Degradation mechanism and morphological change of PET by PEG–diamine

The aminolysis mechanism and morphological change were investigated with NMR, IR, GPC, density, and other physicochemical methods when the biaxially drawn PET film was aminolyzed with PEG–diamine at 130°C. By the aminolysis reaction, the PET chain end was capped with PEG chain as the following equation: magnified image Molecular weight showed a rapid decreasing tendency in the initial stages of the aminolysis reaction. The crystallinity, measured by density and IR methods, increased with the reaction time mainly due to the recrystallization of the amorphous PET chain promoted by better chain mobility of the PEG‐terminated PET. The fold period of the chain‐folded lamellar crystal formed through recrystallization was the same as that of the original PET lamellar crystal. It was found that 74% of all the capped PEG chains were located in the amorphous region, 18.4% at the initial point from which the recrystallized lamellar crystal began to grow, and the rest in the lamellar crystalline lattice.