水基石墨烯纳米流体的制备及导热性能

摘要

利用改性Hummers法制备氧化石墨烯(GO),并以硼氢化钠为还原剂通过控制还原时间制得不同还原程度的还原氧化石墨烯(rGO);采用两步法将GO或rGO分散在水中,通过控制超声时间得到不同粒径的水基石墨烯纳米流体;测量纳米流体的导热系数,研究测量温度、石墨烯含量、粒径和还原时间对它的影响.结果表明:水基石墨烯纳米流体的导热系数显著大于基液的,且随着测量温度、石墨烯含量的增加呈线性增大;与GO-水纳米流体相比,rGO-水纳米流体导热性能更好,并且其导热系数随着还原时间的延长而增大;水基石墨烯纳米流体的导热系数随着粒径的增加而增大,且粒径对还原15min的rGO-水纳米流体导热系数影响最为显著.%Graphene oxide(GO) was obtained through the modified Hummers method, then reduced graphene oxide(rGO) with different reduction degrees was further prepared taking sodium borohydride as the reducing agent by controlling the reduction time.Water based graphene nano-fluids with different particles sizes and various contents were produced using the two-step method, that is, dispering GO or rGO into water by controlling the ultrasonic time.Thermal conductivity of the nano-fluids was further measured to study the influence of temperature, content, particle size and reduction time.The results show that the thermal conductivity of water based graphenen nano-fluids is significantly greater than that of the base fluid, which increases linearly with the increase of temperature and content.Compared with GO-water nano-fluid, the thermal conductivity of rGO-water nano-fluid is better, which also improves with the increase of reduction time.The thermal conductivity of water based graphene nano-fluids improves with the increase of particle size.The particle size has the most significant impact on the thermal conductivity of rGO-water nano-fluid when the reduction time is 15min.