高剪切速率对PCL/RGO附生结晶行为影响的原位研究  

In⁃situ Study of the Epitaxial Crystallization of PCL/RGO at High Shear Rate

作　　者：苗伟俊 吴锋 王勇 王宗宝 MIAO Weijun;WU Feng;WANG Yong;WANG Zongbao(Ningbo Key Laboratory of Specialty Polymers,School of Materials Science and Chemical Engineering,Ningbo University,Ningbo 315211,China)

机构地区：[1]宁波大学材料科学与化学工程学院,宁波市特种高分子材料制备与应用技术重点实验室,宁波315211

出　　处：《高等学校化学学报》2021年第3期910-918,共9页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:52003127,U1532114);浙江省自然科学基金(批准号:LQ20E030006)资助。

摘　　要：以聚己内酯(PCL)/还原氧化石墨烯(RGO)复合材料为研究对象,利用同步辐射小角X射线散射(SAXS)和广角X射线衍射(WAXD)原位分析了75 s^(‒1)的高速率剪切作用前后的附生晶体结构演变及其对本体晶体形成的影响.研究结果表明,在剪切后降温160 s后,PCL分子链开始在RGO表面附生,形成表面结晶层,同时形成部分PCL本体晶体;在200~480 s的等温结晶阶段,大量PCL本体片晶生成并形成规整的周期结构.较高的剪切速率使体系的黏度降低,因此在较高的剪切温度下PCL分子链更容易由伸直链转变为无规线团,不利于PCL分子链在RGO表面形成表面结晶层.在剪切速率为75 s^(‒1)时,70℃的剪切温度更有利于PCL分子链在RGO表面附生形成表面结晶层.Polycaprolactone(PCL)/reduced graphene oxide(RGO)composites were used as the research object to study the evolution of the epitaxial crystalline structure and the influence on the formation of bulk crystal at the shear rate of 75 s^(‒1) by in⁃situ small-angle X-ray scattering(SAXS)and wide-angle X-ray diffrac⁃tion(WAXD)in this paper.The experimental results show that PCL molecular chains start to form epitaxial crystal layer on the RGO surface at 160 s after shear,and part of PCL bulk crystal is formed simultaneously.In the isothermal crystallization stage(200―480 s after shear),a large number of PCL bulk crystals are formed,which promotes the formation of regular periodic structure.The PCL molecular chain is more likely to change from the extensional chain to the random coil at a higher shear temperature because of the reduced viscosity at 75 s^(‒1),which is not beneficial for PCL molecular chain to form surface crystal layer on RGO.The shear temperature of 70℃is more favorable for the formation of PCL epitaxial crystal layer on the RGO at shear rate of 75 s^(‒1).

关 键 词：聚己内酯 还原氧化石墨烯 附生结晶 高速率剪切场 

分 类 号：O631[理学—高分子化学]