, as confirmed by differential scanning calorimetry, transmission electron mi-croscopy, small-angle x-ray scattering, and dynamic mechanical measurements. The ag-gregated saccharide domains are estimated to function both as crosslinking sites and rein-forcing fillers in the rubber matrix. © 1995 John Wiley & Sons, Inc.
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  • 55
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2673-2680 
    ISSN: 0887-624X
    Keywords: main chain LCPs ; ionic LCPs ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An ionogenic main chain liquid crystalline polymer was synthesized. In contrast to previous studies the charged sites were incorporated into the flexible spacer and not into the mesogenic group. This was done through quaternization of 1,2-bis(4-pyridylethane) with a biphenyl-4,4′-nonanoxytoluenesulphonate. The polymer displayed thermotropic and lyotropic me-sophases. The thermotropic mesophase was smectic. Organic counterions such as meth-ylsulfonates and p-toluenesulfonates were found to be favorable to the development of mesophases, due to the increased solubility and lower isotropisation temperatures, when compared to bromide counterion containing polymers. Easy supercooling, dependence on thermal history, and the development of batonnet textures on cooling from the melt were also observed. © 1995 John Wiley & Sons, Inc.
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  • 56
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2705-2714 
    ISSN: 0887-624X
    Keywords: coumarin derivatives ; photodimerization ; photocleavage ; reversible ; pho-tosensitizer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four photoreactive coumarin derivatives were successfully synthesized from 7-hydroxy-coumarin and 7-hydroxy-4-methylcoumarin, i.e., 7-propionyloxy-4-methylcoumarin (M1), 7-palmitoyloxy-4-methylcoumarin (M2), 7-propionyloxycoumarin (M3), and 7-palmitoy-loxycoumarin (M4). Reversible photodimerization (350 or 300 nm) and photocleavage (254 nm) of these coumarin derivatives dispersed in poly(vinyl acetate) (PVAc) were investigated by tracing their UV absorbance variations at 310 nm. The M2 and M4 with long palmitoyl chain show much better photoreaction reversibility than M1 and M3 with short propionyl chain. Moreover, photodimerization rate (under 350 nm) of M2 is greater than 200 times of that of M1. This has been explained by the formation of suitable conformation for revers-ible photodimerization due to the hydrophobic interactions. Photodimerization of M2 is ca. 3 times quicker than that of M4, indicating 4-methyl substitution enhances pho-todimerization. The influence of photodimerization wavelength (350 and 300 nm) and photosensitizer (benzophenone) have also been investigated in detail. © 1995 John Wiley & Sons. Inc.
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  • 57
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2741-2752 
    ISSN: 0887-624X
    Keywords: 3,3′-bis (4-flurobenzoyl) biphenyl ; poly (aryl ether ketone)s ; spectroscopic prop-erties ; thermal properties ; thermomechancial properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A monomer, 3,3′-bis (4-fluorobenzoyl) biphenyl, was prepared in high yield in two steps from inexpensive 3-chlorobenzoyl chloride and fluorobenzene, and polymerized by nucleophilic displacement reaction with various bisphenol monomers in tetramethylene sulfone to produce a series of high molecular weight poly(aryl ether ketone)s containing 3,3′-dibenzoylbiphenyl (DBBP) moieties. The spectroscopic, thermal, and thermomechanical properties of these polymers and related isomeric polymers having 2,2′-and 4,4′-DBBP units were determined and compared to study the effects of changes in the substitution pattern of the biphenyl unit. Except for the 2,2′-DBBP series of polymers, Tgs were found to increase with increasing linearity of the DBBP unit. The 2,2′-DBBP series of polymers had exceptionally high Tgs due to the sterically restricted motions in the biphenyl unit caused by the 2,2′-substitution. In addition, they also showed evidence for torsion with the 2,2′-DBBP unit, whereas in other isomeric polymers the DBBP units are believed to be relatively coplanar. Thermal stabilities and tensile moduli for these polymers proved to be independent of substitution patterns. © 1995 John Wiley & Sons, Inc.
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  • 58
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2787-2793 
    ISSN: 0887-624X
    Keywords: Ziegler-Natta catalysis ; EPDM synthesis ; metallocene catalyst ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4-Vinylcyclohexene (VCH) and cyclooctadiene (COD) were investigated as termonomers in EPDM (ethylene/propylene/diene) synthesis by using rac-ethylenebis (1-η5-indenyl) zir-conium dichloride (1) as a catalyst precursor. Homopolymerizations of VCH, vinylcycloh-exane and cyclohexene were compared. The parameter Kπκp, which is the apparent rate constant for Ziegler-Natta polymerization, is about the same for VCH and vinylcyclohexanebut is 10 times smaller for cyclohexene. Therefore, the linear olefinic double bond is more active than the cyclic internal double bond. VCH reduces ethylene polymerization rate but not propylene polymerization rate in copolymerizations. In terpolymerizations, VCH tends to suppress ethylene incorporation especially at elevated polymerization temperature and Lowers the polymer MW by about two-fold. COD has very low activity as a termonomer. © 1995 John Wiley & Sons, Inc.
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  • 59
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2865-2873 
    ISSN: 0887-624X
    Keywords: fumarate ; radical polymerization ; addition-abstraction mechanism ; ESR spectrum ; propagation rate constant ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radical polymerization behavior of ethyl ortho-formyl-phenyl fumarate (EFPF) using dimethyl 2,2′-azobisisobutyrate (MAIB) as initiator was studied in benzene kinetically and ESR spectroscopically. The polymerization rate (Rp) at 60°C was given by Rp = k[MAIB]0.76[EFPF]0.56. The number-average molecular weight of poly(EFPF) was in the range of 1600-2900. EFPF was also easily photopolymerized at room temperature without any photosensitizer probably because of the photosensitivity of the formyl group of monomer. Analysis of 1H- and 13C-NMR spectra of the resulting polymer revealed that the radical polymerization of EFPF proceeds in a complicated manner involving vinyl addition and intramolecular hydrogen-abstraction. The polymerization system was found to involve ESR-observable poly(EFPF) radicals under the actual polymerization conditions. ESR-determined rate constant (2.4-4.0 L/mol s) of propagation at 60°C increased with decreasing monomer concentration, which is mainly responsible for the observed low de-pendency of Rp on the EFPF concentration. Copolymerizations of EFPF with some vinyl monomers were also examined. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2841-2850 
    ISSN: 0887-624X
    Keywords: aromatic copolyesters ; poly(ethylene terephthalate) ; poly(ethylene naphtha-late) ; melt polycondensation ; physical properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolyesters containing rigid segments (naphthalene and terephthalene) and flexible seg-ments (aliphatic diol) structure were synthesized from DMN/DMT/EG (2,6-dimethyl naphthalate/1,4-dimethyl terephthalate/ethylene glycol) ternary monomers with various mole ratios. Copolyesters having intrinsic viscosities of 0.52-0.65 dL/g were obtained by melt polycondensation in the presence of metallic catalysts. The effect of reaction tem-perature and time on the formation of the copolyesters was investigated to obtain an op-timum condition for copolyester manufacturing. The optimum condition for PNT (poly-ethylene naphthalate terephthalate) copolyester manufacturing is the transesterification under nitrogen atmosphere for 4 h at a temperature of 185±2°C followed by polymerization under 2 mm Hg for 2 h at a temperature of 280°C. Most copolyesters have better solubilities than poly(ethylene naphthalate) (PEN) and poly(ethylene terephthalate) (PET) in various solvents. The effect of the starting mole ratio of DMN, DMT, and EG on the thermal properties of the resulted copolyesters was also investigated using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Glass transition temperatures of copolyesters were in the range of 70.7-115.2°C, and 10% weight loss in nitrogen were all above 426°C. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2893-2899 
    ISSN: 0887-624X
    Keywords: poly(p-phenylenebenzobisthiazole) ; poly(p-phenylenebenzobisoxazole) ; fiber ; molecular composite fiber ; benzocyclobutene ; compressive strength ; tensile strength ; tensile modulus ; phase separation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fibers consisting of a rigid rod polymer and thermoset resin matrices were prepared. Poly(benzo-[1,2-d : 5,4-d′]bisoxazole-2,6-diyl)-1,4-phenylene} (PBO) in polyphosphoric acid (PPA) was blended with isophthaloyl bis-4-benzocyclobutene (1) or 2,6-bis-4-benzocyclobutene benzo[1,2-d: 5,4-d′]bisoxazole (2), and fibers were spun from these dopes. As-spun fibers that did not show phase segregation between the two components as examined with an optical microscope, were soluble in methanesulfonic acid (MSA). After heat treat-ment, the fibers swelled but did not dissolve in MSA. A fiber cross section of heat-treated PBO-1 fiber showed well-dispersed benzocyclobutene polymer domains of 200-500 Å by transmission electron microscopy (TEM). Films cast from MSA solutions of PBO and 2 were homogeneous, and TEM of heat-treated fiber showed only one phase. A molecular composite fiber was made. Some of these fibers showed 20-30% improvement in compressive strength over unmodified PBO fiber. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2887-2892 
    ISSN: 0887-624X
    Keywords: plasma ; cascade arc ; surface modification ; fluorination ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The depth and possible mechanisms of the penetration of surface modification into porous media by a low temperature cascade are torch are investigated. Two different modes of such penetration (“flow controlled” and “diffusion controlled”) are evaluated. Three porous samples [stacks of 10 sheets of nonwoven fabrics of poly(ethylene terephthalate)each], placed at an axial distance of 24, 28, and 32 cm from the cascade are anode, are exposed to a low temperature cascade arc torch containing argon and CF4 or C2F4, and surface properties of each of the sheets within treated porous samples are examined by ESCA. It is shown that interaction of chemically reactive species, created in the low temperature cascade arc torch, with the surface is not limited to the surface directly contacted by the torch. The flow controlled penetration is more pronounced for the outer layers, while diffusion controlled penetration is within the inner layers of the porous structure. Substantial differences in the fluorination effect of CF4 (nonpolymer forming gas) and C2F4 (polymer forming gas) discharges for the second and third stacks are observed, that can be explained by the fact that the major effect of the CF4 cascade arc torch treatment is based on the reaction of reactive species with the surface polymer molecules. The effect of C2F4 cascade arc torch treatment is based on the reactions of reactive species with polymers as well as reactions of reactive species themselves at the surface (plasma polymerization). Reactivity of the species created in C2F4 discharge is much higher compared to that created in CF4 discharge, which is one of the major factors influencing penetration trends of low temperature cascade arc treatment into porous media. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 873-877 
    ISSN: 0887-624X
    Keywords: 4,4′-diamino-3′-nitrobenzanilide (DNB) ; poly-p-benzamide (PBA) ; poly-p-benzamide end-capped with nitro-p-phenylenediamine ; polyterephthalamide of 4,4′-diamino-3′-nitrobenzanilide ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 891-900 
    ISSN: 0887-624X
    Keywords: mercury-dithizone ; photochromic probes ; thermal relaxation rate ; free volume ; Tg ; thermal transition ; polystyrene ; poly(vinyl acetate) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mercury-dithizone complex both free and bonded to a polymeric system has been synthesized and used to measure the thermal transition of polystyrene, poly(vinyl acetate), and some other polymers. The thermal relaxation rate of the activated complex in dark has been found to be dependent on the free volume of a polymer matrix. The rate goes through a maximum above Tg of a polymer. A very sensitive method, based on thermal recovery of activated photochromic probe chromophore has been devised to measure the thermal transition of both single and multicomponent polymer matrices. © 1995 John Wiley & Sons, Inc.
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  • 65
    ISSN: 0887-624X
    Keywords: poly(ethylene oxide) ; (poly(oxy-1,2-ethanediyl) ; PEO ; hydrogen peroxide ; hydroxyl radicals ; hydroperoxyl radicals ; chain scission process ; oxidative degradation ; photodegradation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(ethylene oxide) (poly(oxy-1,2-ethanediyl) is rapidly oxidized by hydroxyl (HO•) and hydroperoxyl (HO•2) radicals generated by photolysis of hydrogen peroxide (H2O2) or by the catalytic decomposition of H2O2 by metallic silver. This process is accompanied by a chain scission during which the molecular weight decreases and the polydispersity changes. As a result of this process, the crystalline structure of poly(ethylene oxide) disappears, and the polymer becomes completely amorphous. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 979-987 
    ISSN: 0887-624X
    Keywords: Ziegler-Natta polymerization ; EPDM ; metallocene catalysts ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethylene (E), propylene (P), and 1,4-hexadiene (HD) were terpolymerized with rac-1,2-ethylenebis (1-η5-indenyl) zirconium(IV) dichloride and methylaluminoxane (Et[Ind]2ZrCl2/MAO), and compared with the copolymerizations of E/P, E/HD, P/HD, and terpolymerization using ethylidene norbornene (ENB) as the termonomer. HD lowers the polymerization activity, the effect is more pronounced for P/HD and E/P/HD using large amount of P, than for E/HD and E/P/HD using feed low in P. The polymer molecular weight is most strongly affected by the temperature of polymerization (Tp), whereas the E/P ratio in the feed has virtually no effect. The reactivity ratios rE and rP are 3.0 and 0.3, respectively, at 20°C but rP becomes larger than rE at TP = 70°C. 1H-NMR spectra showed occurrence of cycloaddition in the homopolymerization of HD; on the other hand, HD is incorporated in the terpolymer only by linear 1,2-addition. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1095-1105 
    ISSN: 0887-624X
    Keywords: 1,6-bis(4-aminophenoxy)naphthalene ; direct polycondensation ; polyamides ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new bis(phenoxy)naphthalene-containing diamine, 1,6-bis(4-aminophenoxy)naphthalene, was synthesized in two steps from the condensation of 1,6-dihydroxynaphthalene with p-chloronitrobenzene in the presence of potassium carbonate, giving 1,6-bis(4-nitrophenoxv)naphthalene, followed by hydrazine hydrate/Pd - C reduction. A series of polyamides were synthesized by the direct polycondensation of the diamine with various aromatic dicarboxylic acids in the N-methyl-2-pyrrolidone (NMP) solution containing dissolved metal salts such as CaCl2 or LiBr using triphenyl phosphite and pyridine as condensing agents. The polymers were obtained in quantitative yield with inherent viscosities of 0.78-3.72 dL/g. Most of the polymers were soluble in aprotic solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), NMP, and they could be solution-cast into transparent, flexible and tough films. The casting films had tensile strength of 102-175 MPa, elongation at break of 8-42%, and tensile modulus of 2.4-3.8 GPa. The polymers derived from rigid dicarboxylic acids such as terephthalic acid and 4,4′-biphenyldicarboxylic acid exhibited some crystalline characteristics. The glass transition temperatures of the polyamides were in the range of 238-337°C, and their 10% weight loss temperatures were above 487°C in nitrogen and above 438°C in air. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1119-1124 
    ISSN: 0887-624X
    Keywords: poly(vinyl alcohol) ; silylation ; hexamethyldisilazane ; liquid ammonia ; kinetics ; properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Silylation of poly(vinyl alcohol) has been performed with hexamethyldisilazane in liquid ammonia in an autoclave. This novel procedure has the advantage that the educt, the reagent, and the product are soluble in ammonia, which works under homogeneous conditions. No salt like by-products are formed and no tedious purification of the product is necessary. The degree of silylation has been adjusted through the ratio of silylating agent to hydroxy groups. Random incorporation of trimethylsilyl groups was proven by the linear dependence of the glass transition temperature from the degree of silylation and the solubility of the partially silylated material. Quantitative investigation of the silylation reaction showed first-order kinetics for the initial and final stages of the reaction indicative of a reaction where k1 〉 k2 〉 k3. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1107-1118 
    ISSN: 0887-624X
    Keywords: polystyrene ; glycidyl methacrylate ; methyl methacrylate ; epoxy ; emulsion polymerization ; seeded growth ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Colloidal polystyrene particles with surface epoxy groups have been synthesized through surfactant-free emulsion copolymerization of styrene with glycidyl methacrylate; and through copolymerization of glycidyl methacrylate (GMA) and methyl methacrylate as shells around existing polystyrene seed particles. We developed two titration methods to quantify the number of epoxy groups that survived the polymerization processes. The styrene-GMA copolymer particles were judged to be unsatisfactory as model colloidal materials due to their size polydispersity and unknown internal distribution of epoxy groups. The core-shell particles had high epoxy surface densities with at least 60% of the initial epoxy groups surviving the synthesis process. Transmission electron microscopy shows that the thickness of the epoxy-rich shell is less than expected based on the volume of monomers added, suggesting that some of the monomer forms water-soluble oligomers. Photon correlation spectroscopy measurements imply that the shell is swollen with water and consists of polymer configurations which extend out into solution. The morphological details vary consistently with the GMA content, and hence the hydrophilicity, of the shell polymer. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1133-1142 
    ISSN: 0887-624X
    Keywords: Diels-Alder polyaddition ; coronand structure ; bispyrones ; bismaleimides ; polyimides ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of various substituted bis(2-pyrone)s with bismaleimides in dilute solution was carried out to produce linear soluble polymers with coronand structure. The number-average molecular weights of the polymers ranged from 7000 to 18,000 (vapor pressure osmometry). Polymer structures were identified by NMR spectroscopy and model reactions. The stereochemistry and the mechanism are discussed. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1125-1132 
    ISSN: 0887-624X
    Keywords: butadiene ; polymerization ; neodymium ; molecular weight ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The homopolymerization of 1,3-butadiene in a stirred batch reactor with the catalytic system Nd octoate/diethyl-aluminium chloride/triisobutyl-aluminium in n-heptane was studied. The effect of various reaction conditions on especially high conversion and molecular weight is reported. Polymerization is shown to be first order with respect to both monomer and neodymium. Molecular weights are high and broadly distributed. Chain transfer to triisobutylaluminium is the main factor governing molecular weight development. A mechanism of polymerization is presented with the chain transfer process incorporated. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1143-1151 
    ISSN: 0887-624X
    Keywords: poly(aryl ether ketone)s ; amorphous ; thermally stable ; fluorinated polymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two novel fluorinated monomers were prepared and polymerized with biphenols to produce amorphous, thermally stable poly(aryl ether ketone)s. The properties of the fluorinated polymers are compared to those of unfluorinated, amorphous poly(aryl ether ketone)s. The presence of fluorine in the polymers was found to cause a decrease in glass transition temperature and Young's moduli, however, no increase in thermal stability was observed. The fluorinated polymers are soluble in common organic solvents such as chloroform and methylene chloride at room temperature, and also show solubility in solvents containing a ketonic moiety, such as acetone. Evidence of polymer branching through fluorines considered to be unreactive under the polymerization conditions was found. Efforts were made to evaluate the reactivity of fluorine atoms under the polymerization conditions using both molecular modeling and 19F-NMR to ascertain if such branching could be avoided. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2493-2504 
    ISSN: 0887-624X
    Keywords: alkoxyallene monomers ; cationic photopolymerization ; isomerization of propargyl ethers ; diaryliodonium salts ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of cationically polymerizable mono-and difunctional alkoxyallene monomers have been prepared via the straight forward base catalyzed isomerization of the corresponding propargyl ethers. Rate studies conducted using real-time infrared spectroscopy showed that these monomers exhibit high reactivity in photoinitiated cationic polymerization. Monomers bearing a single alkoxyallene group undergo rapid polymerization to yield crosslinked polymers indicating that both double bonds react during polymerization. A mechanism has been proposed that explains this observation. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2753-2758 
    ISSN: 0887-624X
    Keywords: Poly(ethylene terephthalate) graft copolymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction between poly(ethylene terephthalate) and four vinyl monomers, methacrylic acid, methyl methacrylate, styrene, and vinyl acetate, has been studied using hydrogen peroxide, benzoyl peroxide, azobisisobutyronitrile, and cobalt acetylacetonate as initiators. The ease of addition of the monomer to the polymer follows the solubility of the monomer in the polymer film. No chemical interaction occurs between the PET film and the monomer; rather, the monomer is homopolymerized within the film and forms a semi-interpenetrating network so that the two homopolymers cannot be separated unless the PET matrix is destroyed. © 1995 John Wiley & Sons, Inc.
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  • 75
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2795-2801 
    ISSN: 0887-624X
    Keywords: Ziegler-Natta catalysis ; EPDM synthesis ; metallocene catalyst ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethylenebis (η5-fluorenyl) zirconium dichloride (1) and rac-dimethylsilylene bis (1-η5-in-denyl) zirconium dichloride (2) were activated with methylaluminoxane (MAO) to catalyze ethylene (E) propylene (P) copolymerizations. The former produces high MW copolymer at 20°C rich in ethylene with reactivity ratio values of rE = 1.7 and rP 〈0.01, whereas the latter produces lower MW random copolymers with rE = 1.32 and rp = 0.36. Ethylidene norbornene (ENB) complexes with 1/MAO but does not undergo insertion in the presence of E and P. In contrast, 2/MAO catalyzes terpolymerization incorporating 9-15 mol % of ENB with slightly lower MW and activity than the corresponding copolymerizations. In comparison, 1,4-hexadiene was incorporated by 2/MAO with much lower A and MW. Terpolymerizations were also conducted with vinylcyclohexene using both catalyst systems. The steric and electronic effects in these processes were discussed. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2833-2840 
    ISSN: 0887-624X
    Keywords: polyamides ; diamantane ; high-temperature solution polycondensation ; in-terfacial polycondensation ; characterization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,6-Diamantane dicarboxvlic acyl chloride (I) was used as a monomer with various aromatic diamines to synthesize polyamides by interfacial polycondensation and solution polycon-densation. The polyamides prepared by interfacial polycondensation had inherent viscosities between 0.38 and 0.15 dL/g. The polyamides prepared by solution polycondensation had inherent viscosities between 0.62 and 0.25 dL/g. The polyamides IIIa prepared by solution polycondensation showed the main melting transition at 380°C by dynamic mechanical analysis. In addition, it was quite temperature-stable and maintained good mechanical properties (G′⋐108 Pa) up to high temperatures close to the main transition well above 350°C. The polyamide IIIA had a tensile strength of 35 MPa, elongations to break of 10%, and initial modulus of 0.8 GPa. Some of the polyamides were soluble in NMP, DMAc, and DMSO, depending on soft segment moiety of diamine (II). The polyamides prepared by interfacial polycondensation have a greater tendency to form crystal than those prepared by solution polycondensation, as evidenced by x-ray diffraction studies. These polyamides had glass transition temperatures in the 270-300°C range, and 5% weight loss temperatures up to 435°C in nitrogen. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2917-2924 
    ISSN: 0887-624X
    Keywords: liquid-crystalline copolymer ; chiral nematic phase ; smectic phase ; chiral spacer ; carbazolyl group ; electron donor-acceptor interaction ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Side-chain liquid crystalline polymers containing both mesogenic (carbazolylmethylene)aniline and (4′-nitrobenzylidene)aniline units with various spacer groups were prepared to examine effects of the structure of spacer groups on the liquid crystalline properties. The copolymer containing (R)-(+)-2-methylpropylene as a chiral group in the spacer unit induced a smectic phase; the copolymer with a trimethylene spacer of similar length to the chiral spacer exhibited a nematic phase. Smectic phases were observed for the copolymer containing the chiral spacer group when the proportion of the carbazolyl group was in the range of 0.55-0.88. For example, the copolymer with the proportion of the carbazolyl group of 0.68 expressed the smectic phase from 88° to 167°C. This isotropic temperature was 37° higher than the calculated value (130°C) based on an assumed copolymer composition without the electron donor-acceptor interaction. Thus, it is assumed that for the chiral copolymer containing both electron donor and acceptor groups, the thermal stability and the induction of the smectic phase were caused by both the electron donor-acceptor interaction and the existence of the chiral group in the spacer unit. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2951-2959 
    ISSN: 0887-624X
    Keywords: poly(vinyl chloride) latexes ; miniemulsions ; stable monomer droplets ; mono-disperse vinyl chloride emulsions ; secondary particle formation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(vinyl chloride) latexes have been prepared by polymerization in micron and submicron sized monomer droplets. Monomer emulsions with excellent long time stability were obtained by diffusional swelling of vinyl chloride monomer into preformed, stable polydisperse pre-emulsions of water-insoluble oils or monodisperse, oligomer styrene seed particles. It was found that the size and size distribution of the final latex particles were determined by those of the parent monomer emulsions. Except for the secondary particles formed during polymerization, the size and size distributions of the latex particles were found to be com-parable to those of the monomer emulsions employed, indicating a complete nucleation of the parent emulsion droplets. The extent of secondary particle formation was found to be very dependent upon the emulsifier concentration as well as on the type and amount of initiator used. © 1995 John Wiley & Sons, Inc.
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  • 79
    ISSN: 0887-624X
    Keywords: thermally stable polymers ; sucrose-based comonomers and the additive ; octa-O-allylsucrose ; octa-O-crotylsucrose ; penta-O-methylsucrose trimethacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of methyl methacrylate polymers have been prepared containing sucrose-based crosslinkers and additives. Thermogravimetry and long-term aging studies at 200°C show that sucrose-based alkyl and allyl ethers provide unprecedented thermal stability to linear, as well as crosslinked, poly (methyl methacrylate) or PMMA. Linear PMMA and PMMA crosslinked with trimethylolpropane trimethacrylate (TMPTMA) both degrade at 284°C. PMMA containing octa-O-crotylsucrose (1 mol %) degraded at 322°C. Depending on concentration, PMMA containing octa-O-allylsucrose (0.1-1.0 mol % and higher) degraded between 334 and 354°C, and PMMA containing 1′,6,6′-trimethacryloyl-2,3,3′,4,4′-penta-O-methylsucrose (0.1-1.0 mol %) degraded between 309 and 320°C. PMMA containing (1 mol % each) sucrose-based esters, ester-ether derivatives, all degraded at or below the degradation temperature of pure PMMA. Long-term air aging studies revealed that PMMA containing penta-O-methylsucrose trimethacrylate, octa-O-allylsucrose, and octa-O-crotylsucrose did not flow or sag after heating for 24 h at 200°C, but the polymers did show yellowing. While linear and crosslinked samples of PMMA containing compounds other than sucrose ethers lost more than 50% of their original weight within 15 h at 200°C, PMMA containing sucrose-based ethers lost about 8 and 20% of their original weight after 1 and 8.5 days, respectively. Herein we propose a unique mechanism by which saccharide ethers may be imparting this unprecedented thermal stabilization to PMMA. While tertiary hydrogens alpha to oxygens in saccharide ethers are stable to chain transfer during normal polymerization temperatures, they readily chain transfer at 200°C where PMMA is unstable. Chain transfer of these hydrogens is followed by fragmentation to produce alkyl, allyl or crotyl radicals, which combine with the macroradicals and terminate depropagation. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 63-69 
    ISSN: 0887-624X
    Keywords: sodium polymethacrylate ; sodium nuclear magnetic resonance ; paramagnetic shielding ; temperature dependence ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The information for the interaction between water molecules and a polyelectrolyte was obtained from 23Na-NMR studies for sodium polymethacrylate in water-methanol mixtures. The chemical shift and the line width of the 23Na nucleus give the information on the immediate magnetic environment and the motion of the nucleus, respectively. The change of the chemical shift for 23Na nucleus is investigated by decreasing the temperature and changing the mol fraction of water in the solvent. According to these results, the hydrogen bonding of water molecules and polyanions becomes weaker as the temperature of the system decreases, but the interaction increases when the temperature is below the freezing point for water in this system. This effect, due to the change of temperature, becomes higher as the water mol fraction increases in the solvent. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 55-62 
    ISSN: 0887-624X
    Keywords: 29Si-NMR ; IR ; poly(phenylsilsesquioxane) ; copolymer ; hydrolyzate ; prepolymer ; molecular structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular structure of the hydrolyzate, and of the prepolymers and polymerization products of phenyltrichlorosilane and diphenyldichlorosilane are investigated. 29Si-NMR measurements reveal the kinds of component units and their ratio in each synthesis step. The molecular structure of the prepolymer chain end and the polymerization product are also discussed in relation to the change in the NMR spectra. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 79-83 
    ISSN: 0887-624X
    Keywords: monomer-isomerization ; copolymerization ; styrene ; butenes ; Ziegler-Natta catalysts ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomer-isomerization copolymerizations of styrene (St) and cis-2-butene (c2B) with TiCl3-(C2H5)3Al catalyst were studied. St and c2B were found to undergo a new type of monomer-isomerization copolymerization, i.e., only isomerization of 2B to 1-butene (1B) took place to give a copolymer consisting of St and 1B units. The apparent copolymerization parameters were determined to be rst = 16.0 and rc2b = 0.003. The parameters were changed by the addition of NiCl2 (rSt = 8.4, rc2b = 0.05). The copolymers containing the major amount of St units were produced easily through monomer-isomerization copolymerization of St and 2B. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 85-88 
    ISSN: 0887-624X
    Keywords: poly(γ-glutamic acid) ; esterification ; thermal properties ; biopolymer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The esterification of poly(γ-glutamic acid) (γ-PGA) produced by Bacillus subtilis F2-01 with alkyl halides was carried out at 60°C in N-methyl-2-pyrrolidinone (NMP) in the presence of sodium bicarbonate to obtain the corresponding esterified γ-PGA. The thermal properties of these γ-PGA esters were examined by differential scanning calorimetry and thermogravimetry. γ-PGA esters were more stable than free acid type γ-PGA, which decomposed at 210°C. Melting temperature (Tm) of γ-PGA esters could be observed at 230-250°C. Tm of γ-PGA n-alkyl esters reached a maximum at an alkyl chain length of n = 3. © 1995 John Wiley & Sons, Inc.
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  • 84
    ISSN: 0887-624X
    Keywords: cross-conjugated polymer ; crossed-aldol condensation ; cyclic ketone ; polyketone ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Insoluble cross-conjugated polyketones were prepared from terephthalaldehyde and a variety of cycloaliphatic ketones by the crossed-aldol condensation. Elemental analyses and infrared spectra suggest that the polymeric aldol intermediates were not completely dehydrated. Evidence is also presented that suggests conjugate addition of the base to the α,β-unsaturated ketone may occur. Soluble cross-conjugated polyketones were prepared from terephthalaldehyde and 2-indanone, which contains no beta hydrogens, and from cycloaliphatic ketones and 1,2-bis(4-formylphenoxy)ethane, a dialdehyde containing isolated aldehyde groups. It is proposed, therefore, that the lack of solubility in the terephthalaldehyde-based polyketones arises from crosslinking via enolate anions formed at the beta position of the cyclic ketones, which are delocalized through the carbonyl groups of neighboring backbone repeating units. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 109-116 
    ISSN: 0887-624X
    Keywords: reactivity ratios ; microstructure ; 13C-NMR ; vinyl acetate ; alkyl acrylate copolymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Vinyl acetate)/(ethyl acrylate) (V/E) and (vinyl acetate)/(butyl acrylate) (V/B) copolymers were prepared by free radical solution polymerization. 1H-NMR spectra of copolymers were used for calculation of copolymer composition. The copolymer composition data were used for determining reactivity ratios for the copolymerization of vinyl acetate with ethyl acrylate and butyl acrylate by Kelen-Tudos (KT) and nonlinear Error in Variables methods (EVM). The reactivity ratios obtained are rv = 0.03 ± 0.03, rE = 4.68 ± 1.70 (KT method); rv = 0.03 ± 0.01, rE = 4.60 ± 0.65 (EV method) for (V/E) copolymers and rv - 0.03 ± 0.01, rB - 6.67 ± 2.17 (KT method); rv = 0.03 ± 0.01, rB = 7.43 ± 0.71 (EV method) for (V/B) copolymers. Microstructure was obtained in terms of the distribution of V- and E-centered triads and V- and B-centered triads for (V/E) and (V/B) copolymers respectively. Homonuclear 1H 2D-COSY NMR spectra were also recorded to ascertain the existence of coupling between protons in (V/E) as well as (V/B) copolymers. © 1995 John Wiley & Sons, Inc.
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 97-107 
    ISSN: 0887-624X
    Keywords: transesterification ; interfaces ; diffusion ; mixing ; solvent effect ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article presents a unique example dealing with how chemical reactions between immiscible polymers in the melt behave differently than they would do in solution. Specifically, a model reaction was chosen: the transesterification between poly(ethylene-co-methyl acrylate) (EMA) and polystyrene mono-hydroxylated at the chain end (PSOH). It was carried out in the melt in a batch mixer. The overall rate of this reaction has a similar dependence of temperature, composition of reactants, and the nature and concentration of catalyst as in solution. The reactivity of PSOH decreases drastically with increasing molecular weight, and it becomes very weak when the molecular weight exceeds 8000 g/mol. As opposed to a reaction in solution or in a homogeneous melt, mechanical mixing increases the reaction rate since it generates interfacial area and reduces the diffusion length. The EMA-g-PS graft copolymer formed at the interfaces reduces the interfacial tension, and increases the miscibility of the reaction mixture. However, its occupation of the interfaces reduces contact between the reactive moieties, thus decreasing the overall reactivity. More importantly and much to our surprise, adding 1 to 2 wt % of an inert solvent increased greatly the overall reaction rate. While an increased interfacial mixing and diffusion by the presence of minor amounts of solvent are thought to be the major factors contributing to the drastic increase in reactivity, numerous questions still remain. Nevertheless, this study clearly showed that as opposed to a reaction in solution, mechanical mixing and the presence of minor amounts of solvent are two additional and critical means to control chemical reactions between immiscible polymer melts. © 1995 John Wiley & Sons, Inc.
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  • 87
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 117-124 
    ISSN: 0887-624X
    Keywords: substituted polyacetylene ; silicon-containing polymer ; silylmethyl group ; transition-metal catalyst ; living polymerization ; gas permeability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel phenylacetylene (PA) monomers, which have o-silylmethyl groups of different bulkinesses, i.e., o-Me3SiCH2PA, o-Et3SiCH2PA, and o-t-BuMe2Si-CH2PA, polymerized with W and Mo catalysts in high yields. The MoCl5-Ph4Sn catalyst achieved the highest weight-average molecular weights (Mw 7 × 105 - 12 × 105), and the Mw increased as the ortho-substitutent became bulkier (e.g., Mw of o-t-BuMe2SiCH2PA: 12 × 105). These monomers polymerized in a living fashion by the MoOCl4-n-Bu4Sn-EtOH catalyst. The resulting polymers were soluble in common solvents such as toluene and chloroform. In the UV-visible spectra, a tendency was observed that absorption maxima shifted to longer wavelengths as the substituents became bulkier. Membranes of the polymers were fairly permeable to gases (e.g., oxygen permeability coefficients 30-80 barrers). Though o-(Me3Si)2CHPA also polymerized with W and Mo catalysts, the product polymer was partly insoluble in any solvent. © 1995 John Wiley & Sons, Inc.
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  • 88
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 125-135 
    ISSN: 0887-624X
    Keywords: isospecific polymerization ; stereocontrol energy ; agostic interaction ; steric insertion probability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereocontrol energy (ΔE0) is investigated as a measure of enantioselectivity of ansa-zircoocenium catalyst in propylene polymerization; it was calculated with MM2 (molecular mechanics) force field using π complex (°C) and transition state (TS) geometries obtained by ab initio molecular orbital methods. Both rac-ethylenebis (1-η5-indenyl) - (1) and rac-ethylenebis (1-η5-4,5,7,8-tetrahydroindenyl) (2) zirconocenium species are isospecific in either the π-complexes or the transition states. The stereoselectivity is greater if there is α-agostic interaction; it is lowered in the cases of β and γ agostic interactions. The 13C-NMR steric pentad distribution indicates the poly(propylene) to be much less stereoregular than that predicted by ΔE0. Following the occurrence of a regiochemical insertion error, the addition of another monomer via any mode is prohibitively unfavorable. The catalyst suffers loss of stereospecificity as temperature of polymerization increases. Insertion via transition states involving different agostic interactions could be one explanation for the observed loss. © 1995 John Wiley & Sons, Inc.
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  • 89
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 89-95 
    ISSN: 0887-624X
    Keywords: enzyme-catalyzed polymerization ; polyester preparation ; poly(1,4-butanediol glutarate) ; pig pancreas lipase ; dimethoxybenzene solvents for enzymatic polymerization ; in vacuo leaving group removal ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enzyme-catalyzed preparation of polymers offers several potentially valuable advantages over the usual polymerization procedures and has been studied for several years. A significant limitation on the polyesters prepared to date has been the low molecular weights achieved. The present studies have established that, in the polycondensation of bis(2,2,2-trifluoroethyl) glutarate with 1,4-butanediol using porcine pancreatic lipase as the catalyst, this limitation arises from at least two sources: hydrolysis of activated ester end groups by water introduced along with the enzyme and the polymerization's reaching equilibrium despite using the poorly nucleophilic 2,2,2-trifluoroethanol as the leaving group. Evidence is also developed that the presence of trifluoroethanol accelerates the release of the enzyme-bound water which hydrolyzes the activated ester end groups. The hydrolysis could be avoided by choosing a relatively high-boiling solvent, such as bis(2-ethoxyethyl) ether, then removing the trifluoroethanol by placing the reaction mixture under vacuum periodically or by drying the enzyme rigorously. The vacuum method also removed the limitation on molecular weight resulting from the reaction's reaching equilibrium. A further improvement in the molecular weight to nearly 40,000 daltons, well within the range that is technically interesting, was achieved by using 1,2-dimethoxybenzene or 1,3-dimethoxybenzene as the polymerization solvent. © 1995 John Wiley & Sons, Inc.
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  • 90
    ISSN: 0887-624X
    Keywords: amphiphilic copolymer ; fluorescence ; excimer ; photolysis ; steric hindrance ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amphiphilic copolymers containing 1-(2-naphthyl)ethyl ester groups were prepared and their fluorescence properties were examined. The fluorescnce spectra of the copolymers with a higher naphthyl content showed predominantly a broad monomer emission with λmax at 340 nm in methanol, whereas a structured emission with λmax at 344 and 362 nm was observed in aqueous solution. The former spectra changed rapidly to the latter ones upon UV irradiation. Photolysis of the copolymers and the monomeric model compound in methanol gave 2-vinylnaphthalene, whose fluorescence agreed with those of copolymers in water, together with methyl ether, alkylnaphthalenes, and other products. These results indicate that the copolymers hold vinylnaphthalene-like traps, which may emit preferentially in water because of efficient sensitization. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 91
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 159-164 
    ISSN: 0887-624X
    Keywords: poly(p-phenylenebenzobisoxazole) ; polyphenylene sulfide ; pendent group ; crosslinking ; heat treatment ; compressive strength ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(p-phenylenebenzobisoxazole) (PBO) fiber with polyphenylene sulfide (PPS) pendent groups was made to improve PBO fiber compressive strength by crosslinking. PPS moieties allowed the polymeric network to crosslink at heat-treatment temperatures at which PBO does not thermally degrade. PBO-PPS fiber heat-treated for 30 s at 600°C did not dissolve or break up in methanesulfonic acid. Compressive strength of crosslinked fiber was about 20% better than that of unmodified PBO fiber. In another experiment, 10 mol % of 2,5-diphenylsulfideterephthalic acid was incorporated into PBO fiber. The side chain of one phenyl sulfide unit was too short to enhance crosslinking, and the fiber had about the same compressive strength as unmodified PBO fiber. © 1995 John Wiley & Sons, Inc.
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  • 92
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 143-157 
    ISSN: 0887-624X
    Keywords: anionic polymerization ; polybutadienes ; trialkyltin lithium ; trialkyltin termination ; 119Sn-NMR ; 2,1-initiation ; 1,2-napthoquinone ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Low molecular weight polybutadienes and styrene butadiene copolymers were anionically prepared with trialkyltin lithium initiator and end-capped with either hydrogen or a trialkyltin group. These polymers were prepared with a variety of microstructures. Analysis by 119Sn-NMR and comparison to model compounds showed no cis-1,4-initiation of the butadiene. The initiation sites found were trans-1,4- and both 2,1- and 1,2-additions of the tin-lithium bound to a 1,3-butadiene. At low levels of added polar modifier, the 2,1-addition predominated. The 119Sn-NMR spectra allowed the assignment of the sequence distribution associated with the nearest eight main chain carbon atoms (2-4 monomer units) adjacent to the tin end groups. No initiation could be detected involving the styrene comonomer, but incorporation of styrene was detected as the first or second unit after initiation. The reaction of the allyl-tin end groups of these polymers with 1,2-napthoquinone was followed by NMR and was used to assign the peaks associated with 1,2-addition of the trialkyltin lithium to 1,3-butadiene. © 1995 John Wiley & Sons, Inc.
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  • 93
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 165-173 
    ISSN: 0887-624X
    Keywords: segmented ; azoxy polyester ; polyoxypropylene 400 ; ratio of chain lengths ; thermotropic properties of mesophase ; flexible domain effects ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this study a series of a segmented copolyester, poly(4,4′-dioxy-2,2′-dimethyl-azoxybenzene dodecanedioyl) (PMABD)-co-polyoxypropylene 400 (POP), was prepared. The chain length of PMABD studied (n) was varied from 7.8-18.2, and that of POP was unchanged. The intrinsic viscosity of the segmented copolyesters was 1.04-1.30, and the number average molecular weight obtained was 2.53 × 104-3.49 × 104 g/mol. The mesophase texture and thermal properties of the segmented copolyesters were measured as functions of n. It was found that the insert of flexible POP between those liquid crystalline domains of PMABD did affect thermotropic properties of PMABD. As the n value was 9.0 and 7.8 (or 7.4 and 8.6% by weight POP) the texture appeared as cholesteric-like oily streaks. The effect could not be attained by simply copolymerizing a mesogenic moiety with a pair of spacers of different lengths. The fluidity and domain structure of the flexible dodecanedioyl-POP-dodcanedioyl segments are taken into account for the obtained results. © 1995 John Wiley & Sons, Inc.
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  • 94
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 185-188 
    ISSN: 0887-624X
    Keywords: monomer sequence distribution ; copolyesters ; reaction temperature ; addition time ; thermal properties ; diphenyl chlorophosphate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [no Abstract]
    Additional Material: 1 Ill.
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  • 95
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 175-184 
    ISSN: 0887-624X
    Keywords: epoxy-amine ; methacrylate ; acrylate ; prepolymers ; synthesis ; kinetics ; Michael reaction ; catalyst ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Epoxy-amine methacrylated prepolymers are prepared in a 1-step synthesis by the reaction of Bisphenol A diglycidyl ether, glycidyl methacrylate, and different diamines. The adaptation of these reactions to production processes with a reduced reaction time requires a kinetic control and the use of efficient catalysts. The comparative kinetic treatment of the epoxy-amine reaction in the frame of Horie's and Rozenberg's kinetic schemes have been made. Cases where an efficient acid catalyst is used are also examined. Structural studies of these reactions established the occurrence of a Michael amine/double bond addition, when some amines are used. © 1995 John Wiley & Sons, Inc.
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  • 96
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 197-201 
    ISSN: 0887-624X
    Keywords: anthryl methyl vinyl ketone ; polymer ; photolysis ; drug delivery ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photolysis of copolymers of anthrylmethyl vinyl ketone (AMVK) with styrene and methyl methacrylate has been studied, both in solution and in the solid phase. Quantum yields of the order of 0.01 were observed in both cases for release of the major product, methyl anthracene (MA). Photolysis of an aqueous emulsion of a styrene-AMVK copolymer showed similar yields of MA. The results indicate the possibility of using the Norrish type I process as a means of releasing drugs or other biologically active compounds from polymeric matrices. © 1995 John Wiley & Sons, Inc.
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  • 97
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 189-196 
    ISSN: 0887-624X
    Keywords: thermotropic polymers ; liquid crystalline polymers ; semi-rigid spacer ; melt processable liquid crystal ; nematic ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly[oxy(2-methyl-1,4-phenylene)oxyterephthaloyl-co-oxymethylene-1,4-cyclohexylene-methyleneoxyterephthaloyl] was synthesized using a solution-based process. This copolyester has cyclohexylene dimethylene as a semi-rigid spacer along the polymer main chain to interrupt the inherent rigidity of the system while preserving the mesogenicity of the macromolecules. Polymer characterization includes elemental analysis, Fourier transform infrared spectroscopy, nuclear magnetic resonance, hot-stage polarized light microscopy, wide-angle x-ray diffraction, dilute solution viscometry, differential scanning calorimetry, and thermogravimetric analysis. This copolyester shows nematic liquid crystalline behavior in polarized light above about 240°C. The intrinsic and inherent viscosities are 0.88 and 0.68 dL/g respectively. The observed melting temperature of this copolyester is about 265°C, but melting begins as low as 215°C, making the polymer readily melt-processable. The degradation temperature is about 340°C under a nitrogen atmosphere. © 1995 John Wiley & Sons, Inc.
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  • 98
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 203-210 
    ISSN: 0887-624X
    Keywords: chelating resin ; poly(hydroxamic acid) ; ethyl acrylate ; hydropholic crosslinking agent ; metal binding properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Porous poly(hydroxamic acid) chelating resin was prepared by the reaction with poly(ethyl acrylate) crosslinked with divinylbenzene and hydrophilic crosslinking agent, and hydroxylamine. The hydrophilic crosslinking agents and diluent used in this article were ethylene glycol dimethacrylate or butanediol dimethacrylate, and 2,2,4-trimethyl pentane, respectively. The characterization of this type chelating resin was carried out by IR spectroscopy, density measurement, and scanning electron microscopy. Various metal binding properties such as extraction, kinetics, and selectivity were investigated with atomic absorption spectrometer and inductively coupled plasma spectrometer. Poly(hydroxamic acid) resins crosslinked with mixed crosslinking agents showed better metal extraction properties and faster adsorption rate than those crosslinked with divinylbenzene alone. And alkali treatment enhances the binding rate for metal ions because of the formation of other chelating ligands or micropores. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 99
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 239-246 
    ISSN: 0887-624X
    Keywords: organosilicon polymer ; polycarbosilane ; protodesilylation ; silytriflate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polycarbosilanes obtained by the Wurtz method or Grignard synthesis were converted by protodesilylation with trifluoromethanesulfonic acid to triflate-substituted derivatives. Reactions of these polymers with nucleophiles led to novel functionally substituted polycarbosilanes. Polycarbosilanes with a regular alternating arrangement of silicon and carbon atoms, however, could not be obtained by this procedure. Such polymers were prepared by reactions of bis(trifluoromethylsulfonyioxysilyl)methanes with dinucleophiles. All syntheses are characterized by a high regioselectivity and high yields at low temperatures in short reaction times. The structures of the polymers were proven by NMR spectroscopy (29Si, 13C, 1H). © 1995 John Wiley & Sons, Inc.
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  • 100
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    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 211-225 
    ISSN: 0887-624X
    Keywords: liquid crystalline polymer ; thermotropic ; nematic ; synthesis ; characterization ; solubility ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Wholly aromatic, thermotropic homopolyesters, derived from 4,4′-biphenol, substituted biphenols, or 1,1′-binaphthyl-4,4′-diol and 3,4′-benzophenone dicarboxylic acid, and two copolyesters, each of which contained 30 mol % of 6-hydroxy-2-naphthoic acid, were prepared by acidolysis polycondensation reactions and characterized for their liquid crystalline properties. The solubility behavior of these polymers has also been investigated. The two homopolymers of phenyl-substituted biphenols with 3,4′-benzophenone dicarboxylic acid were soluble in many common organic solvents. All of the homopolymers had lower Tm/Tf values than those with terephthalic acid, which was attributed to the incorporation of the asymmetric 3,4′-benzophenone dicarboxylate units in a head-to-head and head-to-tail fashion along the polyester chain. Two copolymers had lower Tm values than those of the respective homopolymers, as expected. They formed nematic phases which persisted up to 400°C, except those of phenyl-substituted biphenols with 3,4′-benzophenone dicarboxylic acid. Each of these two polymers also exhibited an accessible Ti transition, and had a broad range of LC phase. They had glass transition temperatures, Tg, in the range of 139-209°C and high thermal stabilities in the temperature range of 465-511°C. © 1995 John Wiley & Sons, Inc.
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