Phase behavior of supercritical CO2/styrene/poly(ethylene terephthlate) (PET) system and preparation of polystyrene/PET composites

Phase behavior of supercritical CO2/stytene/poly (ethylene terephthlate) (P ET) system was determined at 35 degreesC and different pressures. The conce ntration of styrene in the fluid phase ranged from 0 to 1.3 mol/l. Styrene partitioned between the fluid phase and PET films, and significant amount o f styrene was absorbed into PET matrix. When the styrene contained 0.3 mol% initiator azobis (isobutyronitrile) (AIBN), the mass uptake was higher tha n that of the styrene without the initiator because the AIBN initiated poly merization during the soaking period. It was found that considerable amount of styrene was carried out by CO2 in the depressurization process. After t he depressurization process, the PET films impregnated with styrene and AIB N were placed in a reactor and heated at 80 degreesC for 4 h under the prot ection of N-2. and the PET/Polystyrene (PS) blends were obtained. The prope rties of the blends could be controlled by manipulating experimental condit ions, such as soaking time, pressure and styrene concentration. The blends were characterized using IR, SEM, rheological measurement, and some mechani cal properties were also determined. Rheometer study indicates that the pre sence of PS in PET can improve the mobility of PET. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.