Polypropylene Surface Characteristics After Exposure To Hydrogen Peroxide and Heat Processing

Abstract

Polypropylene cups exposed to a range of aseptic packaging ster ilization conditions were examined for alterations in surface properties. The main mechanisms that affected the behavior of isotactic polypropylene contain ers in this sterilization system were the annealing of the inner layer due to heat and an increase in surface polarity possibly induced by both heat and peroxide oxidation. ATR-FTIR scans were not able to measure increases in the formation of carbonyls at a thickness of one micron. Contact angle measure ments which interact directly with the container surface did show significant surface differences. The container surface became more polar as the tempera ture increased or with exposure to hydrogen peroxide. Electron microscopy demonstrated that the polypropylene surface had been physically altered and the contour changed.