Effect of supercritical carbon dioxide on the crystallization behavior of poly(ether ether ketone)

Abstract

The supercritical CO2 (sc-CO2) provided a moderate condition to make the amorphous CO2/poly(ether ether ketone) (PEEK) mixtures at 30 MPa and 40°C. The crystal is obtained directly after treating CO2/PEEK mixture from 70 to 240°C. The crystallization behavior of CO2/PEEK mixtures before and after treatment is investigated in detail by using differential scanning calorimetry (DSC), dynamic mechanical analysis, and wide-angle X-ray diffraction. DSC curves of CO2/PEEK samples showed the double cold crystallization peaks. The lower cold crystallization peak moves to higher temperature with the content of CO 2 decreasing, and the higher cold crystallization peak keeps their temperatures at about 172°C without a remarkable change. The dynamic mechanical spectrometry was also introduced to explain the relaxation behavior of the glass transition and crystallization. © 2007 Wiley Periodicals, Inc.