Effect of supercritical carbon dioxide on the crystallization and melting behavior of linear bisphenol A polycarbonate

Journal of Polymer Science, Part B: Polymer Physics - Tập 42 Số 2 - Trang 280-285 - 2004
Xia Liao1, Jin Wang1, Gang Li1, Jiasong He1
1State Key Laboratory of Engineering Plastics, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Science, Beijing 100080, People's Republic of China

Tóm tắt

AbstractThe crystallization and melting behavior of bisphenol A polycarbonate treated with supercritical carbon dioxide (CO2) has been investigated with differential scanning calorimetry. Supercritical CO2 depresses the crystallization temperature (Tc) of polycarbonate (PC). The lower melting point of PC crystals increase nonlinearly with increasing treatment temperature. This indicates that the depression of Tc is not a constant at the same pressure. Tc decreases faster at a higher treatment temperature than at a lower temperature. The leveling off of the depression in Tc at higher pressures is due to the antiplasticization effect of the hydrostatic pressure of CO2. The melting curves of PC show two melting endotherms. The lower melting peak moves to a higher temperature with increasing treatment temperature, pressure, and time. The higher temperature peak moves toward a higher temperature as the treatment temperature is increased, whereas this peak is independent of the treatment pressure, time, and heating rate. The double melting peaks observed for PC can be attributed to the melting of crystals with different stability mechanisms. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 280–285, 2004

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Thông tin xuất bản

Journal of Polymer Science, Part B: Polymer Physics

Tập 42 Số 2

280-285

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