TheGlassTransitionIthaslongbeenknownthatamorphouspolymerscanexhibittwodistinctlydifferenttypesofmechanicalbehavior.Some,likepolymethylmethacrylate(Lucite,Plexiglas)andpolystyrene,arehard,rigid,glassyplasticsatroomtemperature,whileothers,forexample,polybut (共 10594 字) [阅读本文] >>