Crystallization and equilibrium melting behavior of PBT/PETG blends

The results of studies of equilibrium melting point and crystallization beh avior of PBT/PETG blends are reported for the first time. A single composit ion-dependent glass-transition temperature is observed in the DSC studies. The isothermal crystallization studies of the blends indicate I retardation in crystallization rate as evidenced by the increase in crystallization ha lf time. The retardation in crystallization rate has been attributed to the miscibility in the molten state :Ind the hindrance to the diffusion of cry stallizable units. This assumption is further supported by. the composition dependence of the crystallization half time. A composition-dependent melti ng point depression hai: been observed which haj been attributed tu the pos sible thermodynamic and morphological effects. The interaction parameter ca lculated by analyzing equilibrium melting point depression shows compositio n-dependent negative values confirming the miscibility of the systems. Thes e results are in good agreement with our earlier results on mechanical anti dynamic mechanical properties of PBT/PETG blends. (C) 1999 John Wiley & So n, Inc.