Abstract:

Fatty amine, as an organic phase change material, has the characteristics of high enthalpy of phase change, non-toxic and low corrosion and stable chemical properties. It is a good phase change material for the medium and low temperature phase change energy storage. The phase change microcapsules were prepared with the tetradecylamine-hexadecylamine phase change material as the core material and silica as the wall material using the sol-gel method. The thermal conductivity of the microcapsules was improved by adding inorganic material graphene nanoparticles to the phase change material. The morphology and thermal properties of the microcapsules were analyzed by FTIR, SEM, DSC and TG. The effects of deionized water amount, the content of graphene nanoparticles and the amount of tetraethyl orthosilicate (TEOS) on the preparation of microcapsules were analyzed. The experimental results showed that the microcapsules with good morphology and thermal properties could be prepared when the deionized water was 10mL, the core material was added with 0.05% graphene nanoparticles and the mass ratio of TEOS to core material was 10∶3. The addition of graphene nanoparticles could increase the thermal conductivity of microcapsules to 0.28W/(m·K) increased by 87% compared to the phase change microcapsules without graphene. The particle size of microcapsule was about 2μm. The microcapsules had spherical morphology. The melting temperature and solidification temperature were 26.31℃ and 23.46℃, respectively. The phase transformation enthalpy of microcapsules was 147.7J/g. The encapsulation rate was about 59.3%. No chemical reaction occurred in the process of microcapsules preparation. TG test showed that microcapsules could exist stably at room temperature.

Key words: microcapsules, phase change, enthalpy, stability, graphene, preparation

摘要：

脂肪胺具有相变焓大、无毒低腐蚀、化学性质稳定等优点，是理想的中低温相变储能材料。采用溶胶-凝胶法，以十四胺-十六胺二元相变材料为芯材，二氧化硅为壁材制备了相变微胶囊。通过向相变材料中添加无机材料石墨烯纳米颗粒，提高相变微胶囊的导热性能。采用FTIR、SEM、DSC和TG等测试手段分析了微胶囊的形貌和热性能，研究了微胶囊制备过程中去离子水量、石墨烯纳米颗粒添加量以及硅酸四乙酯（TEOS）用量对微胶囊制备的影响。实验结果表明，当去离子水量为10mL、芯材中添加质量分数比0.05%的石墨烯纳米颗粒、TEOS和芯材质量比为10∶3时，可以制备出形貌、热性能良好的微胶囊。石墨烯纳米颗粒的加入可以将微胶囊的热导率提高至0.28W/(m·K)，提高了87%。微胶囊粒径分布在2μm左右，形貌呈球形，融化温度和凝固温度分别为26.31℃和23.46℃，相变焓为147.7J/g，包裹率约为59.3%。十四胺-十六胺相变材料在形成微胶囊的过程中不发生化学反应，TG测试表明微胶囊在常温下能够稳定存在。

关键词: 微胶囊, 相变, 焓, 稳定性, 石墨烯, 制备