【作者】 王丽丽；

【导师】 赵天波；

【作者基本信息】 北京理工大学 ， 化学， 2016， 硕士

【摘要】 石蜡在相变过程中会吸收或放出大量热量,是一种优良储能材料。然而在吸热过程中会由固态转化为液态,在复合材料中容易流淌出来,因此限制了石蜡作为相变储能材料的应用。本文采用两种方法来改善石蜡高温流淌的现象。一是将石蜡微胶囊化,可以解决石蜡在固-液相变时使用不便的缺点。另一种方法则是将石蜡生成聚集体,成为半流体防止其高温时流淌。本论文通过悬浮聚合法,以交联型聚苯乙烯-二乙烯基苯共聚物为壁材,熔点54℃的石蜡为芯材,采用聚乙烯吡咯烷酮为分散剂,制备了石蜡/聚苯乙烯微胶囊,并采用扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FTIR)、示差扫描量热仪(DSC)、热重分析仪(TG)、激光粒度仪等对制备的石蜡/聚苯乙烯微胶囊进行表征。通过改变分散剂的种类和用量制备了一系列粒径、形貌和芯材含量不同的微胶囊;确定了单体/交联剂的最佳用量为8:1,并发现调整交联剂的加入方式可以改善微胶囊的表观形貌;共聚单体MMA的加入对微胶囊性能没有明显的改善;单体与石蜡的投料比对微胶囊的储热性能影响较大,当单体/石蜡质量比为5:2时,微胶囊的相变焓为108.5J/g,芯材含量为69.2%。使用锂基、铝基和脲基三种稠化剂与石蜡生成聚集体,用扫描电子显微镜观察微观形貌,用滴点仪测定滴点。结果表明,使用聚脲稠化剂生成石蜡聚集体的效果最好;在稠化过程中加入部分基础油的更易生成聚集体。更多还原

【Abstract】 In recent years, thermal energy storage systems can provide the potential to attain energy savings, which reduce the environmental impact related to energy use. Phase changed materials(PCMs) which can absorb or release large amounts of heat during their phase transition are ―latent‖ energy storage materials. However, leakage of the melted PCMs during the phase change process and reactivity with the outside environment have limited their application. This paper adopts two methods to improve leakage of the melted PCMs. Firstly, encapsulation of PCMs can overcome the above problems effectively. Secondly, the principles of the preparation of the grease have been taken example. Using thickeners viscosify paraffin and make its formation semi-fluid.The microencapsules of paraffin melting point at 54℃as a novel phase change material(PCM) using styrene(St)-divinybenzene(DVB) co-polymer as shell is prepared by suspension-like polymerization. The surface morphologies, particle size distributions, phase change properties,and thermal stabilities of the microcapsules were investigated using FTIR, SEM, Laser Particle Size Analyzer, DSC, TGA, respectively. A series of different partical sizes and morphologies of paraffin / polystyrene-divinylbenzene microcapsules were prepared by using different kind and amount dispersing agent. The best dosage of polystyrene/divinylbenzene was 8:1.When the cross-linker DVB was added after 2h of polymerization, the obtained P(St-DVB) microencapsules exhibited good sphericity meanwhile display little influence on the phase change properties and thermal stabilities of the microcapsules. The amount of 54 # paraffin encapsulated was 69.2% when the ratio of paraffin / styrene was 5:2. The temperature of thermal resistant of microencapsules was approximately 230℃, which was higher 30℃ than that of pure 54 paraffin.Using lithium base, aluminum base and urea based three kinds of thickeners thickening on paraffin wax. The surface morphologies and dropping point were investigated using SEM and drop point meter, respectively. Results indicated that using urea based thickeners thickening on paraffin wax was best effect.更多还原