残留溶剂在PMMA-CA聚合物膜中迁移及影响的多尺度分析  

Multiscale Analysis of the Migration and Influence of the Residual Solvent in Methyl Methacrylate-Acrylamide Calixarene Polymer Film

作　　者：刘满华[1] 陈维霞[1] 黄民[1] 

机构地区：[1]同济大学化学系,上海200092

出　　处：《高校化学工程学报》2013年第2期210-216,共7页Journal of Chemical Engineering of Chinese Universities

摘　　要：杂质对功能高分子聚合物理化性质的影响具有重要的学术价值与应用意义。今分别通过分子动力学(Molecular Dynamics,MD)及密度泛函(Density Functional Theory,DFT)等方法探索了聚合物玻璃态和橡胶态下溶剂扩散系数的不同以及残留溶剂对聚合物分子解离能的影响。根据自由体积理论,对聚甲基丙烯酸甲酯-丙烯酰胺杯芳烃(PMMA-CA)的玻璃化温度进行了分子动力学(MD)模拟,得到的自由体积与温度的关系曲线显示其玻璃化温度为395K。考察了玻璃态和橡胶态下溶剂扩散系数的不同,MD模拟得到的均方位移(Mean Square Displacement,MSD)曲线显示,聚合物在玻璃态下溶剂的自扩散系数远低于橡胶态下。通过密度泛函方法计算残留溶剂分子对杯芳烃解离能的影响,结果表明膜制备过程中残留的溶剂分子有利于杯芳烃的解离,但其影响比MMA分子共聚要弱得多。Studies on the effect of dopants on the functional polymers are of great academic and practical importance.This study is to explore the influence of glassy and rubbery states of polymer on the solvent diffusion and the effect of residual solvent on the protonization energy of calixarene （CA） by using molecular dynamics and quantum mechanics calculations, respectively. Molecular dynamics （MD） simulation of the glass transition temperature of methyl methacrylate-acrylamide calixarene was performed based on the theory of free volume. The obtained free volume-temperature curve indicates that the glass transition temperature is about 395 K, which is in good agreement with that from the literature.The mean square displacement （MSD） curves were obtained at different temperatures in both glassy and rubbery state by using MD method. The MSD results indicate that the diffusion coefficients are much smaller in glassy state than in rubbery state. The effect of residual solvent on the protonization energy of CA was calculated by using density functional theory （DFT） method. The results indicate that the presence of solvent could enhance the degree of the protonization of the calixarene in polymer, but it is much weaker than MMA copolymer.

关 键 词：分子动力学 玻璃化温度 扩散系数 解离能 

分 类 号：TQ015.9[化学工程] O631[理学—高分子化学]