Effect of γ-irradiation on the molecular-topological structure of the polyethylene matrix of glass-reinforced plastic

The molecular-topological structure of polyethylene (PE) and a PE matrix in a glass-reinforced plastic (GRP) after γ-irradiation of the plastic was studied by means of thermomechanical spectroscopy. The four-block topological structure of unirradiated PE (one amorphous block and three crystalline phases with different initial melting temperatures) is transformed into a three-block structure in the GRP already at a minimal radiation dose of 25 kGy. The intermediate crystalline phase disappears under these conditions, the molecular relaxation characteristics in all topological blocks alter, and chemical branching points appear in the pseudonetwork structure of the amorphous matrix block.