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采用纳米孔模板润湿技术制备了直径为200 nm的低密度聚乙烯(LDPE)纳米线阵列,并利用纳秒激光闪光法测量了20—80℃时LDPE纳米线阵列的热导率.测量得到室温时LDPE纳米线阵列的热导率为2.2W/mK,大约比其体材料的热导率高1个数量级,并且纳米线阵列的热导率随温度的升高略有增加.忽略纳米线之间的声子散射.估算得到室温下单根LDPE纳米线的热导率高于5 W/mK.本文制备LDPE纳米线热导率的提高源自其分子链定向度增加导致的低维导热效应的增强,纳米线的分子链定向度受工艺过程中流体剪切、振动、分子链迁移运动、纳米孔约束等几种因素的综合影响.
Low density polyethylene (LDPE) nanowire arrays with a diameter of 200 nm were prepared by nanoporous template wetting technique and the thermal conductivity of LDPE nanowire arrays at 20-80 ℃ was measured by nanosecond laser flash method. The thermal conductivity of the LDPE nanowire arrays at room temperature is 2.2 W / mK, which is about one order of magnitude higher than the thermal conductivity of the bulk material and the thermal conductivity of the nanowire arrays slightly increases with increasing temperature. The thermal conductivity of single LDPE nanowires at room temperature is estimated to be higher than 5 W / mK.The improvement of the thermal conductivity of LDPE nanowires prepared in this paper is due to the low dimensional thermal conductivity caused by the increase of the orientation degree of the molecular chains Effect of the enhancement of the molecular orientation of the nanowires by the process of fluid shear, vibration, movement of molecular chains, nanopore constraints, and several other factors combined.