Preparation And Properties Of Polylactic Acid/Polyamide Elastomer Blended Fibers

As a biodegradable polymer material,polylactic acid(PLA)usually uses corn,wheat,etc.as raw materials.It is rich in source and environmentally friendly.It can be used as a substitute for petroleum-based materials and has good development prospects.However,the inherent brittleness and slow crystallization rate of PLA limit its application.Therefore,this paper uses melt blending to blend polyamide elastomers(PAE elastomers)with PLA with different dextro-lactic acid(D-LA)content to toughen PLA.At the same time,in order to further enhance the consistency of the blending system,polyvinyl acetate(PVAc)was used as a compatibilizer,melt blended with PAE elastomer and PLA and then spun.The structure and performance of the PLA/PAE/PVAc blend system was explored.The main contents and results of this paper are as follows:(1)The PLA and PAE elastomer were blended by melt blending to prepare PLA/PAE blends with different PAE elastomer content.Two PLAs with different D-LA content were selected,and the models were LX175(D-LA content less than 4%)and 2500HP(D-LA content 0.25%).The results show that after blending 2500HP with smaller D-LA content with PAE elastomer,the particle size of the dispersed phase of PAE elastomer is larger.With the increase of PAE elastomer content,the melting points of LX175/PAE blend and 2500HP/PAE blend change little,and the glass transition temperature(T_g)deflected to lower temperature indicates that PLA and PAE are partially compatible systems.In addition,the storage modulus(G’)of the blend is always greater than that of pure PLA,that is,PAE elastomer can effectively toughen PLA.After adding PAE elastomer,the tensile strength of the blend decreases,but the elongation at break increases.When the PAE content is 5%,the comprehensive mechanical properties of the LX175/PAE blend reach the best and when the PAE content is 10%,the comprehensive mechanical properties of the 2500HP/PAE blend reach the best.(2)PLA/PAE blended fibers with different PAE elastomer content were prepared by melt spinning.The results show that when the content of PAE elastomer increases,the crystallinity of the PLA component in the blended fibers increases,and there is an interaction between the two phases of the LA blend,but without new crystal form is found.The breaking strength,breaking elongation and tensile breaking specific work of the first-stage drafted blended fibers all increase first and then decrease.When the PAE elastomer content is 15%,the mechanical properties of the secondary draft blended fiber are the best.Its breaking strength is 487.7 MPa,higher than that of pure PLA about 51.4%,and the breaking elongation and the tensile breaking specific work are increased by 22.6%and 66.1%,respectively.(3)Using PVAc as compatibilizer,PLA/PAE/PVAc blended chips and blended fibers were fabricated via melt blending and melt spinning.The results show that after adding PVAc,the particle size of dispersed phase is reduced,the two-phase interface is blurred,the compatibility is improved,and the spinnability is significantly improved.The T_g of PLA/PAE/PVAc blends shifts to low temperature,which is a partially compatible system.When the PAE elastomer content is 20%,the breaking elongation of the blend comes up to61.1%,which is approximately 11 times that of pure PLA.In addition,when the PAE elastomer content is 10%,the comprehensive mechanical properties of the two-stage draft blended fibers are the superlative,with the breaking strength at 412.7 MPa,the breaking elongation and the breaking specific work are increased by 26.0%and 44.2%,respectively.