Title of article :
Process analysis of phase transformation of α to β-form crystal of syndiotactic polystyrene investigated in supercritical CO2
Author/Authors :
Liao، نويسنده , , Xia and He، نويسنده , , Jiasong and Yu، نويسنده , , Jian، نويسنده ,
Issue Information :
دوهفته نامه با شماره پیاپی سال 2005
Abstract :
Mechanism of solid phase transformation of α to β form crystal of syndiotactic polystyrene (sPS) was investigated in supercritical CO2. The phase transformation occurred in the original pure α and mixed (α+β) form sPS in supercritical CO2 was traced as a function of temperature and pressure by means of wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC). At appropriate temperature and pressure, sPS underwent solid phase transitions from α to β form. Higher temperature or higher pressure favored this transformation. Compared to the original pure α form sample, the original β form crystal in the mixed (α+β) form sample acted as the nucleus of β form crystal, so that reduced the transition temperature and pressure.
Keywords :
Syndiotactic polystyrene , supercritical CO2 , Solid phase transition