ADR4370F对聚乳酸流变行为和力学性能的影响

摘要

以环氧类扩链剂(ADR4370F)经双螺杆挤出机对聚乳酸(PLA)进行熔融扩链,并对其流变行为和力学性能进行了分析.结果表明,ADR4370F能有效提高PLA体系的储能模量、损耗模量、复数黏度、松弛时间(τ)和松弛模量H(τ);ADR4370F的加入使得材料弹性响应加快,黏性耗散减小,并当ADR4370F含量高于1.0%(质量分数,下同)时,体系出现"类凝胶"行为;Cole-Cole图揭示了PLA扩链体系出现支化结构,并通过vGP图预测其支化产物具有星形的拓扑结构;ADR4370F的加入有利于提高PLA的缺口冲击强度,而对拉伸强度则无明显影响.当其含量为1.0%时,材料的缺口冲击强度从3.62 kJ/m2提高到6.0 kJ/m2,比纯PLA提高了65.75%.%Ploy(lactic acid)(PLA)was chain-extended by an epoxy chain extender (ADR4370F) through melt extrusion, and then its rheological behavior and mechanical properties were investigated.The rheological evaluation indicated that the storage modulus, loss modulus, complex viscosity,relaxation time,and relaxation modulus of PLA were improved due to the chain extension by ADR4370F.Moreover,the elastic response became faster with the addition of ADR4370F but viscous dissipation became weaker.PLA exhibited a gel-like behavior when 1.0 wt%of ADR4370F was incorporated.Cole-Cole plots exhibited a branched structure formed by chain extension,and meanwhile vGP plots further predicted a star-like topological structure within the chain-extended PLA.The mechanical tests showed that the notched impact strength of PLA were improved with the addition of ADR4370F,and however there was almost little effect on tensile strength.With the addition of 1.0 wt % ADR4370F,the notched impact strength of PLA was improved to 6.0 kJ/m2 ,presenting an increase by 65.75 %compared with that of pristine PLA.