FEATURES OF THE STRUCTURE OF NETWORKS IN POLYETHYLENE PHOTOCHEMICALLY CROSS-LINKED IN THE PRESENCE OF VARIOUS PHOTOINITIATORS

Photochemically crosslinked LDPE and linear PE films have been studied by gel-sol analysis, equilibrium swelling, measuring of elastic properties of swelled samples. Sulfur monochloride, sulfuryl chloride, xantone and 2-ethylanthraquinone have been used as photoinitiators. The behaviour of swelled films under loading corresponds to the phantom model of networks. The densities of chemical crosslinks in such networks have been calculated in the framework of this model. In films crosslinked with sulfur monochloride and sulfuryl chloride photoinitiators the values of crosslinks density determined from the equilibrium swelling, strain isotherms and gel-sol analysis coincide, while for xantone and 2-ethylanthraquinone photoinitiators these values are different. These and some other data point out the dependence of the crosslinks topology in PE on the photoinitiator nature.