长碳链PA1212弹性体在热环境中的分子运动和氢键研究  

Molecular motion and hydrogen bond of long-chain PA1212 elastomer under thermal field

作　　者：蒋杰 唐秋雨 赵玲[1,2] 奚桢浩 袁渭康[1] JIANG Jie;TANG Qiuyu;ZHAO Ling;XI Zhenhao;YUAN Weikang(State Key Laboratory of Chemical Engineering,School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China;College of Chemistry and Chemical Engineering,Xinjiang University,Urumqi 830046,Xinjiang,China)

机构地区：[1]华东理工大学化工学院,化学工程联合国家重点实验室,上海200237 [2]新疆大学化学化工学院,新疆乌鲁木齐830046

出　　处：《化工学报》2022年第1期425-433,共9页CIESC Journal

基　　金：国家自然科学基金项目(21978089,21878256);中央高校基本科研业务费专项资金项目(22221818010);111计划项目(B20031);上海市优秀学科带头人计划项目(21XD1433000)。

摘　　要：热塑性聚酰胺弹性体因其优异的回弹性和二氧化碳选择透过性而受到广泛关注,而材料内氢键作用对弹性体相分离行为和力学性能有决定性影响。基于PA1212聚醚型弹性体,即PA1212为硬段,聚丙二醇-聚乙二醇-聚丙二醇三嵌段共聚醚为软段,通过原位红外光谱(FT-IR)、二维相关红外光谱(2D FT-IR)、原位广角X射线衍射(WAXD)分析,结合分子动力学模拟,研究了PA1212弹性体分子链运动行为和氢键解离方式。弹性体受热导致分子链运动能力增强,体系中氢键作用减弱,有序氢键(ordered hydrogen bond)向无序氢键(disordered hydrogen bond)转变,其中软段C-O-C和N-H形成的氢键优先解离,而硬段微区PA1212中C===O和N-H形成的氢键解离滞后;相比形成氢键的分子链间距d_(100),氢键面间距d_(010/110)受热变化更敏感,最终分子链间距和氢键面间距近似相等,即发生Brill转变,WAXD结果表明,加热促进了氢键的解离。分子动力学模拟结果验证了红外分析结果,氢键键长增加,氢键作用减弱,PA1212微区的氢键密度和强度总是大于聚醚微区,聚醚微区的氢键密度受加热影响下降更快。Thermoplastic polyamide elastomers(TPAEs)have attracted extensive attention in both academia and industry due to their excellent resilience and carbon dioxide permeability.Hydrogen bond has significant influence on the phase-separated structure and mechanical properties of polyamide elastomers.In this work,a TPAE comprised of long-chain PA1212 and poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol)was used to investigate its molecular motion and hydrogen bond during heating process by in situ FT-IR,2D correlation FT IR,in situ WAXD and molecular dynamic simulation.Upon heating,the mobility of the molecular chain is enhanced and the hydrogen bond of the system is weakened.The hydrogen bond between C-O-C and N-H dissociates prior to that of PA1212,whose ordered hydrogen bond transits to disordered hydrogen bond.The in situ WAXD results show that d_(100) is more sensitive to heat than d_(010/110) and that these two lattice distances are equal finally,where the Brill transition occurs.The WAXD results suggest that the dissociation of the hydrogen bond is promoted by heating.Molecular dynamic simulation verified the results by FT-IR.The simulation results show that hydrogen bond decreases with the increasing of its bond length during heating and that the density of hydrogen bond in the PA1212 domain is higher than that in polyether.The hydrogen bond of polyether chains reduces before that of PA1212.

关 键 词：长碳链聚酰胺弹性体 红外光谱 原位WAXD 分子模拟 氢键 

分 类 号：TQ323.6[化学工程—合成树脂塑料工业]