Polymer Engineering and Science, Vol.41, No.10, 1674-1682, 2001
Microstructural effects on hot drawing syndiotactic styrene p-methyl styrene copolymer
Crystalline syndiotactic styrene/p-methyl styrene copolymer (SPMS) has been oriented by tensile drawing at various temperatures between the glass transition and crystalline melting point. The microstructural changes resulting from drawing have been studied using differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). With increasing draw temperature, both melting temperature and crystalline dimensions of the oriented samples increase. The heat of fusion increases with increasing draw temperature up to similar to 200 degreesC. It also increases with draw ratio and draw rate, while the crystalline width increases only with draw ratio. The amorphous fraction shows a clear glass transition, the temperature of which (T-g) increases with draw ratio. However, T-g decreases somewhat with increasing draw temperature. This is interpreted in terms of the stretching of the randomly coiled amorphous phase molecules.