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Supercritical CO 2 induced phase transition of Form III in isotactic poly‐1‐butene
Author(s) -
Li Lei,
Liu Tao,
Zhao Ling,
Yuan Weikang
Publication year - 2009
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.341
Subject(s) - differential scanning calorimetry , supercritical fluid , recrystallization (geology) , fourier transform infrared spectroscopy , tacticity , phase transition , amorphous solid , glass transition , materials science , infrared spectroscopy , crystal (programming language) , infrared , chemistry , analytical chemistry (journal) , crystallography , polymer chemistry , polymer , organic chemistry , chemical engineering , thermodynamics , polymerization , optics , paleontology , programming language , physics , computer science , engineering , biology
Abstract The effect of supercritical or high‐pressure CO 2 on the recrystallization of Form II in isotactic poly‐1‐butene (iPB‐1) during the melting of Form III was investigated using high‐pressure differential scanning calorimetry (DSC). The results showed that the recrystallization of Form II was inhibited by CO 2 . The crystal–crystal transition of Form III to I′ in ambient nitrogen and supercritical CO 2 was studied using fourier transform infrared spectroscopy (FTIR) and DSC. The results showed that CO 2 promoted the phase transition and the transition proportion of Form III increased with the CO 2 pressure increasing. Form III completely transformed into Form I′ at 18 MPa. Moreover, supercritical CO 2 could induce the amorphous region to transit into Form I′. The probable mechanism of the CO 2 effects on Form III multiple transitions was also proposed. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.