Abstract: In this paper,chain extenders were added to poly(ethylene terephthalateco1,4cylclohexylenedimethylene terephthalate)(PETG) to improve its melt strength and viscosity through reactive processing. Effect of chain extenders on structure and rheological behavior of PETG was studied by fusion index instrument, rotational rheometer,and torque rheomoeter. It was revealed that, the simultaneous addition of pyromellitic dianhydride(PMDA) and triglycidylisocyanurate(TGIC) to PETG led to higher melt strength and viscosity. In this case, the melt flow index of the extended PETG decreased from 12.83 to 7.50 g/10 min. While the zeroshearing viscosity (η0) increased from 2020 to 4760 Pa·s and the characteristic relaxationtime (τ0) increased from 0.78 to 3.58 s. Moreover, the extended PETG remained a linear structure and no gel was formed.

Key words: Poly (ethylene terephthalateco-1, 4-cylclohexylenedimethyleneterephthalate), chain-extension reaction, rheological properties, combining chain extending agents