REACTIVE COMPATIBILIZATION OF POLYESTER VINYL-ACETATE COPOLYMER BLENDS - RHEOLOGICAL, MORPHOLOGICAL AND MECHANICAL-PROPERTIES

The 'in situ' compatibilization of poly(ethylene terephthalate) (PET) copolymer (PETG) with ethylene vinyl acetate (EVA) copolymer via catal ysed transesterification reactions was examined through rheological, m orphological and mechanical studies. The addition of dibutyltin oxide catalyst was found to diminish the size of the dispersed phase, enhanc e its adhesion with the matrix and lead to an increase in the dynamic elastic modulus (G') with temperature. This improvement in adhesion al so results in a considerable increase in the elongation at break, from 20 to 140% when 2.4 wt% of catalyst is added to a 70/30 PETG/EVA blen d. The comparative behaviour of blends with and without catalyst is ex plained via copolymer formation at the interface and co-crosslinking o f EVA and PETG chains.