高性能PET/石墨烯纳米复合材料的原位聚合法制备及其结构与性能研究

项目名称： 高性能PET/石墨烯纳米复合材料的原位聚合法制备及其结构与性能研究

项目编号： No.50803067

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 管国虎

作者单位： 中国科学院化学研究所

项目金额： 20万元

中文摘要： 本项目研究采用原位聚合法合成聚对苯二甲酸乙二酯（PET）/石墨烯纳米复合材料，并研究这类材料的结构与性能之间的关系。我们采用氧化石墨（GO）为起始原料，利用GO片层表面和层间大量的活性基团来对其进行表面有机改性，再负载缩聚催化剂，经插层聚合得到纳米复合材料。GO的表面有机改性分别采用有机小分子插层改性和表面接枝功能性聚合物两种方式。我们在研究中发现GO片层表面弱键断裂能够引发烯类单体的自由基聚合，通过FTIR、NMR、元素分析、X射线光电子能谱（XPS）以及透射电镜（TEM）等手段证实了接枝聚合反应的发生。接下来，我们把新型聚酯缩聚催化剂负载到有机改性GO片层表面，用上述制备的GO催化剂催化聚酯缩聚反应，经原位插层缩聚制得PET/石墨烯纳米复合材料。通过GO的表面改性与聚酯缩聚催化剂的负载相结合，使得GO纳米片层在聚合物基体中具有良好的分散性，通过扫描电镜（SEM）和TEM观察到剥离的石墨片层均匀的分散在基体中。并利用聚合反应热在插层聚合的同时实现GO片层的热解还原。导电性能研究发现石墨烯纳米片层的引入使得PET具有很低的导电逾渗阈值，而且石墨烯的引入使材料的力学性能得到明显改善。

中文关键词： 石墨烯；聚酯；纳米复合材料

英文摘要： This research program dealt with in-situ synthesis and characterization of PET/graphene nanocomposites using a nano-sol catalyst supported on the surface of graphite oxide (GO) nanosheets.GO was used as the starting material, and two approaches were used to decorate the surface of GO. The first one is using organic modifiers with short alkyl chains, and the second one is grafting polymer chains to the GO surface. It has been found that GO can be directly used as a polymerization initiator for vinyl monomers. Poly(vinyl pyrrolidone) (PVP) can be readily grafted to the surface of GO sheets by using GO as the initiator, which was confirmed by FTIR, NMR, Elementary Analysis (EA), XPS. A novel polycondensation catalyst was introduced into the gallery space of the organically modified GO through an ion exchange process which is analogous to that of layered silicates. In-situ intercalative polymerization and subsequent exfoliation of graphene nanosheets were achieved by using the GO based polycondensation catalyst. Thermal reduction of GO during the in-situ polycondensation was achieved, which is confirmed by TGA, XPS, EA and electrical measurements. The preparation of PET/graphene nanocomposites can be greatly simplified because the nanoscale dispersion and thermal reduction can be achieved simultaneously. With the intorduction of graphene sheets, breaking elongation of PET was remarkably enhanced, while the tentile strength, flexural strength and modulus shew modest improvement. The electrical conductivity of PET was also improved considerably by introduction of graphene sheets, exhibiting a very low electrical percolation threshold at about 0.1wt%, while the PET/NG composites shew a broad percolation transtion. Such a rather low electrical percolation threshold can be explained by the extraordinarily large specific surface area of graphene sheets and their excellent homogeneous dispersion in the matrix.

英文关键词： graphene; nanocomposites; polyesters