材料期刊网

为了得到刚性与韧性平衡的聚乳酸(PLA)基可生物降解共混材料,通过熔融共混挤出法制备了不同质量比的PLA/己二酸-对苯二甲酸-丁二酯共聚物(PBAT)/聚(3-羟基丁酸-co-羟基戊酸共聚酯(PHBV)可全生物降解共混材料,采用 SEM、TG、DSC、毛细管流变仪和万能材料试验机对 PLA/PBAT/PHBV共混材料的形态结构、热性能、流变性能和力学性能进行了研究。结果表明：PLA/PBAT/PHBV共混材料的热失重起始分解温度相对纯PHBV提高了45℃,热稳定性提高；共混体系中各组分的玻璃化转变温度与单一体系相比几乎无变化,PLA/PBAT/PHBV共混体系为完全不相容体系,同时 PBAT 和 PHBV 的加入阻碍了 PLA 的冷结晶；PLA/PBAT/PHBV 共混体系的共混形态呈“海-岛”分布,PBAT 和 PHBV 均匀地分散于 PLA 基体中,相界面分明；随着PBAT含量增加,PLA/PBAT/PHBV共混材料熔体的流动性增加,温度变化对黏度的影响变大；PLA/PBAT/PHBV质量比为70/20/10的共混材料可在保留纯PLA 60%拉伸应力的同时,拉伸应变提高到纯PLA的2.6倍,韧性得到改善。所得结论表明PLA/PBAT/PHBV质量比为70/20/10的共混材料的综合力学性能较纯PLA好。

In order to obtain poly(lactic acid)(PLA)matrix biodegradable blends whose stiffness is balanced with toughness,PLA/poly(butylenes adipate-co-terephthalate)(PBAT)/poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV)fully biodegradable blends with different mass ratios were prepared by melting co-extrusion method.The morphology structures,thermal characteristics,rheological behavior and mechanical properties of PLA/PBAT/PHBV blends were investigated with SEM,TG,DSC,capillary rheometer and universal material testing machine. The results show that the initial decomposition temperature of PLA/PBAT/PHBV blends increases by 45 ℃ com-pared with pure PHBV,and the thermal stability of PLA/PBAT/PHBV blends is enhanced.Glass transition tem-peratures of each component in the blend system change little compared with the unitary system,which indicates that the PLA/PBAT/PHBV blend system is a complete incompatible system.At the same time,the cold crystalliza-tion of PLA is confined by the incorporation of PBAT and PHBV.The blend morphology of PLA/PBAT/PHBV blend system presents as a“sea-island”distribution,PBAT and PHBV distribute in PLA matrix evenly,and the in-terfaces between different phases are clear.When the content of PBAT increasing,the rheological of PLA/PBAT/PHBV blends melt is improved,and the effect of temperature on viscosity increases.The tensile strain of PLA/PBAT/PHBV blends with PLA/PBAT/PHBV mass ratio of 70/20/10 improves to 2.6 times of that of pure PLA, the toughness has been improved,and in the meanwhile,60% tensile stress of pure PLA can be maintain.The con-clusions obtained show that the comprehensive mechanical properties of PLA/PBAT/PHBV blends with PLA/PBAT/PHBV mass ratio of 70/20/10 is better than that of pure PLA.