氯化1-羧甲基-3-甲基咪唑对PLA/POE-g-GMA共混物结构演化与性能的影响

Effect of 1-Carboxymethyl-3-Methylimidazolium Chloride on Evolution of Structure and Properties of PLA/POE-g-GMA Blends

通过熔融共混法制备了聚乳酸、甲基丙烯酸缩水甘油酯接枝乙烯-辛烯共聚物与氯化1-羧甲基-3-甲基咪唑离子液体的共混物(PLA/POE-g-GMA/ILs),并使用差示扫描量热仪(DSC)、热重分析仪(TG)、扫描电子显微镜(SEM)、电子万能试验机等研究了ILs对PLA/POE-g-GMA共混体系结构演化与性能的影响。TG结果及SEM图像表明ILs的引入可以明显改变PLA与POE-g-GMA的相互作用,当ILs添加量较低时,PLA共混体系出现明显的相分离,但当ILs添加量提高后,ILs可以催化PLA与POE-g-GMA的相界面反应,使共混体系形成微交联结构,材料的力学性能提高。DSC结果表明,ILs的引入可降低PLA的玻璃化转变温度,提高PLA的冷结晶能力,仅添加0.5%的ILs即可使共混体系中PLA的结晶度由17.5%提高至28.7%,表明ILs在促进相界面交联的同时明显提高PLA的链段运动能力;当ILs质量分数为2%时,共混材料的拉伸强度由30.2MPa提高至32.6MPa,断裂伸长率由44.8%提高至87.3%,刚韧平衡性良好。

The interface compatibilization process of polylactic acid(PLA)/POE-g-GMA blends during melt processing is an important scientific issue in PLA blending modification.In this study,the blends of polylactic acid/glycidyl methacrylate grafted ethylene-octene copolymer/chlorinated 1-carboxymethyl-3-methylimidazole ionic liquid(PLA/POE-g-GMA/ILs)were prepared by melt blending.The effect of ILs on the structure of PLA/POE-g-GMA systems were investigated by DSC,TGA and SEM.Meanwhile,the mechanical properties of PLA compounds were also investigated.The TG results and SEM images show that ILs could significantly change the interaction between PLA and POE-g-GMA.When the amount of ILs added is low,PLA blends show the characteristics of phase separation,but when the amount of ILs increases,a cross-linking reaction between PLA and POE-g-GMA occurs and the micro-crosslinks structure is formed inside the blends,hence the mechanical properties of the material are significantly improved.DSC results reveal that the introduction of ILs could reduce the Tg of PLA and increase the cold crystallize ability of PLA.Only 0.5%ILs could increase the crystallinity of PLA from 17.5%to 28.7%,which indicates that ILs could significantly enhance the segmental mobility of PLA while promoting the interface cross-linking reaction.When the mass fraction of ILs added reaches 2%,the tensile strength of the material is increased from 30.2 MPa to 32.6 MPa,the elongation at break is increased from 44.8%to 87.3%,exhibiting an excellent strength-toughness balance.