复合相变储冷材料的制备及性能研究

以十二烷基苯磺酸钠(SDBS)作为分散剂,多层石墨烯、TiO2/石墨烯(m(TiO2):m(石墨烯)=25∶75)和TiO2颗粒作为导热添加剂,加入到二元复合有机储冷材料中(m(壬酸):m(葵醇)=60:40),制备了复合相变储冷材料。通过吸光度、DSC和热导率测试等手段,对复合相变储冷材料的稳定性、相变温度、相变潜热及热导率进行了评价分析。结果表明,分散剂和导热添加剂的加入,对储冷材料的相变温度和相变潜热影响不大,但对热导率影响较大。当分散剂SDBS浓度为0.2 g/L,导热添加剂(分别为TiO2/石墨烯和TiO2颗粒)浓度为0.5 g/L时,复合相变储冷材料具有较好的稳定性,其热导率分别为为0.2211和0.2096 W/(m·K),相比没有加入任何导热添加剂的储冷材料的热导率(0.1738 W/(m·K)),分别提高了27.22%和20.61%;当分散剂SDBS浓度为0.3 g/L,导热添加剂多层石墨烯浓度为0.3 g/L时,复合相变储冷材料处于稳定状态,其热导率为0.2268 W/(m·K),相比0.1738 W/(m·K),提高了30.49%。由此可知,多层石墨烯可以更有效地增加复合相变储冷材料的热导率,这主要是由于石墨烯具有非常高的比表面积,有利于复合材料更加均匀地分散以及形成更加完善的网格结构,从而有效增加复合相变储冷材料的稳定性及热导率。选用多层石墨烯为导热添加剂(0.3 g/L),SDBS为分散剂(0.3 g/L),可以制备出体系最稳定、热导率最高的复合相变储冷材料。

Preparation and properties of composite phase change cold storage materials

Using sodium dodecyl benzene sulfonate(SDBS)as dispersant,multi-layer graphene,titanium dioxide/graphene(m(titanium dioxide):m(graphene)=25:75)and titanium dioxide particles as thermal conductive additives,the composite phase change cold storage materials were prepared by adding binary composite organic refrigeration storage materials(m(nonylic acid):m(sunflower alcohol)=60:40).By means of absorbance,DSC and thermal conductivity test,the stability,phase transition temperature,latent heat and thermal conductivity of the composite phase change material were evaluated and analyzed.The results showed that the addition of dispersants and thermal conductive additives had little effect on the phase transition temperature and latent heat of cold storage materials,but had great influence on the thermal conductivity.When the concentration of dispersant SDBS was 0.2 g/L and the concentration of thermal conductive additives(titanium dioxide/graphene and titanium dioxide particles,respectively)was 0.5 g/L,the composite phase change cold storage materials had better stability.Their thermal conductivity was 0.2211 and 0.2096 W/(m.K),respectively.Compared with the thermal conductivity of the materials without any thermal conductive additives(0.1738 W/(m.K)),they increased by 27.22%and 20.61%,respectively.When the concentration of dispersant SDBS was 0.3 g/L and the concentration of thermal conductive additive multi-layer graphene was 0.3 g/L,the thermal conductivity of the composite phase change material was 0.2268 W/(m.K),which was 30.49%higher than that of 0.1738 W/(m.K).It can be concluded that multi-layer graphene could effectively increase the thermal conductivity of the composite phase change cold storage materials,mainly because graphene had a very high specific surface area,which was conducive to the more uniform dispersion of the composite materials and the formation of a more perfect grid structure,thus effectively increasing the stability and thermal conductivity of the composite phase change cold storage materials.Using multi-layer graphene as thermal conductive additive(0.3 g/L)and SDBS as dispersant(0.3 g/L),the composite phase change materials with the most stable system and the highest thermal conductivity could be prepared.