Pedaballi Sireesha, Li Chia-Chen, Song Ya-Jun
Institute of Materials Science and Engineering, Department of Materials & Mineral Resources Engineering, National Taipei University of Technology Taipei 10608 Taiwan
RSC Adv. 2019 Aug 5;9(42):24175-24183. doi: 10.1039/c9ra04740a. eCollection 2019 Aug 2.
Microcapsules are widely applied in coatings; however, there are very few reports on the dispersion of microcapsules in the coating material or the effects of dispersion on their performance. Herein, the efficiency of three types of dispersants bearing distinctive functional groups for the dispersion of concentrated thermochromic microcapsules in a solvent and coating resin is studied. The dispersion properties of 35 wt% thermochromic microcapsules in toluene and in coating resin are investigated by measuring their sedimentation and rheological behavior. Interactions between the dispersant and microcapsules are characterized by Fourier transform infrared spectroscopy in order to identify the dominant dispersion mechanism. The physical quality and thermochromic performance of the coating films are characterized by electron microscopy observations and temperature variation tests. The most effective dispersant for thermochromic microcapsules is determined. Compared to the coating film containing non-dispersed microcapsules, the film with well-dispersed microcapsules shows improved surface flatness, with few or no pores in the microstructure. In addition, the color of the film with well-dispersed thermochromic microcapsules shows faster response to temperature variation, resulting in complete and uniform color transformation.
微胶囊在涂料中有着广泛的应用；然而，关于微胶囊在涂料中的分散情况或分散对其性能的影响的报道却非常少。在此，研究了三种带有不同官能团的分散剂对浓缩热致变色微胶囊在溶剂和涂料树脂中的分散效果。通过测量35 wt%热致变色微胶囊在甲苯和涂料树脂中的沉降和流变行为，研究了其分散性能。利用傅里叶变换红外光谱对分散剂与微胶囊之间的相互作用进行表征，以确定主要的分散机理。通过电子显微镜观察和温度变化测试对涂膜的物理质量和热致变色性能进行表征。确定了对热致变色微胶囊最有效的分散剂。与含有未分散微胶囊的涂膜相比，微胶囊分散良好的涂膜表面平整度有所提高，微观结构中几乎没有或没有孔隙。此外，热致变色微胶囊分散良好的涂膜颜色对温度变化的响应更快，从而实现完全且均匀的颜色转变。
