THERMAL-ANALYSIS STUDIES USING OSCILLATION DSC TO DETERMINE CHANGES IN LD ETHENE BUTENE COPOLYMER INDUCED BY GAMMA-RADIATION TREATMENT

A polymeric material is used in one part of a container for an eye-dro p solution. The material is sterilized by ionizing radiation. The effe ct of exposure to different doses was studied by thermal analysis. The technique used is called oscillating DSC. The DSC signal can be separ ated into two components, reflecting reversible reactions and non-reve rsible reactions respectively. The sum of these two components makes u p the conventional DSC signal. The conventional DSC signal showed no v ariation in the enthalpy for a melting reaction. However, the two comp onents showed very clear changes, which could be correlated to dose. T he most significant changes were found in the non-reversible component during heating of the samples.