复合材料检测配方中心，吸水树脂试验

 高导热的填料虽然能够提升木质基复合相变储热材料的储放热速率，但存在的易团聚现象无法使其均匀分散于材料内部。本研究旨在利用溶液还原法，由内而外地在轻木基体内原位生成单分散的金属铜颗粒，为提高木质基复合相变储热材料的储放热性能探索绿色、经济的道路。  方法  首先利用酸性亚氯酸钠溶液对轻木进行脱木素处理以提高其对相变材料的封装效率。然后利用CuSO4溶液与抗坏血酸溶液在脱木素轻木内利用溶液还原法多次循环制备单分散金属Cu颗粒，并将反应完全后的轻木利用真空浸渍法与石蜡（PW）制备具有Cu颗粒强化导热的木基复合相变储热材料。采用场发射电子显微镜（SEM）、红外光谱分析（FTIR）、X射线衍射仪（XRD）、差式扫描量热仪（DSC）、导热系数测试仪和温度巡检仪对材料的微观、结晶、化学结构及储放热性能进行评价。  结果  轻木经脱木素处理后其对石蜡的封装效率从64.9%提升至了82.6%。经过抗坏血酸对Cu2+的还原作用，在轻木基体内原位制造出了Cu。然而循环次数过少，Cu不能均匀地分布在木材基体内，而过多的循环次数则会过量地影响轻木对相变材料的封装效果；其中3次的循环次数为合适，以此所制备的复合相变储热材料导热系数提升了1.76倍，熔融与凝固潜热分别高达143.7、142.9 J/g，同时储热与放热时间分别缩短了23.7%与32.6%，展现出了更好的温度调节潜力。  结论  利用溶液还原法能够有效地在轻木基体内均匀制备金属Cu颗粒，并且以3次循环制备的Cu颗粒强化导热的木基复合相变储热材料储放热性能较好。

Abstract:   Objective  Although high thermal conductivity fillers can improve the heat storage and release rate of wood-based phase change heat storage composite materials. The agglomeration of nanoparticles is not conducive to their uniform dispersion in the material. The purpose of this paper is to use the solution reduction method to in-situ generate monodisperse copper particles in the balsa wood (Ochroma pyramidale) matrix from the inside to outside, so as to develop a green and economic way to improve the heat storage and release properties of phase change heat storage wood-based composite materials.  Method  Firstly, the balsa wood was delignified with acid sodium chlorite solution to improve the packaging efficiency of phase change materials. Then, the monodisperse Cu particles were prepared by the solution reduction method in delignified balsa wood with CuSO4 solution and ascorbic acid solution by cyclic reaction, and the paraffin wax (PW) was added to the wood-based composite by vacuum impregnation method. Field emission electron microscope (SEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimeter (DSC), thermal conductivity tester and temperature inspection instrument were used to evaluate the microstructure, crystallization, chemical structure and heat storage and release properties of the materials.   Result  After delignification, the encapsulation efficiency of balsa wood increased from 64.9% to 82.6%. After the reduction of Cu2+ by ascorbic acid, Cu was produced in-situ in the balsa wood matrix. However, if the number of cycles was too small, Cu can not be evenly distributed in the wood matrix, and if the number of cycles was too large, the packaging effect of balsa wood on phase change materials will be excessively affected. The three cycles were the most appropriate. The thermal conductivity of the composite phase change heat storage material prepared by this method was increased by 1.76 times, the melting and solidification latent heat were as high as 143.7 and 142.9 J/g, respectively, and the heat storage and heat release time were shortened by 23.7% and 32.6%, respectively, showing a better potential for temperature regulation.   Conclusion  The solution reduction method can effectively prepare Cu particles uniformly in the balsa wood matrix, and the wood-based composite phase change heat storage material with Cu particles prepared by three cycles to enhance heat conduction has good heat storage and release performance.