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:
The temperature dependence at constant frequency of the viscous component E2(1/T) of the dynamic modulus has been determined for a homologous series of butadiene-acrylonitrile copolymers supported in a matrix of styrene homopolymer. The results, which agree with those reported earlier for a homologous series of butadiene-styrene copolymers, indicate that the transition temperature of a given plastic homopolymer, as measured from dynamic mechanical properties at essentially constant frequency in the range 200-300 cycles/sec., is depressed by the presence of a copolymerized rubbery diluent as the melting point of crystalline polymers is depressed by the presence of noncrystallizing comonomers. In addition, it has been found that the transition temperature is depressed by the presence of monomeric diluents much as the melting point of crystalline polymers is depressed by the presence of monomeric diluents. Two earlier assumptions, that the dynamic properties in the frequency range of interest should be independent of both the molecular weight of the rubbery copolymer and the degree of dispersion of the copolymer in the thermoplastic matrix, have been subjected to experimental scrutiny. The assumption regarding the dependence on molecular weight has been substantiated, at least for DP's in excess of 100. The assumption regarding the dependence on the degree of dispersion has been negated; the area under the E2(1/T) peak was found to be considerably greater for a coarse dispersion than for a fine one.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1963.070070410
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