Mapping of Chemical Distribution and Semi-Quantitative Evaluation of Compatibility in Polypropylene Based on Confocal Raman

Raman mapping was employed to determine the spatial distribution of monomeric units in polypropylene at the micron scale. The instrument was calibrated using a series of ethylene/propylene copolymer samples containing various amounts of comonomer. The calibration model was developed using the Partial Least Squares (PLS) method and validated against NMR results. For the measurement, confocal raman mapping was conducted across the samples to measure the content of ethylene units. The results were demonstrated as heat maps of the ethylene content. It exhibi t ed the different of chemical distribution between a commercial heterophasic copolymer of propylene (HeCoPP) and a commercial random copolymer (RanCoPP). Furthermore, A semi-quantitative evaluation method for compatibility was developed by analyzing the frequency distribution of ethylene content.