Miscibility and interchange reactions in blends of bisphenol-A-type epoxy resin and poly(ethylene terephthalate)

Blends of diglycidyl ether of bisphenol A (DGEBA) and poly(ethylene terepht halate) (PET) were prepared by solution casting from 1,1,2,2-tetrachloroeth ane. The miscibility and interchange reactions in DGEBA-PET blends were stu died by differential scanning calorimetry (DSC) and optical microscopy. PET was found to be miscible with DGEBA, as revealed by the existence of a sin gle composition-dependence glass transition temperature (T-g). interchange reactions between DGEBA and PET components in the blends at elevated temper atures were proven by appearance of the enhanced glass transition temperatu res and the marked decrease in the crystallinity of PET. These results are attributed to the formation of copolymers based on the blend components due to interchange reactions. The morphological observations confirmed that th ere existed interchange reactions between DGEBA and PET. There also existed a self-crosslinking reaction among the DGEBA molecules. (C) 1999 John Wile y & Sons, Inc.