聚乳酸/乙烯-醋酸乙烯酯共聚物共混物的形态与黏弹行为  

MORPHOLOGY AND VISCOELASTIC BEHAVIOR OF POLYLACTIDE/ETHYLENE-VINYL ACETATE COPOLYMER BLENDS

作　　者：张洁[1,2] 吴德峰[1,2] 周卫东 张明[1,2] 

机构地区：[1]扬州大学化学化工学院,扬州225002 [2]扬州大学江苏省环境工程与环境材料重点实验室,扬州225002 [3]扬州大学测试中心,扬州225002

出　　处：《高分子学报》2011年第2期139-144,共6页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号50803052);江苏省自然科学基金重点项目(项目号BK2010040);中国博士后基金(20080441078;200902532)资助

摘　　要：熔融共混制备了不同组分比的聚乳酸(PLA)/乙烯-醋酸乙烯酯共聚物(EVA)共混物,采用扫描电子显微镜(SEM)、溶剂选择性蚀刻和旋转流变仪研究了共混物不相容的相形态及其黏弹响应.研究结果表明,PLA/EVA共混物为典型的热力学不相容体系,两基体组分间的界面张力约为2.2 mN/m;因此随组分比的不同,共混物表现出"海-岛"分散和双连续的不相容相形态;体系中EVA的相反转浓度约为50 wt%～60 wt%,这与黏性模型对相反点预测的结果一致;与双连续相形态的体系相比,乳液模型能够更好的描述具有"海-岛"分散形态的体系的线性黏弹响应,共混体系相对较宽的相反转区域主要源于两组分间较大的弹性比以及EVA自身的屈服行为.Polylactide/ethylene vinyl acetate copolymer blends（PLA/EVA） with various blend ratios were prepared by melt mixing.The phase morphology and viscoelastic properties of the blends were then studied using scanning electron microscope（SEM）,selective etching and rheometer,respectively.The results show that the PLA/EVA blends are typical thermodynamically immiscible blends with interfacial tension values of about 2.2 mN/m between the two polymers.Hence the blend systems present ＂sea-island ＂ and co-continuous morphology at various blend ratios.The phase inversion content of EVA component is about 50 wt% ～ 60 wt%,which is in agreement with the results predicted by the viscous model.In contrast to that of the blend with co-continuous morphology,the linear viscoelastic response of the blend with＂sea-island＂morphology can be better described by the emulsion model.The relatively wide region of phase inversion of the PLA/EVA blend systems is mainly attributed to the rather high elasticity ratio between the two polymers and also to the yielding behavior of EVA.

关 键 词：聚乳酸 乙烯-醋酸乙烯酯共聚物 共混 形态 黏弹行为 

分 类 号：O631.3[理学—高分子化学]