Rubber modification of polyester resins, 2. Impact behaviour and morphology

Brittle thermosetting polyester resins are blended with low molecular weight liquid polybutadiene rubbers. The morphology of the rubber modified resins was investigated as function of the nature of terminal groups of the polybutadiene, either hydroxyl or isocyanate and as function of composition. The concepts of the linear elastic fracture mechanism (LEFM) were applied to the prepared systems, to study their fracture behaviour. Interesting results were obtained when using a rubbery phase able to react with the base polyester leading to the formation of an A-B-A type block copolymer.