摘要
采用熔融共混法制备石蜡/膨胀石墨复合相变材料,使用半导体粉末电阻率测试仪对天然鳞片石墨、提纯石墨、可膨胀石墨、石蜡/膨胀石墨复合相变材料在不同压强下的电阻率进行测试。发现所有材料的电阻率都随压强的增加而减小,对导热性能最好的相变材料进行7次重复测试,材料电阻率在0.210~0.535?·cm之间变化,依然小于1?·cm,属于低电阻率材料。根据测试数据计算不同压强情况下相变材料单位体积蓄热量、密度、体积和电阻值。材料的单位体积蓄热量和密度随压强增大而增大,体积和电阻则相反,压强在4~10MPa之间时物理性能比较稳定,在10MPa左右时,相变材料电阻值比天然鳞片石墨最大增大884倍、体积1.9倍、密度0.6倍,单位体积蓄热量同比4 MPa时最大增加22.8%,压缩之后单位体积蓄热量提高。说明膨胀石墨/石蜡复合材料属于低电阻率相变材料,应用于沥青路面,能够实现升温和降温的双重效果。
Expandable graphite-paraffin composite phase change materials were prepared by a melt-blending process. The resistivity of natural flake graphite, purified graphite, expandable graphite, paraffin-expanded graphite composite phase change materials formed at different pressures was measured using a semiconductor powder resistivity tester. The results showed that the resistivity of all materials decreased with increasing pressure, seven repeated tests were performed on the material with the best thermal conductivity, and the resistivity of the material varied between 0.210-0.535 Ω·cm, which was lower than 11 Ω·cm and hence can be classified as a low-resistivity material. According to the measurement data, the amount of heat storage per unit volume, density, volume and resistance of the composite phase change materials were calculated. The amount of heat storage per unit volume and density of the material increased with increasing pressure, however, the resistivity and volume showed the opposite as expected. The physical properties of materials were found to be stable when the formation pressure was between 4 and 10 MPa;at about 10 MPa, the resistivity of the phase change material was 884 times larger than that of natural scale graphite, 1.9 times the volume and 0.6 times the density. The amount of heat storage per unit volume was 22.8% higher than that at 4 MPa. It was shown that the expanded graphite/paraffin composite was a low resistivity phase transition material, which can be applied on asphalt pavement, achieving both heating up and cooling down effects.
作者
徐众
黄平
吴恩辉
侯静
李军
刘黔蜀
XU Zhong;HUANG Ping;WU En’hui;HOU Jing;LI Jun;LIU Qianshu(College of Vanadium and Titanium,Panzhihua University,Panzhihua 617000, Sichuan, China;Sichuan Provincial Engineering Laboratory of Solar Technology Integration,Panzhihua 617000, Sichuan, China;Application and Solar Technology Integration Sichuan Provincial Key Laboratory of University,Panzhihua 617000,Sichuan,China)
出处
《储能科学与技术》
CAS
CSCD
2019年第2期371-378,共8页
Energy Storage Science and Technology
基金
国家级大学生创新项目(0191100349)
四川省教育厅太阳能高校重点实验室项目(2018TYNSYS-Y-04)
关键词
天然鳞片石墨
可膨胀石墨
复合相变材料
电阻率
natural flake graphite
expandable graphite
composite phase change material
resistivity
