SUPERCRITICAL WATER AND LOWER ALCOHOLS AS SOLVENTS FOR HEAT-RESISTANT POLYMERS

摘要

The interaction of polymers, in particular heat- and thermoresistant polymers, with supercritical solvents such as water and lower alcohols has been investigated. Products (nano/microparticles or liquid solutions) that form at throttling of supercritical solutions have been studied. Polyphenylene sulfide (PPS), polypyromellitimide (PI), polytetrafluoroethylene (PTFE), polycarbonate (PC), polysulfone (PS), polyetherimide (PEI), polyethersulfone (PES), polyphenylsulfone (PPSF), and polyacetal (PA) were chosen as subjects of the study. Experiments were carried out in an autoclave reactor under stirring at temperature 375-380°C and pressure 240-260 atm for the system "polymer- SCW", and at 260-265°C and 100-190 atm for the system "polymer - sc-alcohol". Contact time was ca. 2 h for all the experiments. Then supercritical fluid was throttled to a low-pressure chamber onto specially designed targets. Structure of the products precipitated on the targets after throttling was analyzed by scanning electron microscopy (SEM). In all cases, the formation of solid micro- and nanoparticles of polymer or its destruction products was observed.