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pp because the homopolymer pp temperature is higher than 0c, very brittle, so many commercial pp materials are 1~4% ethylene random copolymer/higher proportion of ethylene content of the segment copolymer. copolymer type pp material has lower thermal distortion temperature (100c), low transparency, low gloss&low rigidity, but has stronger impact strength. the strength of pp increases with the increase of ethylene content.