ISSN:
1435-1528
Keywords:
Polymer melt
;
dynamic moduli
;
flow birefringence
;
stress-optic rule
;
rheo-optical investigation
;
polymer blend
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Abstract The dynamics of the individual components in 1,4-polyisoprene/polyvinylethylene (PIP/PVE) miscible blends are studied using dynamic stress-optical measurements. While the homopolymers are thermorheologically simple and obey the stress-optic rule, the blends show failure of time-temperature superposition and complex stress-optic behavior. The way in which the stress-optic rule fails reveals the relaxation dynamics of each species. The dynamic modulus and complex birefringence coefficient are analyzed to infer the relaxation of each component. The entanglement molecular weight, M e , and monomeric friction coefficient, ζ0, of each species as a function of blend composition and temperature are determined from the contribution of each species to the dynamic modulus. The effect of blending on M e of each component is small; however, its effect on ζ0 of each species is dramatic. Blending strongly speeds the rate of relaxation of the high T g component (PVE), while more modestly slowing the relaxation of the low T g component (PIP). The dynamics of each species have different temperature dependencies in the blend, which leads to the failure of the superposition principle. Furthermore, both the difference between the friction coefficients of the two species and the difference in their temperature dependencies is greater in blends rich in the high T g material (PVE).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00366959
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