【摘要】 以4种不同类型的纳米碳材料(纳米石墨烯GNP-B、纳米石墨烯GNP-C、多壁碳纳米管MWCNTs和石墨化多壁碳纳米管G-MWCNTs)为填料,采用两步法制备了不同质量分数(0.2%～3.0%)的纳米复合相变材料。扫描电镜分析表明纳米碳材料较好地被石蜡包覆,由于纳米碳材料具有不同的管状和层状结构,纳米复合材料表现出不同的比表面积。红外光谱分析(FT-IR)表明纳米碳材料与石蜡之间未发生化学反应,仅以物理方式彼此结合。差示扫描量热分析(DSC)表明,纳米碳材料的种类和浓度对纳米复合材料相变温度的影响很小,熔化和凝固过程中最大的相变温度差分别为0.74℃和1.11℃。但随碳纳米颗粒质量分数的增加,复合相变材料的相变潜热值逐渐减小。对于4种纳米复合材料,当质量分数为3%时,4种纳米复合材料(MWCNTs、G-MWCNTs、GNP-C和GNP-B)熔化过程的相变潜热相比纯石蜡分别降低了7.3%、13%、12%和12.8%,凝固过程的相变潜热相比纯石蜡分别降低了11.2%、19.9%、17.8%和11.4%。更多还原

【Abstract】 Four types of nanocomposite PCMs were prepared by mixing paraffin with multi-wall carbon nanotubes(MWCNTs),graphitized MWCNTs and nanographenes with different layer numbers(GNP-B,GNP-C).The SEM images analysis showed that the carbon nanofillers were well coated with multiple layers of paraffin.Moreover,the surface of the composites showed different images due to the difference of tubular and flaky structures of the carbon nanofillers.The FT-IR spectrum proved that it was a physical interaction between paraffin and the carbon nanofillers and there was no chemical reaction in the infiltrating process.There was no clear relationship between the phase change temperature and the type and loading of the carbon nanofillers.It showed that phase change enthalpy of nanocomposite PCM decreased gradually with the increasing of the loading of carbon nanofillers.Among the four kinds of carbon nanofillers,at the highest loading of 3 mass% for MWCNTs,G-MWCNTs,GNP-C and GNPB,the melting enthalpies were lowered by 7.3%,13%,12% and 12.8% compared with pure paraffin for 196.2 J/g,respectively.Similarly,the freezing enthalpies were lowered by 11.2%,19.9%,17.8% and 11.4%.更多还原