Abstract:

BN-OH nanosheets were prepared by using glucose-assisted ball milling of hexagonal boron nitride (BN), and glucose was successfully grafted onto BN molecules through B－O chemical bonding. Uniform isolated network structures were obtained by co-precipitation of different contents of BN-OH nanosheets with natural latex (NR) particles prepared by latex co-precipitation, and physical cross-linking between BN-OH nanosheets and NR molecular chains was formed by hydrogen bonding assisted by the proteins around the NR latex particles. The effects of the content of BN-OH nanosheets on the crosslink density, mechanical properties, thermal conductivity and gas barrier properties of BN-OH/NR nanocomposites were investigated. In a certain range, with the increase of BN-OH nanosheets, the tensile strength and constant tensile stress of BN-OH/NR nanocomposites increased, the energy storage modulus rose and the loss factor decreased, which indicated the good reinforcing effect of the BN-OH nanosheets and strong two-phase interfacial bonding force between BN-OH nanosheets and NR molecular chains. The good dispersion of the BN-OH nanosheets, the formation of the segregation network structure and the strong interfacial interactions formed by protein-assisted physical cross-linking blocked the diffusion of gas molecules, while heat was released along the lapped BN-OH nanosheets, resulting in the good thermal conductivity and gas barrier properties of the BN-OH/NR composites. Thermal conductivity of 20% BN-OH/NR nanocomposites was 0.319W/(m·K), which was improved by 94% compared with that of pure NR. The volume resistivity of BN-OH/NR nanocomposites with different contents was still much higher than the insulating critical resistivity standard, which meant that the rubber composites prepared in this paper with insulating, high mechanical properties, high thermal conductivity and good sealing performance were expected to be used as thermal interface materials in electronic components, batteries, automobiles and other fields.

Key words: composites, nanostructure, thermal conductivity, gas barrier properties, boron nitride, natural rubber

摘要：

采用葡萄糖辅助球磨六方氮化硼（BN），通过B—O化学键将葡萄糖成功接枝在BN分子上，制备得到BN-OH纳米片。将不同含量的BN-OH纳米片与天然胶乳（NR）粒子通过胶乳共沉淀制备得到了均匀的隔离网络结构，在NR胶乳粒子周围蛋白质的辅助下BN-OH纳米片与NR分子链通过氢键等形成了物理交联。考察了BN-OH纳米片的含量对BN-OH/NR纳米复合材料的交联密度、机械性能、导热性能和气体阻隔性能等的影响。在一定范围内，随BN-OH纳米片填充量的增加，BN-OH/NR纳米复合材料的拉伸强度、定伸应力增加，储能模量上升，损耗因子下降，表明BN-OH纳米片良好的补强作用和强两相界面结合作用力。BN-OH纳米片良好地分散。形成的隔离网络结构以及蛋白质辅助物理交联所形成的强有力的界面相互作用，阻隔了气体分子的扩散，同时热量沿搭接在一起的BN-OH纳米片释放出去，致使BN-OH/NR复合材料良好的导热性能和气体阻隔性能。20% BN-OH/NR纳米复合材料的热导率为0.319W/(m·K)，为导热材料，较纯NR的热导率提升了94%。而不同含量的BN-OH/NR纳米复合材料的体积电阻率仍远高于绝缘临界电阻率的标准，即本文制备的绝缘、高机械性能、高导热和良好密封性能的橡胶复合材料有望应用于电子元器件、电池、汽车等领域的热界面材料。

关键词: 复合材料, 纳米结构, 导热性能, 气体阻隔性能, 氮化硼, 天然橡胶