POLY(DIETHYLSILOXANE-CO-DIPHENYLSILOXANE AND YLSILOXANE-CO-3,3,3-TRIFLUOROPROPYLMETHYLSILOXANE) - SYNTHESIS, CHARACTERIZATION AND LOW-TEMPERATURE PROPERTIES

Copolymers containing diethylsiloxane and functional siloxane groups o f the form RR'SiO (where R, R' = phenyl, and R = methyl, R' = 3,3,3-tr ifluoropropyl) were synthesized by equilibrium polymerization of the a ppropriate cyclotrisiloxanes in the presence of KOH. Quantitative Si-2 9 n.m.r. spectroscopy indicated that the copolymers possessed random m icrostructures. D.s.c. and dynamic mechanical analysis show that both substituents are effective in lowering the crystal melting and low-tem perature crystal-crystal transitions with respect to the diethylsiloxa ne homopolymer, and ultimately lead to non-crystalline copolymers.