石墨烯调控PEG相变材料的设计、制备及其构效关系研究
发布时间：2018-01-15 05:32
本文关键词：石墨烯调控PEG相变材料的设计、制备及其构效关系研究 出处：《西南科技大学》2017年硕士论文 论文类型：学位论文
【摘要】：相变储能材料是新型能源材料的重要组成部分,作为一种先进的储能材料,材料发生相态变化时会吸收或释放出相变潜热。相变材料不仅可以将间歇性、不稳定的能量储存起来,解决能源使用在时间和空间的不匹配问题,而且是提高太阳能、风能、地热能、工业余热等能源方面储存管理的最佳候选。在提高能源利用效率,缓解环境与能源压力方面具有重要的意义。聚乙二醇(PEG)相变材料是新型有机相变材料研究领域的重要分支,PEG具有接近人体适宜的相变温度,较高相变潜热及耐腐蚀性,相变过程近似恒温,PEG的相变材料适宜于低温,其温度可以通过分子量设计。但PEG作为相变材料目前面临以下缺点:导热率较低、相变过程易渗漏、热稳定性差的缺陷,严重阻碍了PEG相变材料的应用价值。但PEG作为相变材料目前面临以下缺点:导热率较低、相变过程易渗漏、热稳定性差的缺陷,严重阻碍了PEG相变材料的应用价值。本论文采用Hummers法制备氧化石墨烯(Graphene Oxide,GO),一步水热法制备了三维石墨烯凝胶复合PEG相变材料,采用抗坏血酸(Vitamin C,Vc)作为还原剂。这种三维网络结构不仅为PEG传热提供导热通道,而且还为解决PEG渗漏性提供了支撑载体,随着还原程度的增加,氧化石墨烯片层缺陷降低,就能够达到与石墨烯近似的热物理化学性质。与纯PEG相比,三维石墨烯凝胶复合PEG相变材料相变焓损失率低于1%,导热率提高了61.7%,PEG含量可达99.3%。材料在70℃恒温30min后,没有发生液体的渗漏现象。当还原程度最大时,热稳定性相比纯PEG提高了约20℃。另外,氧化石墨烯的表面含氧官能团以及PEG分子的可设计性,具备采用化学法制备功能化PEG相变材料的优势。本文采用SOCl2将氧化石墨烯表面的羧基官能团酰氯化,酰氯化的氧化石墨烯表面就具有高的化学反应活性,含氧官能团的减少使得氧化石墨烯缺陷降低,既提高了氧化石墨烯表面化学活性,又对氧化石墨烯进行了还原。实验选用温敏性有机小分子三聚氰氯对酰氯化的氧化石墨烯改性,制备石墨烯无机-有机功能化载体,当载体完全氨基化之后,氨基活性位点为PEG的改性提供了支撑点,采用4-4’-二苯甲烷二异氰酸酯改性使得PEG端位带有活性氰酸跟,活性氰酸跟与氨基化的载体聚合制备一体化的石墨烯功能化复合PEG相变材料。获得材料的相变焓损失率低至5.3%,导热率提高了69.5%,热分解温度提高了50℃,在70℃、90℃和110℃分别30min内没有渗漏现象发生。石墨烯凝胶复合PEG相变材料和石墨烯功能化复合PEG相变材料的制备,实现了高导热率、抗渗漏及热稳定性一体化的PEG复合相变材料。
[Abstract]:Phase change energy storage material is an important part of new energy materials. As an advanced energy storage material, phase change will absorb or release phase change latent heat. Unstable energy is stored to solve the problem of time and space mismatch of energy use, but also to improve solar, wind, geothermal energy. The best candidate for energy storage management, such as industrial waste heat, in improving energy efficiency. Polyethylene glycol (PEG) phase change material is an important branch of the research field of new organic phase change materials. PEG has close to the suitable phase transition temperature of human body. The phase change materials with high latent heat and corrosion resistance are suitable for low temperature. The temperature can be designed by molecular weight. However, as phase change material, PEG is faced with the following shortcomings: low thermal conductivity, easy leakage during phase transition, and poor thermal stability. The application value of PEG phase change material is seriously hindered, but PEG as phase change material is faced with the following shortcomings: low thermal conductivity, easy leakage of phase transition process and poor thermal stability. The application value of PEG phase change material has been seriously hindered. In this paper, graphene oxide graphene oxide oxide is prepared by Hummers method. Three-dimensional graphene gel composite PEG phase change material was prepared by one-step hydrothermal method. Vitamin C was used as ascorbic acid. As a reducing agent, this three-dimensional network structure not only provides a heat conduction channel for PEG heat transfer, but also provides a support carrier for solving the leakage of PEG, with the increase of reduction degree. With the reduction of graphene oxide lamellar defects, the thermal physicochemical properties of graphene can be achieved. Compared with pure PEG, the phase change enthalpy loss rate of PEG phase change material is less than 1%. The thermal conductivity was increased by 61.7% and the PEG content could reach 99.3.After 30 min of constant temperature at 70 鈩，
本文编号：1427023
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/1427023.html
