Preparation And Performance Research Of Biodegradable PBST/PLLA Elastic Fiber

Elastic fibers have the characteristics of low modulus,high elongation,and high resilience,so it has broad application prospect.However,existing elastic fibers are mostly non-degradable.To implement the "dual carbon" strategy and meet the sustainable development of chemical fiber,it is imperative to develop new biodegradable elastic fibers.In this thesis,the PBST/PLLA side-by-side elastic fibers were produced by using biodegradable poly(L-lactic acid)(PLLA)and poly(butylene succinate-co-terephthalate)(PBST)via regulating the content and distribution of the "soft" and "hard" segments in PBST molecular chains and combining the brittleness of PLLA and the toughness of PBST.The mechanism of elasticity and degradation properties were investigated.Firstly,the thermal,crystallization and rheology properties of PBST and PLLA were investigated.The results showed that: with the increase of the content of pure terephthalic acid(PTA),the melting point,thermal enthalpy and crystallization of PBST decreased first and then increased,when the PTA content is 30 mol%,reaching the minimum values;when PTA content are 45 mol% and 60 mol% PBST have relatively smaller apparent viscosity difference with PLLA at the same temperature and shear rate,which is more favorable for the preparation of PBST/PLLA side-by-side composite fibers.PBST/PLLA composite fibers were prepared by melt spinning with the mass ratio of PBST/PLLA=50/50,and were labeled as PBST-45/PLLA and PBST-60/PLLA by PTA contents.The results showed that: with same PTA content,heat-setting temperatures and drawn ratio are the key factors affecting the elasticity.At the drawing ratio of 1.25 times,PBST-45/PLLA shows the maximum elastic recovery rate of 90.8%;when the drawing ratio in1.4～1.5 times,PBST-60/PLLA shows the maximum elastic recovery rate of 96.2%～96.3%.PBST-45/PLLA showed better degradation performance than that of PBST-60/PLLA,and the PLLA was easier to degrade than the PBST.In summary,PBST/PLLA composite elastic fiber has excellent elasticity and degradability,so it has broad application prospect.