Shear-induced crystallization in poly (trimethylene terephthalate)

Abstract

In plastics processing, polymer melts are generally sheared (i.e., they undergo shear flow) which may or may not enhance crystallization rates depending on thefavored conformational state of polymer molecules in the crystals. Poly (trimethylene terephthalate) (PTT) is a new type of polyester that has recently been commercialized as a result of the low production cost. In this work, shear-induced from both the melt and the glassy states and in both isothermal and non-isothermal regimes using differential scanning calorimetry technique. In cold crystallization, shear-treated samples were prepared using cone-and-plate and capillary rheometers. The cold crystallization peak temperature for shear-treated samples was also shifted to lower temperatures. A modified differential Nakamura model, which takes into account the effect of shear, was used to analyze the data, A cone-and-plate rheometer was used to investigate the in situ shear-induced melt crystallization in PTT. A simplified model describing the effect of shear on the shift in the induction time was used to analyze the data.