乙酰柠檬酸三正丁酯增塑改性淀粉/聚乳酸共混材料的结构与性能

Structure and Properties of Starch/Poly(Lactic Acid) Blends Plasticized by Acetyl Tributyl Citrate

以乙酰柠檬酸三正丁酯(ATBC)作为增塑剂,采用熔融共混法制备了淀粉/聚乳酸(PLA)共混材料。采用红外吸收光谱、扫描电镜、X射线衍射、热重分析及力学性能测试方法研究了ATBC对淀粉/PLA共混材料结构和性能的影响。结果表明,ATBC能与PLA和淀粉分子发生强相互作用,破坏淀粉/PLA共混物中原有的氢键,降低淀粉/PLA共混物的结晶度;在淀粉/PLA共混物中加入ATBC可提高PLA与淀粉的界面结合力,改善其相容性,进而改变淀粉/PLA共混材料的结构与性能。ATBC不影响共混材料的热稳定性,但能降低淀粉/PLA共混物的玻璃化转变温度(Tg)和熔点(Tm),改善加工性能;ATBC能显著提高淀粉/PLA共混材料的柔韧性,含20%ATBC的淀粉/PLA共混材料的断裂伸长率可达到365%。

Starch/poly( lactic acid)( PLA) blends plasticized with acetyl tributyl citrate( ATBC) were prepared by melt blending. Infrared absorption spectroscopy( IR), scanning electron microscopy( SEM), X-ray diffraction( XRD),thermal gravimetric analysis( TGA) and mechanical test were adopted to study the effects of ATBC on the structure and performance of starch/PLA blends. The results show that ATBC can form strong interactions between PLA and starch molecules,thus disrupting the inter and intra chain hydrogen bonding of starch and PLA chains and reducing the crystallinity of blends; compared with crude starch/PLA blend,the interfacial bonding strength between starch and PLA is improved,which is suggested by the better compatibility in ATBC plasticized blends. The glass transition temperature( Tg) and melting point( Tm) of starch/PLA blends decline with addition of ATBC,showing improved processing properties; meanwhile,the thermal stability of the blends could not be affected by ATBC; ATBC can significantly improve the flexibility of starch/PLA blends,and the elongation of starch/PLA blends containing 20% ATBC can reach365%.