共聚单元与拉伸外场对丁烯共聚物相转变的影响  

Influences of Co-Unit and Stretching on Phase Transition in Polybutene Random Copolymers

作　　者：郑力荣 李薇 马哲 盛京[1] Lirong Zheng;Wei Li;Zhe Ma;Jing Sheng(School of Material Science and Engineering,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学材料科学与工程学院,天津300350

出　　处：《高分子材料科学与工程》2021年第1期32-36,共5页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(51573132)。

摘　　要：利用广角X射线衍射方法原位研究了丁烯/4,4-二甲基-1-戊烯无规共聚物的静态和拉伸诱导相转变行为,发现4,4-二甲基-1-戊烯共聚单元可显著减慢聚丁烯form II向form I的静态转变速度,摩尔分数3.43%及以上插入率则可抑制拉伸诱导晶型转变。恒速率拉伸实验结果表明,拉伸应力主导转变动力学。在恒应力作用下,低插入率共聚物中form I含量在经历平台期后快速增加,而循环拉伸结果则进一步说明,应力松弛及重新加载过程中相转变依然遵循应力控制机理。The phase transition behaviors of butene/4,4-dimethyl-1-pentene random copolymers with different contents of co-units were studied combining in-situ wide angle X-ray diffraction with tensile test.The results show that the introduction of 4,4-dimethyl-1-pentene(44D1P)co-units can effectively retard the phase transition from form II to form I,where the 44D1P co-units of 3.43%can even completely suppress the stretching-induced phase transition.For the copolymers with no more than 0.75%44D1P co-units,stretching can not only accelerate the phase transition but also induce the complete transition of initial form II to form I,of which the transition kinetics is found dominated by the component stress perpendicular to the c-axis.Under the constant true stress of 9 MPa,the stretching-induced phase transition needs an induction period.The results obtained with the cyclic stretching show that the unloading and reloading of cyclic stretching do not influence the stress dependence of phase transition kinetics.

关 键 词：丁烯/4 4-二甲基-1-戊烯共聚物 相转变 拉伸场 广角X射线衍射 

分 类 号：O632.1[理学—高分子化学]