石墨的固相剪切石墨烯化及其与聚氯乙烯的纳米复合

Solid State Shear Graphenization of Expanded Graphite and Preparation of Graphene/Polyvinyl Chloride Nanocomposites

采用微波辐照市售可膨胀石墨制备膨胀石墨(EG),通过EG-聚氯乙烯(PVC)、EG-PVC-氯化聚乙烯(CPE)和EG-PVC-聚氨酯热塑性弹性体(TPU)等的固相剪切共碾磨(S3M)制备了EG/PVC,EG/PVC-CPE和EG-PVC-TPU复合粉体,进一步模压成型得到EG/PVC,类石墨烯/PVC/CPE和石墨烯-PVC-TPU复合材料。用粒度分析、扫描电镜、透射电镜、X射线衍射和原子力显微镜等手段表征了复合粉体及其复合材料的结构与性能。结果表明,S3M实现了体系的粉碎、分散和EG与PVC的纳米复合;CPE和TPU的加入实现了EG的进一步剥层,使石墨片层的厚度达到1~5层,达到了少层石墨烯水平,实现了EG石墨烯化的目标。当EG质量分数在3%时,类石墨烯/PVC-CPE复合材料电导率呈指数上升,提高了8个数量级;当EG质量分数超过4%时,电导率再次激增,出现第2次逾渗现象;在5%时,电导率达0.22 s/m,表现出良好的导热、抗静电和电磁屏蔽功能。石墨烯/PVC-TPU纳米复合材料的电导率变化与类石墨烯/PVC-CPE复合材料类似,而且导热、抗静电和电磁屏蔽性能更好。

Expanded graphite(EG) was got from expandable graphite by microwave irradiation, the binary systems of EG/polyvinyl chloride(PVC), the ternary system of EG/PVC-chlorinated polyethylene(CPE) and EG/PVC-thermoplastic polyurethane elastomer(TPU) compounded powder were prepared by solid state shear milling(S~3M) based on pan mill. Structure and properties of EG/PVC, EG/PVC-CPE and EG/PVC-TPU co-powder were characterized by SEM, TEM, XRD, analysis of particle size and distribution. The results show that S~3M can realize the pulverizing,dispersion and compounding of EG-PVC or EG-PVC-CPE or EG-PVC-TPU, further more demonstrate that mixing CPE with EG-PVC and TPU with EG-PVC is benefit for the exfoliating graphite. The thickness of the graphite in EG/PVC-TPU co-powder is equivalent to 1~5 layers. The goal of changing the expanded graphite to graphene was achieved;when the EG mass fraction is 3 %, the electrical conductivity of EG/CPE-PVC composites increases the eight orders of magnitude. When the EG mass fraction exceeds 4%, the conductivity surges again and a second percolation occurs.When the EG mass fraction exceeds 5%, the conductivity reaches 0.22 S/m, showing good thermal conductivity,antistatic and electromagnetic shielding performance. Graphene/PVC-TPU nanocomposites have similar conductivity changes to graphene-like/PVC-CPE composites, and better thermal conductivity, antistatic and electromagnetic shielding. S~3M is an effective way to prepare graphene/polymers composites.