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  • 1985-1989  (16)
  • 1960-1964
  • 1986  (16)
  • Polymer and Materials Science  (12)
  • Life and Medical Sciences  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Investigation on the microstructure of poly(cyclohexyl α-chloroacrylate)s using 500 MHz 1H and 25 MHz 13C NMR (1986)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 187 (1986), S. 375-381 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The tacticity of poly(cyclohexyl α-chloroacrylate) (PCCA) was studied by 500 MHz 1H and 25 MHz 13C NMR spectroscopy. The influence of the polymer configuration was observed at three different carbon resonances: The backbone methylene carbon, the carbonyl carbon and the quaternary carbon. Tetrad tacticities of PCCA measured from the resonance of the backbone methylene carbon were in good agreement with tetrad values obtained by 1H NMR. The polymer obtained was syndiotactic rich and obeyed Bernoullian statistics in its tacticity distribution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1986.021870217
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  • 2
    Electronic Resource
    Electronic Resource
    Dielectric studies of the cure of epoxy matrix systems (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 1155-1167 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Dielectric spectroscopy was used to monitor the curing process of two epoxy resin systems. The basic system (system I) consisted of DGEBA (a difunctional epoxy) and a polyamide in a 50-phr mixture. In addition, a comparative analysis was performed on a high-performance resin system (system II) used primarily in unidirectional composite applications. This system contained TGDDM (a tetrafunctional epoxy) and DDS (a tetrafunctional amine) in a 25-phr mixture. The dielectric data were obtained using a simple yet functional sample cell electrode designed and constructed in the laboratory. For system I, isothermal dielectric data were used to determine apparent activation energies for the temperature range from 22 to 70°C. The data showed that the activation energy was a function of temperature and increased as the temperature of the cure increased. This indicated that the reaction mechanism was also a function of temperature. For system II, data were collected between 140 and 190°C and an overall activation energy for that temperature range was determined. The overall activation energies for both systems, calculated using dielectric spectroscopy, compared favorably to those obtained using differential scanning calorimetry. Also, using a wider frequency range (240 Hz to 2 MHz), Argand diagrams were constructed and modeled with the Cole-Cole empirical equation for systems with a distribution of relaxation times. This justified the calculation of average relaxation times, which could then be related to the bulk physical properties of the polymer, such as viscosity. Modified Argand diagrams, where ε″ is plotted against ε′ at one frequency as a function of time, were also constructed, which aided in the understanding of the curing processes for these thermosetting systems.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310501
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  • 3
    Electronic Resource
    Electronic Resource
    Acid-catalyzed degradation of poly(2-butyl-1, 3, 6-trioxocane) (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 2903-2917 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acid-catalyzed degradation of poly(2-butyl-1,3,6-trioxocane) (1) has been studied. With ethyl tosylate as the catalyst, the cyclic monomer 2 was the major product. The minor products are cis and trans isomers of C3H7CH=CH—OCH2CH2OCH2CH2OH, and three stereoisomers of C3H7CH=CH—OCH2CH2OCH2CH2O—CH=CH—C3H7 elucidated by 1H and 13C NMR, IR, electron impact and chemical ionization MS, and in the case of 2 also by comparison with an authentic sample. With 98% H2SO4 as the catalyst 2 is only a minor product. The major products are diethylene glycol, valeraldehyde, and 1,4-dioxane with some 2-butyl-1,3-dioxolane. Capillary GC/mass spectrometry led to identification of the following less abundant products: tri-n-propylbenzene, α,β-unsaturated aldehydes, and cyclic dimer. The products of H2SO4-catalyzed decomposition of polymer were also obtained by heating monomer 2 with H2SO4. A detailed mechanism for the formation of the eight-member ring 2 in the decomposition is proposed which involves unzipping proceeds via open carbocation intermediates. According to the principle of microscopic reversibility, the same open carbocation is the propagating species in the polymerization of 2 under similar conditions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080241118
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  • 4
    Electronic Resource
    Electronic Resource
    Thermo-oxidative decomposition of poly (ether ether ketone) (1986)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 24 (1986), S. 641-644 
    Details
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1986.140241204
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  • 5
    Electronic Resource
    Electronic Resource
    Magnesium chloride supported high-mileage catalysts for olefin polymerization. X. Effect of hydrogen and catalytic site deactivation (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 2707-2727 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of H2 on propylene polymerization initiated by a MgCl2/EB/PC/AlEt3/TiCl4-3 AlEt3/MPT catalyst was studied. Hydrogen increases significantly the initial rate during the early stage of the polymerization to give a higher yield of polymer than reactions without H2. But H2 reduces the yield toward the latter stages so that the net effect on the total yield can be quite small. There is no appreciable effect of H2 on either the isotacticity index or polydispersity of the products. It decreases molecular weight proportional to (pH2)1/2. The chain transfer by H2 resulted in a decrease of total metal polymer bond concentration with time of polymerization. The rate constants of hydrogen chain transfer for the two kinds of isospecific and nonspecific sites are \documentclass{article}\pagestyle{empty}\begin{document}$ k_{tr1^{\rm i}}^{\rm H} $\end{document} = 5.1 × 10-3, \documentclass{article}\pagestyle{empty}\begin{document}$ k_{tr2^{\rm i}}^{\rm H} $\end{document} = 2.7 × 10-3, \documentclass{article}\pagestyle{empty}\begin{document}$ k_{tr2^{\rm a}}^{\rm H} $\end{document} = 7.5 × 10-3, \documentclass{article}\pagestyle{empty}\begin{document}$ k_{tr2^{\rm a}}^{\rm H} $\end{document} = 4.4 × 10-3, in units of torr1/2 sec-1 at 50°. Hydrogen assists in the deactivation of the catalytic sites as does propylene; rates of the former and the latter vary with (pH2)1/2 and [C3H6]1/2, respectively, with ktH = (12.1 ± 0.9) M-1 torr-1/2 sec-1 and ktM = (65.3 ± 3.3) M-3/2 sec-1 at 50° and A/T = 167. The mechanism for deactivation of catalytic sites are discussed.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080241101
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  • 6
    Electronic Resource
    Electronic Resource
    Magnesium chloride-supported high-mileage catalysts for olefin polymerization XI. Determinations of poly(decene-1) molecular weight chain dimension and thermal transitions (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 2217-2230 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Decene-1 was polymerized with the CW catalyst and fractionated by precipitation technique. Light-scattering and viscometric measurements on these fractions established the relationship [η] = 5.19 × 10-3 Mw0.77. The unperturbed mean square end-to-end distance is (〈Ro2〉/M)1/2 = (6.17 ± 0.34) × 10-9. Light-scattering data is consistent with a relatively stiff molecule with length of L = 1.75 × 10-5 cm for poly(decene-1) with MW = 397,000. Its mean square radius of gyration 〈Rg2〉 is 2.79 × 10-11 cm.2 The ratio of L2/〈Rg2〉 = 11 is close to the theoretical ratio of 12 for this kind of macromolecule.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240916
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  • 7
    Electronic Resource
    Electronic Resource
    Magnesium chloride supported high mileage catalysts for olefin polymerization. XIII. Effect of external Lewis base on ethylene polymerization (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 1967-1988 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of external Lewis base (Be) on the polymerization of ethylene by the MgCl2/ethyl benzoate/p-cresol/AlEt3/TiCl4 catalyst was studied by activation with AlEt3 alone without the use of methyl-p-toluate. The initially formed active site concentration, [Ti1*], is about doubled in the absence of Be; at 50°C about 93% of the total titanium became catalytic. The same increment of [Ti2*] was observed without Be. The rate constants of propagation are not appreciably affected by Be; the values are the same at 50° with and without Be. At other temperatures the kp values are somewhat smaller without Be. One major effect was the very large ktrA values for chain transfer with aluminum alkyls in the absence of Be as compared to those with Be. This can be attributed to the greater monomeric AlEt3 concentration in the former, but in much smaller amounts in the presence of Be due to complexation. The rate constants of chain transfer with hydrogen are not much affected by Be. However, the termination rate constants are generally much smaller when Lewis base is not present.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240818
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  • 8
    Electronic Resource
    Electronic Resource
    Magnesium chloride supported high-mileage catalyst for olefin polymerization. IX. Molecular weight and distribution and chain-transfer processes (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 1779-1818 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mn, Mw and PD = Mw/Mn of polypropylene obtained with the MgCl2/ethyl benzoate/p-cresol/AlEt3/TiCl4-AlEt3/methyl-p-toluate (CW-catalyst) have been obtained as a function of temperature, monomer, and AlEt3 concentrations. The values of Mn after a few minutes of polymerization range from 50% to 100% of the final values. I.I. (percent yield of stereoregular polymer) and P.D. of stereoregular polymer remain constant during a batch polymerization. The MW distribution is very narrow with PD ⋍ 2.0 between 0° and 50° using optimum A/T ratio. It is broader for polymerizations employing low or high A/T ratio or elevated temperature, reaching P.D. = 2.78 at 70°C. The corresponding P.D. values for the total polymer ranged from 3.1 to 4.5 due to contributions from the heptane soluble fraction. The latter gives bimodal GPC chromatogram. The Mn of stereoregular polymer is much smaller than the reciprocal of concentration of metal polymer bonds, [MPB]-1; the ratio of the two quantities is a measure of number of polymer chains not bonded to a metal ion to the number of those which are bonded to either Ti or Al. Depending upon the experimental conditions, this ratio varied from 2.3 to 23.5 for short polymerization time, and 16 to 31 for long polymerization time.Chain transfer with AlEt3 is ineffective for the CW-catalyst system. From the plots of [MPB] versus yield, the rate constants for this process obtained at 50° are: ktr1iA = 2.1 × 10-4 sec-1; ktr1aA = 2 × 10-5 sec-1; ktr2iA = 1.1 × 10-4 sec-1; and ktr2aA = 1.2 × 10-5 sec-1 where the subscripts i, a, 1 and 2 refer to stereospecific and nonstereospecific sites of first and second kind respectively. Thr transfer rates increase with both increasing and decreasing temperatures consistent with the Langmuir-Hirschelwood adsorption model.The MW of isotactic polymers are dependent upon monomer concentration. The chain transfer with monomer has rate constants at 50° of ktr1iM = 1.34 × 10-2 M-1 sec-1 and ktr2iM = 1.2 × 10-3 M-1 sec-1. In addition there is chain transfer by β-hydride elimination with ktr,iβ = 2.7 × 10-2 sec-1 at 50° which is the chain lifetime limiting process at low monomer concentration. The rate of chain transfer with monomer can exceed that of β-hydride elimination at high propylene pressure.The very narrow PD for the stereoregular polymers suggest there is only one chemically distinct isospecific active site.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240805
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  • 9
    Electronic Resource
    Electronic Resource
    Magnesium chloride supported high mileage catalysts for olefin polymerization. XII. Polymerization of ethylene (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 2483-2505 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerizations of ethylene by the MgCl2/ethylbenzoate/p-cresol/AlEt3 TiCl4-AlEt3/methyl-p-toluate (CW-catalyst) have been studied. The initially formed active site concentration, [Ti1*] has a maximum value of 50% of total titanium at 50°C and lower values at other temperatures. The Ti1* decays rapidly to Ti2* sites with conc. ca. 10 mol %/mol Ti. The rate constants for four chain transfer processes have been obtained at 50°C: for transfer with AlEt3, ktr, 1A = 2.1 × 10-4 s-1 and ktr, 2A = 4.8 × 10-4 s-1; for transfer with monomer, ktr, 1M = 3.6 × 10-3 (M s)-1 and Ktr, 2M = 8.3 × 10-3 (M s)-1; for β-hydride transfer, ktr, 1β = 7.2 × 10-4 s-1 and ktr, 2β = 4.9 × 10-4 s-1; and transfer with hydrogen, ktr, 1H = 4.0 × 10-3 torr1/2 s- and ktr, 1H = 5.1 × 10-3 torr1/2 s-1. The rate constants for the termination assisted by hydrogen is ktr1H = 1.7 (M1/2 torr1/2 S)-1. If monomer is assisting termination as was observed for propylene polymerization, then ktM = 7.8 (M3/2 s)-1. Values of all the rate constants can be higher or lower at other temperatures. Detailed comparisons were made with the results of propylene polymerizations. There are more than four times as many Ti1* active sites for ethylene polymerization than there are for stereospecific polymerization of propylene; the difference is more than a factor of two for the Ti2* sites. Certain rate constants are nearly the same for both monomers while others are markedly different. Some of the differences can be explained by stereoelectronic effects.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080241010
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  • 10
    Electronic Resource
    Electronic Resource
    SN-conducting polymers with heterocyclic spacer groups (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 2947-2957 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymer-containing alternating sulfur nitrogen moieties separated by heterocyclic groups have been synthesized and characterized. The polymers have undoped conductivities of 10-6 to 10-9 (Ω cm)-1; the intrinsic carriers are negatively charged as shown by thermopower coefficient of -1.4 × 103 to -1.9 × 103 μV K-1. The polymers are degraded by AsF5 and cannot be doped by iodine. Exposure to bromine resulted in reversible p-doping of the SN polymers to the thermopower values of +400 to +820 μV K-1 and conductivities of 0.01 to 0.002 (Ω cm)-1. Removal of dopant by evacuation returns most of the properties of the polymers to the undoped states. Magnetic properties of the materials have been studied.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080241122
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