Phase aggregate states of multiblock siloxaneimide block copolymers

Poly(siloxane imides) with a short rigid block containing only one imide un it may be considered as multiblock block copolymers, which experience micro phase segregation of blocks. Effect of the number of dimethylsiloxane units in the flexible block on the phase aggregate state and the character of ph ase segregation in poly(siloxane imides) was studied. The region of critica l content of dimethylsiloxane units in flexible block, where transition fro m the structure with microphase separation of blocks to a single-phase stru cture takes place, was found. The molecular weight and the parameter of ent anglement network M-e of the polymers were calculated. These calculations e xplain deviation of the temperature of the alpha-transition in the imide bl ock of poly(siloxane imide) from the temperature of the alpha-transition in the corresponding polyimide.