Dipak Sinha
When polymeric materials like Polyallyl diglycol carbonate (PADC), Polycarbonate (PC), Polyvinyl Chloride (PVC), Polypropylene (PP) etc. are exposed to gamma radiation, they show pronounced changes in their physical and chemical properties. Interestingly, the changes due to irradiation are varied in nature, proving that all polymers do not undergo similar type of modifications under similar irradiation conditions. Thus, while polymers like PADC and PVC do not reveal any change in the IR spectral pattern, the IR spectrum of polypropylene polymer confirms the total destruction of isotactic arrangements of the polymer leading to the formation of alcoholic and ketonic groups. The etch-rates are drastically enhanced due to irradiation at the highest dose for all types of PADC detectors which is not the case for polycarbonates. For polyacetate polymer, elimination of carbon dioxide takes place due to destruction of the ester group. Interestingly, in polycarbonate polymer it was observed that at the dose of 106Gy, phenolic groups form due to cleavage of ester bonds. Thermal stability of PADC (American-Acrylics) is drastically reduced at the doss of 106 Gy, whereas for polypropylene polymer, the stability is greatly enhanced. It is also observed that due to etching, thermal stability of PADC detectors decreases. Dielectric studies reflect the fact that at a gamma dose of higher than 104 Gy, PADC detector may not behave as an ideal nuclear track detector. This paper accounts the modifications on different types of polymeric track detectors due to gamma irradiation. Variations in different properties such as track properties, structural modifications, thermal properties, electrical properties etc. through a dose range of 101 Gy to 106 Gy are discussed
