Size-Frustrated Thickening Growth of Extended-Chain Crystals in a Poly (Ethylene Terephthalate)/Bisphenol A Polycarbonate Blend Under High Pressure

High-pressure crystallized blend samples of poly (ethylene terephthalate)/bisphenol A polycarbonate (PET/BAPC) were investigated with scanning electron microscopy (SEM), confocal laser micro-Raman spectroscopy, and a standard general area detector diffraction system (GADDS) X-ray micro-diffraction system. The results showed that long time annealing at high pressure could result in extended-chain polymer single crystals with thicker lamellae. However, the large size of such crystals was also found to frustrate their thickening growth along the c-axis thickness, as demonstrated by the observation of a novel wrinkled crystal. The winkled crystals with different morphologies were thought to be formed as the compromise between the kinetic pathway and the thermodynamic driving force during the size-frustrated thickening growth of the large polymer crystals. Further observations revealed that environmental confinement was the main factor responsible for the creation of the wrinkled structures in polymer extended-chain crystals. The present study may promote understanding of the fundamental nature of the crystal thickening in these binary polyester blends.