壁材交联对相变微胶囊的性能调控

Performance regulation of phase change microcapsules by cross-linking of wall material

为探讨壁材组成对相变微胶囊性能的调控作用,选用固液混合石蜡为芯材,甲基丙烯酸甲酯为壁材,利用悬浮聚合法制备相变材料微胶囊。加入季戊四醇四丙烯酸酯和甲基丙烯酸烯丙酯作为交联剂,与甲基丙烯酸甲酯进行交联共聚,得到不同壁材组成的相变微胶囊,进而实现对微胶囊性能的调控。扫描电镜(SEM)结果表明,交联剂的加入能够有效提高相变微胶囊的规整性和表面平滑度,并明显改善粒径分布的均匀程度;热失重(TG)和差热扫描量热(DSC)分析表明,交联剂可明显降低微胶囊在高温时的失重分解速率,扩大分解温度范围,增强壁材的稳定性,提高壁材对石蜡的包覆效率。与未加入交联剂的微胶囊相比,相变焓降低。当加入1.0 g季戊四醇四丙烯酸酯时,所得微胶囊有很好的分散性,呈规则球形,表面光滑细致,粒径为1.0~1.5μm;热稳定性较好,可耐155℃高温;相变焓最高值为29.643 J/g。

In order to investigate the effect of wall material composition on the performance of phase change microcapsules, a mixture of solid and liquid paraffin is used as the core material and methyl methacrylate as the wall material to prepare phase change material microcapsules by suspension polymerization method. Pentaerythritol tetraacrylate and allyl methacwlate are crosslinked with methyl methacrylate to obtain phase change microcapsules with different wall materials, and then to achieve the regu- lation of microcapsule performance. The results of scanning electron microscopy （SEM） show that the addition of crosslinking agents can effectively improve the regularity and surface smoothness of phase change microcapsules, as well as the uniformity of particle size distribution. The results of thermogravi- metric analysis （TG） and differential scanning calorimetry （DSC） analysis show that the crosslinking agents can significantly reduce the mass loss rate of the microcapsules at high temperature, increase the decomposition temperature range, enhance the stability of the wall material and improve the coat- ing efficiency of the wall material. Compared with the untreated microcapsules, the phase change en- thalpy decreased. When adding 1.0 g pentaerythritol tetraacrylate, the obtained microcapsules have good dispersibility, regular spherical shape, smooth surface, particle size of 1.0-1,5 μm, good thermal stability, can withstand 155 ℃ high temperature, and the maximum enthalpy of phase change is 29.643 J/g.