Abstract:

Nano-metallic Cu and carbon material graphene nanoplatelets(GnPs) were chosen to modify organic phase change material(PCM) myristic acid(MA). The Cu/MA hybrid PCMs were prepared by adding the Cu at different mass fraction(1%, 2%, 3%, 4%) into MA, and the GnPs/MA hybrid PCMs were produced by adding the GnPs at various mass fraction(1%, 2%, 3%) into MA. Thermal properties of the hybrid PCMs were determined by using differential scanning calorimetry(DSC) analysis and transient hot-wire method. Besides, the microscopic, chemical and crystalline structure of the hybrid PCMs were characterized by scanning electron microscope(SEM), fourier transformed infrared(FT-IR) and X-ray diffraction(XRD). The results indicated that solid and liquid thermal conductivity of the Cu/MA hybrid PCMs increased linearly with the increase of Cu content. The solid thermal conductivity of 1%(mass) GnPs/MA hybrid PCM significantly raised by 101.51% compared to that of pure MA, and the thermal conductivity of hybrid PCMs kept increasing with the increase of GnPs mass fraction but increment extent slowed down. FT-IR spectra showed that the interactions between Cu and MA, and GnPs and MA were physical. DSC analysis demonstrated that both supercooling degree and phase change latent heat of MA reduced with the addition of Cu or GnPs. With the increase of mass fraction, the phase change latent heat of hybrid PCMs decreased gradually. The time of thermal energy release of 4%(mass) Cu/MA and 3%(mass) GnPs/MA hybrid PCMs decreased by 23.4% and 38.7% respectively compared to that of pure MA. After 4%(mass) Cu/MA and 3%(mass) GnPs/MA hybrid PCMs experiencing 300 accelerated thermal cycles, the crystalline structure and phase change temperature basically stayed unchanged, while phase change latent heat reduced to approximate 168 J·g^-1 and 181 J·g^-1 respectively, which still met the requirements of heat storage and release. Both materials had good thermal cycling reliability.

Key words: myristic acid, nanomaterials, hybrid phase change heat storage materials, thermal property, interaction, stability

摘要：

选用纳米金属Cu和碳素材料石墨烯纳米片（GnPs）为改性剂分别添加至十四酸（MA）中，制备出Cu质量分数为1%、2%、3%和4%的Cu/MA混合相变蓄热材料及GnPs质量分数为1%、2%和3%的GnPs/MA混合相变蓄热材料，并对混合相变材料性能进行表征。结果表明：Cu/MA固态和液态热导率随Cu质量分数增加呈线性提高，1%（质量）GnPs/MA固态热导率较纯MA显著提高101.51%，随GnPs质量分数增加，热导率增幅减缓；FT-IR谱图表明Cu与MA及GnPs与MA间的混合均为物理作用；DSC结果显示添加Cu或GnPs可降低MA的过冷度和相变潜热，且随质量分数增加，相变潜热逐渐降低；4%（质量）Cu/MA和3%（质量）GnPs/MA放热时间相比于纯MA分别减少了23.4%和38.7%；4%（质量）Cu/MA和3%（质量）GnPs/MA在经历300次快速热循环试验后，晶体结构和相变温度基本保持不变，相变潜热分别降至168 J·g^-1和181 J·g^-1左右，仍满足蓄放热要求，两种材料均具有良好的热循环稳定性。

关键词: 十四酸, 纳米材料, 混合相变蓄热材料, 热性能, 相互作用, 稳定性