Cosolvent effect of water in supercritical carbon dioxide facilitating induced crystallization of polycarbonate |
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| Authors: | Wentao Zhai Jian Yu Weiming Ma Jiasong He |
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| Affiliation: | 1. Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Engineering Plastics, Joint Laboratory of Polymer Science and Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China;2. Graduate School, Chinese Academy of Sciences, Beijing 100039, China;3. Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Engineering Plastics, Joint Laboratory of Polymer Science and Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, ChinaBeijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Engineering Plastics, Joint Laboratory of Polymer Science and Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China |
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| Abstract: | Water‐induced crystallization of polycarbonate (PC) was investigated in water‐saturated supercritical CO2 (scCO2) in the range of 80–160°C and 12–20 MPa, with the help of differential scanning calorimetry and wide‐angle X‐ray diffraction. Compared with pure scCO2, the enhanced plasticizing effect of water‐saturated scCO2 reduced the energy‐barrier for the motion of polymer chains, hence increased the crystallization rate of PC, and reduced the pressure threshold for crystallization from 14 to 12 MPa. On the other hand, the presence of water did not affect the thermodynamics of PC crystallization in scCO2. A 3D‐diagram was established to show the relationship between crystallization and solubility parameter of mixed supercritical fluid at different temperatures and pressures. The results show clearly that the PC has a wider range of crystallization temperature and pressure in water‐saturated scCO2 than in pure scCO2, mostly because the addition of water increased significantly the solubility parameter of mixed supercritical fluid, and decreased the difference in solubility parameter between PC and water‐saturated scCO2. POLYM. ENG. SCI., 47:1338–1343, 2007. © 2007 Society of Plastics Engineers |
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