摘要:

AbstractViscosities of samples of poly(vinyl chloride) in cyclohexanone were measured over a wide range of concentrations, up to polymer weight fractions of the order of 0.4. Polymers with molecular weight from 10,000 to 230,000 and with different molecular weight distributions were studied. The effect of concentration and molecular weight on the solution viscosity is reported and discussed for this systems, as well as for other systems for which data are available in literature. The empirical reduction schemes often applied to the viscometric data of concentrated polymer solutions are discussed.

ISSN:0021-8995    

DOI:10.1002/app.1966.070100101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractThe Kelley‐Bueche free‐volume treatment of the viscosity of polymeric solutions has been applied to the previously reported data on poly(vinyl chloride)‐cyclohexanone solutions and to several other polymer‐diluent systems. It has been shown that the theoretical equations, based on the assumption of the additivity of free volumes of the components, are capable of predicting with remarkable accuracy the concentration, temperature, and molecular weight dependence of the viscosity of the investigated solutions over very large ranges of the va

ISSN:0021-8995    

DOI:10.1002/app.1966.070100102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractThe phenomenon of ozone cracking has been investigated for elastomer blends containing an ozone‐reactive phase (natural rubber) and an ozone‐inert phase (ethylene–propylene rubber). Electron microscopical studies reveal phase separation in the blend and the locus of ozone attack. Ozone cracks traverse the reactive phase and occasionally jump across inert particles without severing them. This mechanism provides the basis of a theory which correctly predicts the dependence of both the critical stored energy for ozone cracking and the crack density upon the blend compos

ISSN:0021-8995    

DOI:10.1002/app.1966.070100103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractDiffusion of small quantities of liquids in porous polymeric substrates has been studied by means of a radiotracer technique. The procedure has been applied to the permeation of five different types of paper stock by ethylene‐1,2‐C14glycol. Data obtained indicate that under the experimental conditions the diffusion analogy is valid for solvent penetration in the systems studied. The method should have general applicability to studies of diffusion rates in cellulosic and other membranes and to investigations where only small quantities of diffusant are availa

ISSN:0021-8995    

DOI:10.1002/app.1966.070100104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractRelaxation times of polyethylene melts have been measured by Aloisio, Matsuoka, and Maxwell. One implication regarding their observations is that the elastic properties of polymer melts must be time‐dependent. In particular, the steady‐flow shear modulus depends on the strain rate. Some interpretations of data in the literature have been based on concepts in rubber elasticity where the steady‐flow modulus is an equilibrium value, independent of strain rate. We have used Pao's theory for viscoelastic flow together with measurements of relaxation times to discuss the strain rate dependence of the steady‐flow shear modulus of melts. The existence of a strain rate‐dependent shear modulus leads naturally to a nonlinear relation between shear stress and recoverable shear strain. The conclusions regarding the molecular weight dependence of the modulus also differ from interpretations based on rubber e

ISSN:0021-8995    

DOI:10.1002/app.1966.070100105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractA semiquantitative method for assessing the amount of visible solid matter in polyethylene latexes is described. As judged by this method and by the presence of particles larger than 50 μ, the stability of the latexes was related to (1) the type and concentration of post‐emulsifier added to the latex, (2) the average size of the polymer particles, and (3) the concentration of solids. Generally, the appearance was better when the latexes had a low (30%) concentration of solids, a large (800 A.) average particle diameter, and enough post‐emulsifier to cover most of the polymer surface. Specific samples, however, having a high (36%) concentration of solids and a small (300 A.) average particle diameter also showed good storage stability. According to tests on selected latexes, good resistance to coagulation by mechanical shear was obtained only if the surface of the polymer was completely covered with emulsifier. When polyethoxylated alkylphenols were used as post‐emulsifiers, an inverse relation appeared to exist between latex stability and average number of ethylene oxide units per emulsifier molecule. Moreover, the addition of each ethylene oxide group increased the apparent area of the emulsifier molecule by abou

ISSN:0021-8995    

DOI:10.1002/app.1966.070100106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractBy the use of simple models of filled plastics, approximate equations are derived for the elongation to break in the case of perfect adhesion between the phases and for the tensile strength in the case of no adhesion between the polymer and filler phases. By combining these equations with equations for the modulus (assuming Hookean behavior) all the stress–strain properties can be derived, including rough estimates of the impact strength, as a function of filler concentration. Among other things, the theory predicts a very rapid decrease in elongation to break as filler concentration increases, especially for the case of good adhesion. It is also predicted for the case of good adhesion that the tensile strength of a filled polymer can be greater than that of an unfilled polyme

ISSN:0021-8995    

DOI:10.1002/app.1966.070100107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractThe thermally induced solid‐state polymerization of 66 nylon was investigated. It was found that the rate‐controlling step in the process is chemical reaction. A mechanism of the form, rate =ktnwas shown to hold. The reaction rate constant was found to bek= 1.53 × 1010exp [ − 12,960/RT]. Units ofkare (hours)−0.51. Activation energy determined in this work compared closely to that determined for nylon 6 solid‐state poly

ISSN:0021-8995    

DOI:10.1002/app.1966.070100108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractAn attempt was made to evaluate the apparent elastic constant of a two‐phase systemGfrom those of the components of the system. The modulusGis expressed as follows:\documentclass{article}\pagestyle{empty}\begin{document}$ G = G_1 \frac{{\left( {7 - 5v_1 } \right)G_1 + \left( {8 - 10v_1 } \right)G_2 - \left( {7 - 5v_1 } \right)\left( {G_1 - G_2 } \right)v}}{{\left( {7 - 5v_1 } \right)G_1 + \left( {8 - 10v_1 } \right)G_2 + \left( {8 - 10v_1 } \right)\left( {G_1 - G_2 } \right)v}} $\end{document}whereG1andG2are the shear moduli of the suspending medium and the suspended particles, respectively,v1is the Poisson ratio of the medium, andvis the volume fraction of the particles. The results for modulus were extended to dynamic viscoelasticity by the corresponding principle. Experimental verifications with dynamic viscoelasticity data were conducted for the system of styrene‐acrylonitrile copolymer interpolymerized with polybutadiene particles. For shear viscosity comparisons with experiment were made for the system linear polyethylene‐polybut

ISSN:0021-8995    

DOI:10.1002/app.1966.070100109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractPolyethylene and polypropylene films were irradiated by γ‐irradiation from a Co60source in butadiene gas flow and in liquid butaidne. Irradiating in the butadiene gas flow is particularly convenient because the gas state monomer is available directly and little homopolymer is produced. In this case, there is a retardative effect on the grafting near the surface of the film and the grafting rate shows the maximum values at 50–60°C. for high‐density PE (PEH) and PP. Irradiating in the liquid butadiene decreases the retardative effect near the surface. The effect of dose rateIon the grafting rateRpis represented byRp∞I1/4in this case. The grafting rate is always higher in PEH than in low‐density PE (PEL). Results of x‐ray diffractometry and electron microscopy indicate that the grafting reaction occurs predominantly near the surface of the crystallite (lamella) of PE and the grafting rate is not affected by the overall crystallinity of the trunk polymer but by the configurational structure, such as the degree of branching or side

ISSN:0021-8995    

DOI:10.1002/app.1966.070100110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY