Lesson 25　Synthetic Fibers(1)

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