聚乳酸/改性聚醚酯嵌段共聚物共混体系的结构与性能

Structure and Properties of Poly( Lactic Acid) /Modified Poly( Ether-Ester) Block Copolymer Blends

采用熔融挤出共混的方法制备了聚乳酸(PLA)/改性聚醚酯嵌段共聚物(CH4132)共混物。利用差示扫描量热分析、动态力学热分析及场发射扫描电子显微镜等研究了共混物的结晶熔融行为、动态力学性能、相形态及力学性能。结果表明,CH4132的添加抑制了PLA的冷结晶能力,而对熔融及熔态结晶行为没有影响;PLA与CH4132具有部分的相容性且相容程度受CH4132含量影响;共混物呈现出以PLA为海、CH4132为岛的典型海岛结构;共混物的拉伸强度、弯曲强度和模量等刚性量随CH4132添加而降低,但体系的断裂伸长率和冲击强度等韧性性质得到了明显改善,在CH4132质量分数为10%时断裂伸长率最大,质量分数为30%时冲击强度为纯PLA的4.5倍。

Poly( lactic acid)( PLA) /modified poly( ether-ester) block copolymer( CH4132) blends were prepared by melt extrusion. The thermal properties,dynamic mechanical properties,morphologies and mechanical properties of blends were investigated by DSC,DMTA and SEM. The results show that the cold crystallization ability of blends is depressed with addition of modified poly( ether-ester) block copolymers( CH4132),but the melt points and melt crystallization behavior get almost no change with addition of CH4132. PLA and CH4132 are partly compatible and the CH4132content influences the compatibility between PLA and CH4132. The morphologies are typical 'sea-island'structure.Their tensile strength,modulus of elasticity,break strength,flexural strength and flexural modulus gradually reduce with addition of CH4132,but the elongation at break and Izod impact strength improve significantly with addition of CH4132.When the CH4132 content in blends is 10%,the elongation at break is the maximum. The Izod impact strength of blends with 30% CH4132 is 4. 5 times greater than that of pure PLA.