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  • Polymer and Materials Science  (464)
  • Wiley-Blackwell  (464)
  • 1995-1999  (226)
  • 1980-1984  (238)
  • 1997  (226)
  • 1980  (238)
  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 2925-2933 
    ISSN: 0887-6266
    Keywords: ionic conductivity ; DC conductivity ; rigid-rod polymer ; depletion measurement ; X-ray scattering ; anisotropic ; polymer electrolyte ; polyelectrolyte ; conducting polymers ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The conductivity study results of lithium-doped sulfonated PBI, a conjugated rigid rod polymer, poly[(1,7-dihydrobenzo[1,2-d:4,5-d′]dimidazole-2,6-diyl)-2-(2-sulfo)-p-phenylene], derivatized with pendants of propane sulfonate Li+ ionomer are reported. The room-temperature DC four-probe conductivity parallel to the surface of cast films was as large as 8.3 × 10-3 S/cm. Similar measurements with an eight-probe configuration showed no difference between bulk and surface conductivity. The ionic nature of the conductivity was indicated by constant voltage depletion experiments and by secondary ion mass spectroscopy measurements of the residues near the electrodes. The DC two-probe conductivity measured transverse to the sample surface was three to four orders of magnitude smaller than longitudinal conductivity, while the AC two-probe conductivity was even less. Electron microscopy indicated that the films had a layered structure parallel to the surfaces. This structural anisotropy was confirmed by refractive index values obtained from wave-guide experiments and by wide angle X-ray scattering. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2925-2933, 1997
    Additional Material: 11 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 2 (1980), S. 5-10 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Mean free paths for inelastic scattering (λ) of low energy electrons in poly(methylmethacrylate) (PMMA) have been determined by measuring Al Kα excited C 1s and Si 2s photoelectron signal intensities as a function of ellipsometrically determined thicknesses of PMMA overlayers on silicon substrates. The λ values obtained are 29 ± 4 Å for 1196 eV electrons and 33 ± 5 Å for 1328 eV electrons. These data are necessary for the quantitative analysis of the surface region of PMMA and similar polymers by X-ray photoelectron spectroscopy (XPS). The magnitude of the λ values determined indicates that XPS measurements can provide chemical information about the surface region of polymers, such as PMMA, in the depth range of ∼6 to 100 Å. The results of this study are compared and discussed with respect to λ values determined for other organic compounds.
    Additional Material: 7 Ill.
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  • 3
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the poor solvent acetone/ethanol the viscosity of a 3% solution of 12.6% N pyro nitrocellulose is found to be related to the geometric mean of the number average and weight average molecular weights. The fractional increase in the viscosity of such a solution on the addition of lead ß-resorcylate is a function only of number average molecular weight. Once calibration has been made against osmotic pressure measurements and intrinsic viscosity, both number and weight average may be measured rapidly with an accuracy which is no less than that of the osmotic pressure and intrinsic viscosity measurements themselves.
    Additional Material: 3 Ill.
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  • 4
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of poly(ε-L-lysine) is described. This is a poly(ε-amino acid) in which the ε-amino group of lysine is condensed with the α-carboxyl group to produce a chain backbone that is a variant of the usual one seen in proteins and the side chain is the α-amino group. Conformational studies of poly(ε-L-lysine) and its t-butyloxycarbonyl derivative suggest the likelihood of a chain order that is formally similar to the antiparallel pleated-sheet conformation of proteins.
    Additional Material: 4 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 1841-1846 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The photo-oxidation of solid polymers at ambient temperatures is shown to be greatly affected by the low mobility of radicals in the solid state. When a radical pair, produced by photo-initiation, escapes the initial polymer cage, the probability of its recombination remains high even after several propagation steps. This phenomenon, known as secondary cage recombination, has a pronounced effect on the kinetics of oxidation and on the mechanism of photostabilisation by radical scavengers. The occurrence of secondary cage recombination is demonstrated for polypropylene photo-oxidation and a kinetic analysis is developed to predict the consequences of this effect.
    Additional Material: 2 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 25 (1980), S. 575-588 
    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: As part of a continuing study of nonisothermal rheology (meaning the simultaneous application of strain and temperature changes), we here consider the behavior of polystyrene near the glass transition temperature Tg. In particular, we measured the increase of the apparent Tg as the cooling rate is increased from 0.003 to 4.5°C/sec. This change (up to 16°C increase) has both practical and theoretical implications. For enhancing the mechanical properties of a glassy product, one desires maximum orientation (stress) just prior to quenching; the optimum deformation/temperature strategy for maximizing stress is affected by the level of Tg. By using a nonisothermal strategy we were able to produce higher frozen-in orientations, and thus higher mechanical properties, than have been previously reported. For a theoretical understanding of the rubbery state just prior to quenching, we used the generalized time-temperature superposition of our prior work; we found that a modified shift factor of the form aT(T,TRg), where TRg refers to a rate-dependent Tg, gives an improved fit to data but is not by itself adequate.
    Additional Material: 14 Ill.
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  • 7
    ISSN: 0887-624X
    Keywords: liquid polysulfide polymer ; hydrazine ; sodium tetrasulfide ; 1,1′-[methylenebis(oxy)]-bis-[2-chloroethane] ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results of our studies show that liquid linear polysulfide polymers of an average molecular weight 4260-1030 g mol-1 can be obtained by the reaction of sodium tetrasulfide and 1,1′-[methylenebis(oxy)]-bis-[2-chloroethane] in the presence of 2.0-5.0 mol of hydrazine and at least 4.0 mol of sodium hydroxide/mol of hydrazine in a one-step procedure. The disulfide polymers in the form of sodium mercaptide are soluble in the supernatant liquid from which they are separated by acidification of the solution to a pH value of about 4. The average molecular weight and the content of sulfur in the obtained linear polymers were determined and their IR spectra were recorded. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1363-1367, 1997
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  • 8
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 3457-3466 
    ISSN: 0887-624X
    Keywords: PBO ; rigid-rod polymer ; multidimensional polymer ; compressive strength ; fiber morphology ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A high-torque rheometer was used to facilitate the polycondensation of 4-[5-amino-6-hydroxybenzoxazol-2-yl]benzoic acid (ABA) with trimesic acid and 1,3,5,7-tetrakis(4-carboxylatophenyl)adamantane to yield two- and three-dimensional benzobisoxazole polymers, respectively. Although the resultant polymer dopes exhibited improved homogeneity compared to polymer dopes previously prepared in glassware, improved polymer solution viscosities were not achieved. Fibers spun from the two- and three-dimensional polymers did not show a significant increase in compressive strength compared to fibers of the linear or one-dimensional benzobisoxazole polymer derived from the homopolymerization of ABA. Morphological studies of the polymer fibers and films by wide-angle X-ray scattering and scanning electron microscopy strongly indicated more lateral disorder and a more isotropic character for the three-dimensional structures compared to the one-dimensional structures. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3457-3466, 1997
    Additional Material: 7 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2311-2321 
    ISSN: 0887-624X
    Keywords: styrene ; methyl methacrylate ; pulsed-laser polymerization ; “living” free radical ; propagation rate coefficient ; solvent effects ; benzyl alcohol ; N-methyl pyrrolidinone ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The free radical propagation rate coefficients of both Methyl Methacrylate (MMA) and Styrene (STY) have been measured using Pulsed-Laser Polymerization. The effect of solvents on the propagation rate coefficient, kp, is reported for several solvents, namely, bromobenzene, chlorobenzene, dimethyl sulphoxide, diethyl malonate, diethyl phthalate, benzonitrile, and benzyl alcohol, at 26.5°C. This preliminary data indicated that benzyl alcohol (BzA) had a large effect on the MMA propagation reaction. As earlier work indicated that N-methyl pyrrolidinone (NMP) would also have a large effect on the kp of MMA, Arrhenius parameters were evaluated for both MMA and STY at two different concentrations of monomer in BzA and NMP. BzA had a significant effect (at 95% confidence) increasing both the activation energy (Ea) and the preexponential factor (A) for MMA and STY. In NMP, a similar trend is observed for MMA polymerization; however, while a solvent effect on STY was observed, the effect on Ea and A was too small to discern with confidence. A series of additional experiments was performed to evaluate the influence of camphorsulfonic acid (CSA) as an additive in STY polymerization. There was no effect of CSA on kp, confirming that the strong effect CSA has on “living” radical polymerization of styrene does not originate from complexation leading to an accelerated propagation step but rather by altering the ratio of active-to-dormant chains in the reaction. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2311-2321, 1997
    Additional Material: 12 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 1077-1085 
    ISSN: 0887-624X
    Keywords: s-triazine ring ; thermal stability ; polyamide ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ten new aromatic polyamides containing s-triazine rings in the main chain were synthesized by the low temperature interfacial polycondensation technique involving the reactions of each of the two s-triazine containing diacylchlorides, viz., 2,4-bis (4-chlorocarbonylphenoxy)-6-methoxy-s-triazine and 2,4-bis(3-chlorocarbonylphenoxy)-6-methoxy-s-triazine, with five aromatic diamines namely, 4,4′-bis(4-aminophenoxy)diphenyl sulfone, 4,4′-bis(3-aminophenoxy)diphenyl sulfone, 2,2-bis[4(4-aminophenoxy) phenyl] propane, 1,4 bis (4-amino-phenoxy) benzene, and 1,3-bis (4-aminophenoxy)benzene. The resulting polyamides were characterized by viscosity measurements, IR and 1H-NMR spectroscopy, solubility tests, x-ray diffraction, and thermogravimetry. The polyamides had inherent viscosities in the range of 0.16-1.06 dL/g in N,N-dimethylacetamide at 30°C. Most of the s-triazine containing polyamides dissolved readily at room temperature in polar solvents. Except for the polyamide PA-2, the polyamides did not lose weight below 350°C under a nitrogen atmosphere. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1077-1085, 1997
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