Fire Safety Science Digital Archive

The method of modification of high pressure polyethylene including secondary polyethylene using phosphorus containing epoxy resin and polyvinyl alcohol is proposed. Conditions of the phosphorylation of epoxy resin and polyvinyl alcohol by anhydrides of methylphosphonic acid and/or by the methylphosphonic acid are determined. Reactive olygomeric and polymeric phosphorus containing components which can form crosslinked structures and/or interact with the functional group of a polymeric matrix, for example, in a secondary polyethylene are obtained. While reproducing a polymeric composition the competitional process of migration of fire retardant phosphorus containing systems (P-FRS) and the processes of the formation of crosslinked structures are observed. The formation of a crosslinked structure is possible into P-FRS as well as at the interaction of the FRS with active functional groups of the secondary polyethylene on the boundary of phases. The complex FRS which contains phosphorylated epoxy resin and red phosphorus is decomposed during reproducing of a modified polyethylene composition. In this case the phosphorylated epoxy resin diffuses with the formation of a crosslinked structure into a warm surface layer, and the red phosphorus is distributed into the polymeric matrix with a sufficient uniformity. During the destruction of phosphorylated polyvinyl alcohol the formation of polyenic structures and condensed polyphosphates or polyphosphonic acid takes place. These processes promote the carbonization and the decreasing of flammability. Therefore the FRS on the basis of phosphorylated polyvinyl alcohol is more effcctive than the system based on the phosphorylated epoxy resin. Modified polyethylenes (high pressure and secondary) can be classified as fire resistant materials according to the test results.