تهيه اسفنج پلي اتيلن داراي پيوندهاي عرضي با استفاده از تابش گاما

Preparation of Crosslinked Polyethylene Foam by Using Gamma Ray

In this paper, the production of polyethylene foam crosslinked by gamm irradiation is reported. At first the behavior of polyethylene against gamma irradiation was studied. Gel-content experiments were performed to investigate the efficiency of two crosslinked promoters, DCP and TMPTA. The results showed that these additives had significant effect in increasing the gel percent at low doses. But their effect was diminished at higher doses. The next phase was to determine the optimum dose and level of crosslinking promoters. To do this, rheometry experiments were per-formed on both crosslinked and virgin polyethylene and also the states of foaming of polyethylene in different gel percents were compared together. In the next stage, compression moulding technique was selected after examining different alternatives such as direct heating in oven or extrusion. Mould temperature and residence time of sample, were determined based on the results of DSC and TGA thermographs. The results showed that increase in blowing agent from 10 to 15 phr leads to cell rupture and an increase in density and thermal conductivity. Therefore, the concentration of 10 phr of blowing agent was reported as the optimum content in which the product had minimum density and thermal conductivity. The SEM micrographs confirmed previous results. Other experiments such as tensile strength and water absorption were also performed on samples and acceptable results proved the quality of the produced foams.