Thermally recoverable crosslinked polyethylene

The thermal recovery of the stored stress in crosslinked polyethylene has been commercially exploited in the preparation of heat shrinkable materials. The study on thermally recoverable crosslinked polyethylene compositions is reported in this paper. Thermally recoverable compositions were prepared by cross-linking of four grades of polyethylenes in air using γ-rays from a Co-60 source. The effect of the irradiation dose on the gel fraction and radiation dose to gelation is studied. The effect of the melt index (MI) and the density of the polyethylene on the gel fraction, radiation dose to gelation, and recovery percentage of the stored stress is also studied. It is observed that the gel fraction is higher in case of the lower MI material and that rate of recovery is higher at higher temperatures. The rate of recovery of the stored stress is higher in case of the 100 kGy irradiated sample.