THE STRUCTURE OF ORDERED PHASES IN POLYDI PHENYLSILOXANE

Polydiphenylsiloxane can form three ordered phases: two crystalline ph ases and the mesophase. Phase I, which is obtained when polydiphenylsi loxane is obtained by solid-phase polymerization or when the polymer i s crystallized from a solution in diphenyl ether, is a rather disorder ed Crystalline tetragonal modification with the unit cell parameters a = 1.02 nm and c = 0.99 nm. Phase II, which is formed when the polymer is crystallized from the mesomorphic state, is a thermodynamically eq uilibrium crystalline phase. It belongs to monoclinic symmetry system and is characterized by the following unit cell parameters: a = 2.133 nm, b = = 0.991 nm, c = 2.03 nm, and gamma = 108.9 degrees. Phase III (the mesophase) is presumably a two-dimensionally ordered columnar pha se.