聚降冰片烯/聚乳酸共混物形状记忆效应的研究  

Studies on Shape Memory Effect of Polynorbornene/Poly(lactic acid) Blends

作　　者：肖雅 曲明[1] 史新妍[1] 

机构地区：[1]青岛科技大学高分子科学与工程学院橡塑材料与工程教育部重点实验室,青岛266042

出　　处：《高分子学报》2018年第3期402-409,共8页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号51273101);山东省高校科技计划(项目号J12LA14)资助项目

摘　　要：将聚降冰片烯(PNB)和聚乳酸(PLA)按照PNB/PLA(80/20)、(70/30)、(60/40)、(50/50)4种不同质量配比进行共混,采用X射线衍射(XRD)、动态力学分析(DMA)、示差扫描量热分析(DSC)等对共混物基本性能进行表征,同时采用DMA-Q800对其形状记忆效应进行探究.结果显示:4种共混物均有明显屈服现象,随着PLA含量的增加,屈服现象越明显;PNB/PLA共混物出现2个玻璃化转变温度(T_g),且不随共混物配比变化而变化;4种共混物均在2θ=18.45o附近出现特征衍射峰,且其结晶度随PNB含量的减少而降低;随PNB含量的增多4种共混物的形状记忆性能提高.对于PNB/PLA(80/20),在双重形状记忆中,其形状固定率为99.88%,形状恢复率为81.04%;在三重形状记忆中,总固定率和恢复率分别为98.83%和94.26%.Temperature responsive shape memory polymers（SMPs） find important applications in automotive, military, biomedical and other fields. In particular, SMPs responsive to human body temperature are highly desired for biomedical applications. Polynorbornene（PNB） has a Tg around human body temperature, exhibiting excellent shape memory properties, whereas poly（lactic acid）（PLA） has attracted great interest in biomedical fields due to its nontoxic and bioresorbable characteristics. Therefore, it is of great significance to explore the possibility of combining advantages of PNB and PLA. In this work, a simple blending strategy was adopted at varying weight ratios, and the shape memory, thermal and mechanical properties of the resultant blends were studied. The results showed that PLA promoted blend yield, and crystallization of PNB favored shape fixation and shape recovery. For PNB/PLA = 80/20 blend, the shape fixation rate was 99.88% and the shape recovery rate was 81.04% with the average shape recovery rate of 1.2%/min in the double shape memory. The total shape fixation rate and shape recovery rate were 98.83% and 94.26%, respectively, in the triple shape memory. In PNB/PLA blends, there was a certain interaction between the molecules, which limited, to a certain extent, the movement of the two polymer chains and reduced the crystallization of PLA. When the temperature was over 100 oC, cold crystallization of PLA appeared in the blends, and this cold crystallization degree increased with decreased PNB. With increased PNB content, PNB/PLA blend became more ductile, the elongation at break increased from a few percent to more than 200%, and the forced elastic deformation occurred, which were favorable for the shape fixation. In the blends, the super-macromolecular chains of PNB were intertwined, resulting in a large number of entanglement points, namely, physical cross-linking points in the materials, which could make the polymer chain movement seriously blocked and their wide range of slippage hampered,

关 键 词：聚降冰片烯 聚乳酸 形状记忆 应力松弛 结晶 

分 类 号：TQ317[化学工程—高聚物工业]