In-situ spectroscopy of polymers processed with supercritical carbon dioxide

Supercritical CO2 can induce crystallization of amorphous polymers. Molecular level insight into the microstructures of CO2-processed polymers is needed to form a basis for utilization and optimization of supercritical fluid processing of polymeric materials. Spectroscopy is an economic tool to probe interactions at a molecular level. This understanding will help engineers to utilize molecular level information for improving macroscopic properties of polymeric materials by supercritical fluid processing. FT-IR spectroscopy has been applied to elucidate the morphology and microstructure of polymers processed with supercritical CO2. FTIR spectra of syndiotactic polystyrene show an increased degree of crystallinity after being subjected to scCO2. The various crystalline forms induced by CO2 in syndiotactic polystyrene were characterized via FTIR spectra. FTIR spectroscopy has been also used to measure the kinetics of CO2-induced crystallization in these polymers.