Properties And Utilization Of The Green Fiber Waste From Spinning

Polycarbosilane(PCS)is a precursor for the preparation of small diameter continuous SiC fibers.The preparation of continuous SiC fibers includes polycarbosilane synthesis,melt spinning,infusible treatment and pyrolysis.Melt spinning is an important step to determine the diameter and continuity of the fiber.Therefore,it is a key process step.During melt spinning,some green fibers are below the standard,and also some PCS leftover is produced.How to recover and reuse the residue is of great significance to reduce the production cost.In this study,the PCS was recovered by removing water and oil,dissolving it with xylene,filtering to remove impurities,distilling to remove xylene and finally producing PCS granules.The chemical structure well as the physical and chemical properties of the recovered PCS was systematically analyzed.The recovered PCS is spun and made into SiC fiber to test the PCS quality.The results show that after reasonable treatment,the main performance indicators of recovered PCS are the softening point of 190?230?,oxygen content of 0-0.8%,and the average number molecular weight of Mn=900-1400.These PCS has good properties of spinning,cross-linking and pyrolysis and are suitable for preparing small diameter continuous SiC fibers.