抄録
Structural relaxation processes in amorphous poly (ethylene terephthalate) (PET) and in amorphous lightly branched PET of ethylene terephthalate-trimellitic (TMA) copolyesters at temperatures below their glass transition temperatures (Tg) have been monitored by dilatometric volume measurements of the polymer glasses after they were subjected to several different thermal histories. Both of thermal annealing at temperatures above Tg and chain branching due to incorporation of TMA into PET were found to cause appreciable decreases in the effective volume relaxation time. A new molecular kinetics model of structural relaxation was presented to provide a unified interpretation of the experimental results.
