ANNEALING DURING POLYMERIZATION OF CRYSTALLINE POLY(ETHYLENE TEREPHTHALATE)

Mel-crystallized poly(ethylene terephthalate) and etched oligomer lamallae from the same polymer have been annealed under vacuum at temperatures between 200 and 260C and times between 3 and 48 hr. The annealed samples were analyzed through determination of viscosity-average molecular weight, x-ray low-angle spacing, density, heat of fusion, and variation of melting point with heating rate. In all cases it could be shown that the crystal lamellar surfaces remained chemically reactive. Chain folds and chain ends in the surface were converted by chemical reaction to tie molecules between different crystals or different locations on the same lamella.