Carboxylation of linear low density polyethylene through gamma irradiation in presence of supercritical carbon dioxide. Grafted groups analysis via derivatization procedures

A linear low-density polyethylene was gamma irradiated in presence of carbon dioxide under supercritical conditions. As already reported, this process can be an interesting way to graft carboxylated functions to the polyethylene chains. In this work a detailed analytical investigation of the carboxylation products grafted on LLDPE are presented. Derivatization procedures with sulfur tetrafluoride and nitrogen monoxide, in order to selectively convert the carboxylated functions into groups more easily identified and quantified by FTIR, were performed. The chemical nature of the grafted groups is very similar to that obtained through gamma irradiation in air; furthermore, a significant degree of crosslinking is observed.