聚左旋乳酸遥爪离聚物的静态结晶及剪切诱导结晶行为  

Static Crystallization and Shear Induced Crystallization of the Poly(L-lactic acid)Telechelic Ionomer

作　　者：刘凡 黄绍永[1] 陈全[1,2] LIU Fan;HUANG Shao-Yong;CHEN Quan(State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China;School of Applied Chemistry and Engineering,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学院长春应用化学研究所,高分子物理与化学国家重点实验室,长春130022 [2]中国科学技术大学应用化学与工程学院,合肥230026

出　　处：《应用化学》2023年第10期1412-1419,共8页Chinese Journal of Applied Chemistry

基　　金：国家自然科学基金(No.92161126)资助。

摘　　要：遥爪离聚物体系由于易形成相对均匀的可逆网络,受到高性能材料领域学者的广泛关注。通过引入磺酸根和Na+反离子,设计合成了一种分子链轻微缠结的聚左旋乳酸遥爪离聚物,由于离子聚集的“锚定”作用,其静态结晶动力学显著延迟。通过时温叠加得到的样品线性黏弹准主曲线显示出宽平台和末端松弛延迟的特点,这反映了强缔合的特点。在韦森堡数大于1的剪切流场作用下,该材料表现出剪切增稠和结晶加速行为。研究发现,增稠是剪切诱导结晶引起的,增稠可能发生在两个区域,即在剪切应力稳定之前或者之后,并且增稠发生在剪切应力稳定之后所需的临界功明显更高,这可能与稳定后缔合点连续的解离和再缔合导致的能量损耗相关。The telechelic ionomer tends to form a relatively uniform reversible network and has attracted the attention of many polymer researchers who are seeking high-performance materials.We synthesize the slightly entangled poly(L-lactic acid)telechelic ionomer based on sodium sulfonate groups.The telechelic samples exhibit extremely slow crystallization kinetics below the melting temperature(Tm)and above the glass transition temperature(Tg),which enables us to examine the linear viscoelasticity of the ionomer melt sample therein.The ionic aggregates form physical crosslinks,leading to a wide plateau regime and delayed terminal relaxation.The application of shear flow with Weissenberg number>1(at 85℃)strongly accelerates the crystallization,leading to the strong shear thickening behavior.The critical work(Wcrit)obtained in the case that the thickening occurs after achieving the steady state is higher than that in the opposite case,where the thickening occurs before achieving the steady state,suggesting that the continuous dissociation and association(during the steady state)dissipate a fraction of energy that does not contribute to the flow-induced crystallization.

关 键 词：聚左旋乳酸遥爪离聚物 剪切诱导结晶 流变学 

分 类 号：O631[理学—高分子化学]