蒙脱土/还原石墨烯/聚乙烯醇复合薄膜的制备及其导热性能

摘要

In this paper,graphene oxide (GO) and exfoliated montmorillonite (MMT) hybrid (MMT/GO) were used as a dual filler to prepare MMT/graphene/poly(vinyl alcohol) (MMT/rGO/PVA) nanocomposites via solution blending.Our results show that GO prepared at-40 ℃ exhibits less defects,suggesting higher thermal conductivity when filled with polymer composites.The presence of exfoliated MMT sheets greatly prevents the aggregation of graphene sheets because of the hydrogen-bond interaction and crosslinking effects (sodium ions serve as "crosslinkers") between GO and MMT sheets.Meanwhile,the hydrogen bonds between the PVA matrix and the MMT/GO dual filler improve their dispersion and their interfacial interaction,resulting in the significant decrease in interfacial thermal resistance.The effects of the ratio of MMT to GO and the filling percentage of the dual filler on the thermal conductivity of MMT/rGO/PVA nanocomposites were investigated.The thermal conductivity of MMT/rGO/PVA nanocomposites with 12% filling of MMT/GO (2∶1,by mass)dual filler is 66.4 W/(m·K),which is 132 times greater than that of pure PVA film.%以蒙脱土/氧化石墨烯(MMT/GO)为二元填料,采用一步溶液共混法,并经水合肼还原,制备得到蒙脱土/还原石墨烯/聚乙烯醇(MMT/rGO/PVA)复合薄膜,研究了GO的氧化程度、MMT/GO二元填料的组成及质量分数对复合薄膜导热性能的影响.结果表明:低温浴条件下制备得到的GO具有更完整的sp2杂化碳晶格,有利于rGO导热性能的发挥;MMT片层能有效阻止GO在还原过程中团聚,使rGO在复合薄膜中形成有序排列结构,有利于复合薄膜导热性能的提升;同时,由于MMT/GO二元填料能与PVA基体之间形成氢键,大大改善了填料和聚合物之间的界面结合力,降低了界面热阻,进一步提高了复合薄膜的导热性能.当MMT与GO的质量比为2∶1,复合薄膜中MMT/GO二元填料的质量分数为12%时,MMT/rGO/PVA复合薄膜的热导率达到66.4 W/(m·K),比纯PVA(<0.5 W/(m·K))至少提高了132倍.