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通过实验研究确定制备稳定的微胶囊相变悬浮液必须采用的最优化表面活性剂添加量和悬浮液pH值。采用全功能稳定性分析仪TURBISCAN LAb研究表面活性剂十二烷基硫酸钠(SDS)添加量和悬浮液pH值对物理稳定性的影响。结果表明,当SDS质量分数太低,即颗粒表面改性不彻底时,稳定性较差;质量分数太高,容易形成表面活性剂胶束沉淀,并同时加速相变微胶囊颗粒上浮,破坏微胶囊相变悬浮液的稳定性,在选定的SDS质量分数范围内,最佳质量分数为0.2%~0.4%;pH值低于7时,溶液颗粒分散性提高不明显,并且出现加快分层现象;pH值过高时,溶液中OH-过多,压缩双电层厚度,减弱颗粒分散性,溶液稳定性提高受到抑制,在选定的pH值范围内,密胺树脂壳材的悬浮液最佳pH值为8。抑制悬浮液的分层和团聚现象对于其在传热和储热中的应用有重要意义,研究结果给制备稳定的悬浮液提供了可靠的依据。
Through experimental study, the optimal amount of surfactant and suspension pH value must be determined to prepare stable microcapsule phase change suspension. The TURBISCAN LAb, a fully functional stability analyzer, was used to investigate the effect of the surfactant sodium dodecyl sulfate (SDS) and the pH of the suspension on the physical stability. The results show that when the mass fraction of SDS is too low, that is, the particle surface is not completely modified, the stability is poor. When the mass fraction is too high, the surfactant micelles precipitate and the particles of the phase-change microcapsule are accelerated, The stability of capsule phase-change suspension in the range of the selected mass fraction of SDS, the best mass fraction of 0.2% to 0.4%; pH value of less than 7:00, the dispersion of the solution particles is not obvious, and the emergence of accelerated stratification Phenomenon; when the pH value is too high, OH- in the solution is too much, the thickness of the compressed electric double layer is reduced, the dispersibility of the particles is weakened, and the stability of the solution is inhibited. In the selected pH range, the suspension of the melamine resin shell The optimum pH is 8. Inhibition of the delamination and agglomeration of the suspension is of great significance for its application in heat transfer and heat storage, and the results provide a reliable basis for the preparation of a stable suspension.