基于高内相乳液制备储热复合材料及其性能研究

High internal phase emulsion (HIPE)-based composites are promising for latent heat storage, because they simultaneously encapsulate and shape-stabilize phase change materials (PCMs). However, fabrication and properties of such composites involve several issues. The process for the composite preparation is complex and the resulting composites suffer from super-cooling and low mechanical properties. This project aims to fabricate novel HIPE-based composites for latent heat storage applications by encapsulating alkanes-based PCMs within graphene oxide-stabilized oil-in-water HIPEs, followed by HIPEs solidification from isocynates and pectin or lignin at interfaces of the dispersed phase and the continuous phase. A series of HIPEs and polyHIPEs will be fabricated by varying graphene oxide contents, polyols, isocynates, polyols/isocynates ratios, PCMs and dispersed phase fractions. The effects of HIPE composition, average droplet diameter and droplet distribution on the morphologies (pore size and size distribution), physicochemical properties (amphiphilicity, thermal conductivity and mechanical properties) and heat storage performance (endothermic temperature, exothermic temperature and latent heat) of the resulting polyHIPEs will be investigated. PolyHIPEs/fabrics will be fabricated by incorporating HIPEs with fabrics followed by polymerization of HIPEs, and the effects of fabrics on the morphology, physicochemical property and heat storage performance of the polyHIPEs/fabrics will be also investigated.

基于高内相乳液(HIPEs)制备的储热复合材料可同时实现对相变材料的包覆与定形，具有极大的潜力，但仍存在制备复杂、过冷现象严重和力学性能差等诸多问题。本项目拟借助HIPEs的可调控性，合成以高级烷烃相变材料为分散相、氧化石墨烯稳定的水包油型HIPEs，并通过异氰酸酯在HIPEs连续相和分散相界面处交联胶质或木质素，固化HIPEs，制备储热复合材料polyHIPEs；揭示HIPEs组成(氧化石墨烯浓度、多羟基化合物与异氰酸酯种类与比例、相变材料熔点与分散相体积分数)、粒径与粒径分布对polyHIPEs形貌(孔径及其分布)、理化性质(导热性、润湿性与力学性能)与储热性能(吸热温度、放热温度、吸收与释放的热量)的影响关系。进而，将HIPEs与织物进行复合，并固化HIPEs，制备织物增强的新型储热复合材料polyHIPEs/织物；并研究织物对polyHIPEs/织物形貌、理化性质与储热性能的影响。

本研究针对高内相乳液(HIPEs)基储热复合材料制备与性能中存在的制备复杂、过冷现象严重和力学性能差等诸多问题，通过利用HIPEs的可调控性，合成了以相变材料十八烷为分散相的水包油型HIPEs，并通过光引发界面自由基聚合、界面Michael加成反应或界面交联反应等固化HIPEs，合成了具有闭孔结构的polyHIPEs，同时实现了对十八烷的包覆和定形，制备了储热复合材料polyHIPEs；并揭示HIPEs组成(稳定剂种类、单体种类、十八烷体积分数)、粒径及其分布对polyHIPEs形貌、理化性质与储热性能(吸热温度、放热温度、储热密度等)的影响关系。研究表明该储热复合材料polyHIPEs具有优异的压缩性能，可被压缩至原高度的30%而不会破碎；且通过选用合适的单体，制备的储热复合材料具有柔性。该储热材料具有极高的储热密度，最高可达250 J/g，略高于纯十八烷的储热密度，且具有优异的重复使用性，可反复加热-冷却100次，而吸热温度、放热温度和吸热放热峰形未发生明显变化。将HIPEs与适当的织物复合，再固化HIPEs，制备了织物增强的储热复合材料polyHIPEs/织物，织物的存在略微降低了polyHIPEs的储热密度，但是储热温度、放热温度和重复使用性得以保持，且polyHIPEs/织物拉伸性能得到大大提高，其拉力甚至高于相应的织物，克服了脆性polyHIPEs质脆易碎的缺点。总之，通过本研究，成功合成了具有闭孔结构的polyHIPEs，实现了对相变材料的包覆和定形，制备了基于乳液新型储热复合材料，解决该材料制备复杂、过冷现象严重与力学性能差的问题，具有重要理论意义。并且，这种储热复合材料具有储热密度高、传热比表面积大、重复使用性好和具有柔性等优点，很可能应用于露营装备和特种车辆领域，具有重要实用意义。