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Cosolvent effect of water in supercritical carbon dioxide facilitating induced crystallization of polycarbonate
Author(s) -
Zhai Wentao,
Yu Jian,
Ma Weiming,
He Jiasong
Publication year - 2007
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20816
Subject(s) - supercritical fluid , crystallization , materials science , solubility , differential scanning calorimetry , polycarbonate , supercritical carbon dioxide , chemical engineering , amorphous solid , hildebrand solubility parameter , polymer , thermodynamics , organic chemistry , composite material , chemistry , physics , engineering
Water‐induced crystallization of polycarbonate (PC) was investigated in water‐saturated supercritical CO 2 (scCO 2 ) 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 scCO 2 , the enhanced plasticizing effect of water‐saturated scCO 2 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 scCO 2 . 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 scCO 2 than in pure scCO 2 , 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 scCO 2 . POLYM. ENG. SCI., 47:1338–1343, 2007. © 2007 Society of Plastics Engineers