【作者】 段武海；

【导师】 于伟东；

【作者基本信息】 东华大学 ， 纺织材料与纺织品设计， 2007， 硕士

【摘要】 相变蓄能微胶囊是近三十年才发展起来的一项技术。由于相变蓄能微胶囊具有较大的相变热，能进行温度调节，故在许多领域中开始应用。国外对蓄热微胶囊的研究工作主要集中在以蜜胺-甲醛和硅酸钙为壁材，以石蜡烃为芯材的微胶囊技术。国内也有多家科研院所以石蜡为芯材进行包覆。虽然已有很多专利和文章出现，但大多是停留在理论阶段，实际应用很少。本课题是在阅读了大量的参考文献之后，经过细致的甄选，采用新型微胶囊成形方法，以PEG-2000为芯材，聚丙烯腈(PAN)为壳材，利用反相乳液聚合中一个新的发展方向-核壳(种子)聚合原理，制备相变储能微胶囊。并采用扫描电镜(SEM)、普通光学显微镜、热分析(DSC)、热重分析(TG)和激光粒径分析仪等仪器对对微胶囊形状及热性能进行表征。所得的微胶囊粒径分布均匀，表面光滑且致密；具有较好的相变点激发温度和较高的相变能；而且有较高的相变物质填充率。本项课题分为以下三部分：第一部分，相变材料纳胶囊的制备与性能研究；第二部分，相变材料微胶囊过冷现象的预防；第三部分，相变材料微胶囊耐高温性能与表征。这三部分内容密切相关，为最终获得耐高温、减少过冷的相变材料纳胶囊奠定了基础。在相变微胶囊的制备上，选取超声波分散和高速剪切乳化等控制条件，复合制备高相变蓄能微胶囊。本课题中首次尝试使用超声波分散，粒径分布均匀，成囊性能良好，外壁光滑，同时，超声波的空化作用会使得长链高分子部分分解，通过控制空化时间和强度，可以改变相变激发点，为获得特定温度激发点下的相变储能微胶囊提供有效方法。探讨工艺条件对微胶囊粒径及粒径分布的影响；并优化了相变储能为胶囊的成形工艺。经实验表明，无论是何种比例的相变储能微胶囊，提高乳化速度、延长乳化时间、提高乳化剂和引发剂用量、降低相比和芯壁比增加，都会使微胶囊的粒径变小、壁厚变薄、粒径分布变窄；反之，使微胶囊的粒径变大、壁厚增加、粒径分布变宽。上述实测表征和工艺优化实验研究表明：①以PEG-2000为芯材，以聚丙烯腈(PAN)为壳材，通过反相乳液聚合法可以合成性能良好的蓄热微胶囊；②微胶囊表面光洁、大小均匀，制备直径0.2～2μm；③蓄热微胶囊中的PEG-2000含量可达包覆容量为46～78％，储热量为110-150 J／G。微胶囊制备的蓄热调温纺织品应该说已有利用。有用微胶囊和纺丝液共混纺制纤维的尝试，也有用微胶囊进行织物涂层整理的应用，但其相变能是微乎其微的，激发点和热吸收的滞后也是显而易见的。因为微胶囊的填充率≤80％，微胶囊在纤维中或涂层织物的占有率一般≤10％。因此，即使不考虑热传递的损耗，可利用的相变能最多亦只有8％。这远远无法满足人体热耗散的需求。因此如何提高相变材料本身的相变能，即筛选材料；如何增大相变材料填充比和表层材料的热阻；以及如何设计蓄热、调温纺织品的结构，仍有许多基础工作需要进行和尝试。更多还原

【Abstract】 Microencapsulation phase chang materials (PCMs) is a boomingtechnology in the past 30 years and has an extensive application in manyfields because of its relatively large critical heat and temperatureadjustment. Most research work abroad was focused on usingcyanurtriamide-formaldehyde as shell materials and alkanes as corematerials, and so is the civil research. A great deal of patens andpublications can be found about this field, however, the industrialapplications is still kept few.This project was chosen on the basis of a good acknowledgement ofthis field and a new form method of microcapsule was used.polywrhylene glycol (PEG)-2000 was selected as core andpolyacrylonitrile (PAN) as shell. A novel way of phase reversal latexpolymerization—the core-shell polymerization theory was adapted toprepare the energy-stored MicroPCMs in this research. SEM、DSC、TG、Laser Granularmetric Analyzer and Optical Microscope were used tostudy the morphology of microcapsules and characterize thethermo-properties. The resulted microcapsules have even distribution oftheir grain diameters, and smooth surfaces and compact materials, moreover, a good phase change trigger temperature and comparativelyhigh phase change energy and phase change materials filling rate.This project was carried on the main three parts as follow:Ⅰ.prepare the microPCM microcapsule (MicroPCMs) and study theproperties;Ⅱ.prevent the over cold phenomena of microPCMs;Ⅲ.study and characterize the high thermo-resistant properties;These three parts have very close relationship, and settle a basis ofobtaining the ultimate high temperature resistant and less over coldPCMs.During the preparation process of PCM microcapsules, theultrosonic vibration and high-speed cut emulsification were used andtechnological conditions were also studied on the influence to graindiameters and distributions. Whatever the proportion of microcapsules,increase the emulsification speed, prolong emulsification time, increasethe dosage of emulgator and initiator, reduce the phase ratio andcore-shell ratio will result the smaller diameters, thinner shell thicknessand narrower diameter distributions, conversely, will get the oppositeresults.The characterization results and optimal technics trials showed that:1. PEG-2000 as core and PAN as shell by phase reversal latexpolymerization to prepare thermal storage microPCMs with good properties.2. This microPCMs havesmooth surface and even diameter distribution inthe range of 0.2 to 2μm.3. The coating capacity of PEG-2000 is about 46-78% and thermalstorage energy is 110-151J/G.Thermal storage fabrics made from microPCMs have appearedabroad. Some MicroPCMs mixed with filature solution to make fibres orfabrics coated finishing have also been found, but the phase changeenergy is a little, trigger points and hysteresis of thermal activation is alsoobvious. Usually, the filling rate of microPCMs is up to 80% and thecontent proportion of microPCMs in fibers or coatings less than 10%under the consideration that there are no effect on mechanical propertiesof the materials. As a result, the utilized phase change energy is at most8% even without regard to the loss of heat transmission. This level is faraway the demand of human body heat dispersion. For this reason, how toimprove the phase change energy of PCMs or choose materials; how toincrease the filling rate of PCMs and thermoresistance of shell materials;how to design the structures of thermo-storage and temperature sensitivetextiles need to be solved, and lots of basic research and trials need to becarried on.更多还原