Syntheticfiberscanbeproducedfromawidevarietyofsubstances:polyesters,polyamides,vinyls,etc.Thesamematerialcanoftenbeusedinmoldingaswellasspinningprocesses.Someofthepolymers,especiallythosewhicharesuitablethermoplastics,arelargelyofpetroleumorigin;others,su (共 10478 字) [阅读本文] >>