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6613480 
Journal Article 
RELAXATIONAL AND OPTICAL-PROPERTIES OF POLYDIMETHYLSILOXANE POLYVINYLTRIMETHYLSILANE POLYDIMETHYLSILOXANE TERNARY BLOCK-COPOLYMER 
Grishchenko, AE; Turkov, VK; Semenov, OB; , 
1993 
1 
Vysokomolekylyarnye Soedineniya. Seriya A
ISSN: 0507-5475 
MEZHDUNARODNAYA KNIGA 
MOSCOW 
B878-B882 
WOS:A1993LT77400019 
The properties of polydimethylsiloxane- polyvinyltrimethylsilane-polydimethylsiloxane ternary block copolymers with different concentrations of components are studied. Two temperature regions of dielectric losses are found near -120 and +200-degrees-C, which correspond to the glass transition temperatures of the components. The concentration dependence of the maximum values of tan delta(max) corresponding to the alpha-relaxation process in PDMS is S-shaped. At concentrations w less than 0.2, PDMS forms a dispersed microphase; at w > 0.6, PVTMS forms a dispersed microphase. In the intermediate region 0.2 < w < 0.6 both microphases form partially interpenetrating continuous structures.An essentially nonlinear concentration dependence of the block copolymer photoelasticity coefficient was found, which is explained by the effect of the shape. A formula describing the concentration dependence of the effect of the shape is proposed, which allows one to estimate the size of PVTMS aggregations. Microphase separation in the block copolymers studied occurs on the molecular level.