界面聚合聚脲微胶囊相变材料的制备及性能研究
发布时间：2018-04-22 04:03
本文选题：相变材料 + 微胶囊 ； 参考：《西安工程大学》2015年硕士论文
【摘要】：聚脲微胶囊相变材料由于囊壁中不含有甲醛等有害成分而受到越来越多研究人员的关注,但传统的聚脲囊壁大多都是采用芳香族二元异氰酸酯和脂肪族二元伯胺反应制备的,由于芳香族异氰酸酯与脂肪族伯胺之间的反应速率非常快且形成的聚脲囊壁为二元线性结构,因而所形成的囊壁热稳定性和致密性较差,使其应用受到很大限制。本文通过选用反应速率相对较小的脂肪族二异氰酸酯与制备三元网状结构囊壁两种途径相结合制备了系列高致密性微胶囊相变材料。分别采用光学显微镜、扫描电镜(SEM)、差式扫描量热仪(DSC)、红外光谱(FTIR)和热重分析仪(TGA)对所制备微胶囊相变材料的表面形貌、储热性能、化学结构和热稳定性进行了研究和分析。一方面,以硬脂酸丁酯为芯材,苯乙烯马来酸酐共聚物(SMA)为乳化剂,以异佛尔酮二异氰酸酯(IPDI)和二乙烯三胺(DETA)聚合形成的聚脲树脂为壁材制备微胶囊相变材料,并探讨了在反应体系中加入单体2,4甲苯-二异氰酸酯(TDI)后对所制备微胶囊的表面形貌和热稳定性等性能的影响。结果表明,采用SMA作为乳化剂可以明显地改善微胶囊的团聚现象,且在较少用量和较短的时间内便可获得良好的乳化效果。SEM分析表明,所制备微胶囊颗粒大小均一,呈球形分布,表面凹陷现象严重,加入TDI后可使表面凹陷现象得到改善。DSC分析表明,所制备微胶囊的熔融温度为29.8℃,熔融热焓为89.5J·g㧟1,储热性能良好,结晶曲线出现双放热峰,过冷现象明显。TG结果显示,当芯材壁材比为3:1,分别以IPDI和以IPDI/TDI混合物为异氰酸酯时,所制备微胶囊的耐热温度分别为207℃和227℃。随着芯材壁材比的降低、TDI用量的增大、搅拌转速的提高,微胶囊的耐热稳定性提高。另一方面,采用三官能度的丙三醇对所制备的聚脲囊壁进行改性,制备了具有三元网状结构囊壁的致密性优良的微胶囊相变材料,研究了丙三醇加入方式和丙三醇与DETA质量比对微胶囊表面形貌和热稳定性等性能的影响。SEM结果表明,丙三醇的加入使得所制备微胶囊的表面凹陷情况得到了明显地改善,且丙三醇的用量越高,表面凹陷越少。丙三醇的加入方式对所制备微胶囊的热稳定性具有一定的影响,当DETA与丙三醇先后加入时微胶囊的热稳定性比两者同时加入时要高。TG分析表明,加入丙三醇后所制备的三元网状结构囊壁微胶囊具有良好的热稳定性和致密性,其耐热温度由未改性时的227℃提高至240℃。
[Abstract]:Polyurea microencapsulated phase change materials have attracted more and more attention due to the absence of formaldehyde and other harmful components in the capsule wall. However, most of the traditional polyurea capsule walls are prepared by the reaction of aromatic diisocyanate and aliphatic binary primary amine. Because the reaction rate between aromatic isocyanate and aliphatic primary amine is very fast and the polyurea cyst wall is of binary linear structure, the thermal stability and compactness of the formed polyurea cyst wall are poor, which limits its application. In this paper, a series of phase change materials with high density microcapsules were prepared by combining aliphatic diisocyanate with ternary reticular structure. The surface morphology, thermal storage property, chemical structure and thermal stability of the microencapsulated phase change materials were studied by optical microscope, scanning electron microscope (SEM), differential scanning calorimeter (DSC), FTIR (FTIR) and thermogravimetric analyzer (TGA). On the one hand, using butyl stearate as core material, styrene maleic anhydride copolymer (SMA) as emulsifier, polyurea resin polymerized with isophorone diisocyanate (IPDIA) and diethylenetriamine (DETAA) as wall material, microencapsulated phase change materials were prepared. The effects of the addition of monomer 2O4 toluene-diisocyanate (TDI) into the reaction system on the surface morphology and thermal stability of the microcapsules were investigated. The results showed that the agglomeration of microcapsules could be obviously improved by using SMA as emulsifier, and a good emulsifying effect could be obtained in less dosage and shorter time. The results show that the melting temperature of the microcapsules is 29.8 鈩，
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