六方氮化硼的辐射剥离及高性能耐辐射高分子纳米复合材料制备研究

The combination of polymer and boron nitride nanosheets (BNNS) can be expected to obtain advanced polymer nanocompoistes with excellent radiation-resistance performance, which have great significance in the areas of national defense and nuclear power industry. However, the massive preparation of BNNS is still a challenge due to the special strong intermolecular interaction in the crystals of BN. Based on the research of the ionization radiation effects of BNNS, this project plans to combine the γ-ray radiation and chemical intercalation techniques at the first time, investigate the exfoliation and modification effects of various intercalators and active functional molecules on hexagonal boron nitride (h-BN) crystals under different high energy radiation environments, and develop the new methods for one-step fabrication of modified exfoliated BNNS at ambient temperature and normal pressure. The research on the preparation of poly(ethylene terephthalate)/BNNS, epoxy/BNNS, and polymer/3D BNNS aerogel composites will be further developed. In addition, the principles of the changes in the chemical and phase structures, physical and mechanical properties of these three kinds of polymer nanocompoiste systems before and after being irradiated by Co-60 γ-ray are also studied. As a consequence, the optimal preparation method and radiation resistant mechanism of polymer/BNNS nanocomposites with excellent radiation-resistance performance will be proposed. The results of this project should not only enrich the theories of radiation chemistry and the radiation synthesis technique, but also open new ideas and methods on the fabrication of new two-dimensional nanomaterials and advanced polymer composites.

氮化硼纳米片(BNNS)具有优异耐辐射性能，与高分子材料复合得到的高性能耐辐射材料，对国防和核能领域意义重大。但由于BN特殊的分子间作用力，BNNS规模制备和改性依然困难。本申请项目拟利用六方BN(h-BN)的电离辐射效应，首次将γ射线辐射与化学插层技术结合，考察多种插层试剂和功能分子在不同辐照环境中对h-BN的剥离与修饰效果，探求常温下一步实现辐射剥离制备和修饰BNNS的新方法。在此基础上，开展BNNS与聚对苯二甲酸乙二醇酯和环氧树脂复合材料，并构筑连续导热的BN三维气凝胶网络/高分子复合材料研究，考察三类高分子/BNNS复合体系在高能射线辐照前后化学结构、相态结构、物理性能以及机械性能的变化规律，获得高性能耐辐射高分子/BNNS纳米材料的最佳制备方法及其耐辐射机理。本申请项目研究成果不仅丰富了辐射化学理论和辐射合成技术，也为新型二维纳米材料和先进高分子复合材料的制备提供新思路和新方法。

六方氮化硼（h-BN）具备优异的热稳定性、导热性、耐辐射性和中子吸收性能，将其剥离后得到的二维氮化硼纳米片（BNNS）具有低密度、高导热和高比表面积等特性。因此，BNNS被认为是目前在耐高能射线领域最具有应用前景的材料之一。然而，BNNS表面缺乏活性位点，与高分子材料相容性差，且h-BN层间的“lip-lip”相互作用和惰性B-N键，严重阻碍了h-BN的剥离和改性。因此，如何有效破坏h-BN层间相互作用，并表面改性BNNS是制备高性能耐辐射BNNS复合材料的关键。本项目研究，按计划通过预辐射接枝、辐射剥离和辅助球磨剥离功能化等方法，实现了BNNS的高效剥离及BNNS的表面功能化。经过四年的研究，取得了以下主要研究成果：(1)研究了剥离前后h-BN的γ-射线辐射效应，采用预辐射法实现了BN的表面改性，表征了其光催化性能；(2)采用辐射诱导-还原剥离法，利用离子还原、团聚的体积膨胀效应，一步法得到Ni纳米粒子负载的BNNS，并研究了相关催化活性；(3)利用球磨法批量制备了单宁酸或壳聚糖修饰的BNNS，构筑了高性能耐辐射压敏传感器和复合气凝胶；(4)采用辐射法制备了BNNS/GO复合气凝胶和BNNS高分子复合气凝胶，考察了耐辐射性能和催化性能；(5)通过溶液共混法制备了h-BN/EP复合材料，考察其在辐照条件下的结构和性能变化；(6)采用溶液共混法制备了BN/PET复合材料，研究了复合材料的导热、介电和耐辐射性能，表征了BN/PET复合材料的辐射化学效应。研究结果表明，BNNS表面改性的高分子复合材料的耐辐射性能有较大提高，为耐辐射多功能材料的设计和制备提供了实践参考。.以上研究成果共发表学术论文18篇，其中在Journal of Materials Chemistry A、Applied Surface Science 和Chinese Chemical Letters等SCI或CSCD检索期刊上发表论文共14篇，还有数篇论文正在投稿过程中；获得发明专利2项。因此，本项目已达到预期的研究目标。