氧化石墨烯改性石蜡相变微胶囊的制备与性能研究

发布时间：2018-01-03 15:31

本文关键词：氧化石墨烯改性石蜡相变微胶囊的制备与性能研究　出处：《西南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：能源短缺问题随着全球经济的高速发展日趋突出。相变材料能在其相变过程中吸收和释放相变潜热,从而达到存储和释放能量的效果,是目前缓解能源短缺问题的研究重点之一。将相变材料微胶囊化能够解决相变材料在相变过程中出现的渗漏、腐蚀、相容等问题。目前,相变微胶囊(Microencapsulated phase change materials,MEPCMs)多采用聚合物为壁材,这种相变微胶囊存在导热性能不佳,机械性能差,芯材容易渗漏,包覆率不高等缺陷。石墨烯在导热、阻隔、强度等方面具有优异的性能,作为制备石墨烯的前驱体,氧化石墨烯(Graphene oxide,GO)由于疏水表面带有丰富的亲水性含氧官能团,使其与聚合物有较好的相容性,并且具有两亲性能够稳定皮克林乳液。本论文主要内容包括:(1)在预聚体制备过程将GO引入到密胺树脂(Melamine-formaldehyde resin,MF)预聚体中,再通过原位聚合法制备GO改性MF壁材的MEPCMs;适量GO能够提高MEPCMs的机械性能,但是过量GO会导致MEPCMs的机械性能下降,并使包覆性能下降明显;添加GO能提高MEPCMs的导热性能,当GO分散液的浓度为3.0mg/m L时,热导率增加65.0%;(2)利用GO的两亲性,通过乳化作用将GO引入到石蜡乳滴表面,通过原位聚合法制备以石蜡为芯材,MF为壁材,GO分布在壁材及芯材界面作为额外防渗层的MEPCMs;GO的添加能够提升MEPCMs的防渗性能,当GO分散液的浓度为0.5mg/m L时,MEPCMs的包覆率为93.89wt%,此时,渗漏率较未改性的MEPCMs降低了93.1%;(3)利用GO的两亲性乳化得到GO包覆石蜡的MEPCMs,再通过化学还原得到具有石蜡@还原氧化石墨烯核壳结构的MEPCMs,并热压成具有隔离结构的导热定形相变材料;制备得到的石蜡@还原氧化石墨烯MEPCMs具有明显的核壳结构;壁材含量仅为0.34wt%;测试得到MEPCMs及导热定形相变材料的热导率分别由石蜡的0.125W/(m·K)提高到0.351和0.418W/(m·K)。
[Abstract]:With the rapid development of the global economy, the problem of energy shortage is becoming more and more prominent. Phase change materials can absorb and release latent heat of phase change in the process of phase transition, so as to achieve the effect of energy storage and release. The microencapsulation of phase change materials can solve the leakage, corrosion, compatibility of phase change materials in the process of phase change. At present, the microencapsulation of phase change materials can solve the problems of leakage, corrosion, compatibility and so on. Phase change microencapsulated phase change MEPCMswere mostly made of polymer. The phase change microcapsules have some defects such as poor thermal conductivity, poor mechanical properties, easy leakage of core materials and low coating rate. Graphene has excellent thermal conductivity, barrier and strength. As the precursor of graphene oxide, graphene oxide has good compatibility with polymer due to its abundant hydrophilic oxygen-containing functional groups on the hydrophobic surface. And the amphiphilic property can stabilize the Pickering emulsion. The main contents of this thesis include: 1) introducing go into the melamine resin during the preparation of prepolymer. Melamine-formaldehyde resin. The MEPCMsof MF wall materials modified by go were prepared by in-situ polymerization in the prepolymer. Go can improve the mechanical properties of MEPCMs, but excessive go can lead to the decrease of mechanical properties of MEPCMs and the obvious decrease of coating performance. The thermal conductivity of MEPCMs was improved by adding go. When the concentration of go dispersion was 3.0 mg / mL, the thermal conductivity increased 65.0%. (2) by using the amphiphilic property of go, go was introduced into the surface of paraffin wax emulsion by emulsification, and the wax as core material and MF as wall material were prepared by in-situ polymerization. Go is distributed in MEPCMsof wall material and core material interface as extra impervious layer. Go addition can improve the anti-seepage performance of MEPCMs. When the concentration of go dispersion is 0.5 mg / mL, the encapsulation rate of MEPCMs is 93.89 wts. at this time. The leakage rate was lower than that of unmodified MEPCMs. MEPCMsof go coated paraffin were obtained by amphiphilic emulsification of go, and MEPCMs with paraffin @ reductive graphene core-shell structure was obtained by chemical reduction. The heat conduction phase change material with isolation structure is formed by hot pressing. The prepared paraffin @ reductive graphene MEPCMs has obvious core-shell structure. The content of wall material is only 0.34 wt. The results show that the thermal conductivities of MEPCMs and heat-conducting phase change materials are increased from 0.125 W / m 路K of paraffin to 0.351 and 0.418 W / m 路K ~ (-1) of paraffin, respectively.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34

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