摘要:
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。
关键词:
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聚乳酸
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共聚物
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可生物降解
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形态结构
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性能
Abstract:
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 ℃ compared with pure PHBV, and the thermal stability of PLA/PBAT/PHBV blends is enhanced. Glass transition temperatures 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 crystallization 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 interfaces 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 conclusions 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.
百度学术
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