低熔点蜡微胶囊相变材料的研究

STUDY ON THE MICROENCAPSULATED LOW MELTING WAX PHASE CHANGE MATERIALS

以尿素、甲醛、低熔点蜡为原料，采用原位聚合法制备微胶囊相变材料。采用SEM，DSC，FT—IR测试仪器分,NN定微胶囊表面形态、热性能、化学成分；采用激光粒径分布仪测定微胶囊的平均粒径及粒径分布；讨论了微胶囊粒径的影响因素。实验结果表明，当尿素-甲醛预聚体与低熔点蜡质量比为2：1时，采用Span60和Tween60质量比为6：4的复合乳化剂，在乳化搅拌速度13000r/min下乳化8min，缓慢分批加入NH4C催化剂，控制终点pH值为1．5～2．0，在60℃下反应4h，升温到90℃并恒温1h可以得到平均粒径20μm左右、粒径分布在10～30μm的球形微胶囊。DSC分析结果显示微胶囊熔点为35．14℃，潜热为104．19J／g。

Microencapsulated phase change materials were prepared by in-situ polymerization using urea,formaldehyde and wax with low melting point as raw materials. The surface morphology, chemical constitution and thermal property were investigated by SEM,FT-IR,and DSC techniques. The average microcapsule size and size distributions were measured and the factor affected microcapsule size was discussed. Results showed that ball microcapsules having average size of 20 μm and size distributions in the range of 10 30 μm could be prepared under the conditions of a mass ratio of urea-formaldehyde resin to low-melting wax of 2, emulsifying with compound emulsifier（Span60 ： Tween60 = 6 ： 4） and stirring at 1 300 r/min for 8 min,batch dropping NH4Cl catalyst slowly to control the final pH in the range of 1.5-2.0,taking reaction at 60 ℃ for 4 h,then raising the temperature to 90 ℃ for 1 h. DSC results indicated the melting point and latent heat of the obtained microcapsules were 35. 14 ℃ and 104.19 J/g,respectively.