Influence of backbone structure on the glass transition characteristics of semiflexible polymers

The glass transition characteristics of two groups of semiflexible copolymers incorporating meta linkages in the chain backbone have been investigated as a function of copolymer composition and crystallization history. The introduction of meta-phenylene linkages into the backbone of poly (phenylene sulfide) and poly (ether ketone ketone) leads to a loosening of the constraint which is imposed on the amorphous chains by the crystalline phase in these semicrystalline materials. This is manifested by a decrease in glass transition offset with increasing meta content, and the full mobilization of rigid amorphous material for less restrictive crystallization conditions.