均匀粒度分布的双壳相变储湿微胶囊制备

分别以正十八烷、甲基丙烯酸甲酯和壳聚糖作为核材料、内壳和外壳,采用细乳液原位聚合法及界面聚合法制备双壳相变储湿微胶囊。通过均匀设计与径向基函数神经网络结合,考察因素(如乳化剂用量、助乳化剂用量、引发剂用量、超声乳化时间和搅拌速度)对双壳相变储湿微胶囊粒度分布的影响,并且对最均匀粒度分布双壳相变储湿微胶囊进行表征与测试。结果表明,当扩展系数为0.55时,径向基函数神经(Radial Basis Function,RBF)网络具有最佳的逼近效果。最均匀粒度分布双壳相变储湿微胶囊的制备工艺参数:乳化剂用量为3.58wt%、助乳化剂用量为0.53wt%、引发剂用量为1.86wt%、超声乳化时间为11.35 min,搅拌速度为632r·min~(-1)。基于上述制备参数,d_(10)为3 352.0nm、d50为4 474.9nm,d_(90)为6 108.4nm,d_(90)-d_(10)实测值为2 756.4nm,实测值与预测值吻合较好,相对误差为2.69%。在相对湿度35%~65%的平衡含湿量为0.0547~0.1259g·g~(-1),相变温度为28.87℃,相变焓为78.45J·g~(-1)。

Preparation of double-shell phase change and humidity storage micro-capsules with uniform particle size distribution

With n-octadecane,methyl methacrylate and chitosan as the core material,inner shell and outside shell respectively,the double-shell phase change and humidity storage micro-capsules were made by in-situ polymerization and emulsion interfacial polymerization method.Combining the uniform design and radial basis function neural net-work,the effect of parameters (i.e.emulsifier amount,co-emulsifier amount,initiator amount,phacoemulsification time and mixing speed)on particle size distribution of double-shell phase change and humidity storage micro-capsules were investigated.In addition,the optimal uniform particle size distribution of double-shell phase change and humid-ity storage micro-capsules were tested and characterized.The results show that radial basis function(RBF)neural network has the best approximation effect when "Spread"is 0.55 .To obtain optimal uniform particle size distribu-tion for double-shell phase change and humidity storage micro-capsules,the preparation parameters are identified as follows:emulsifier amount to be 3.58wt%,co-emulsifier amount to be 0.53wt%,initiator amount to be 1.86wt%, phacoemulsification time to be 11.35 min and mixing speed to be 632 r·min-1 .On the base of the above preparation parameters,d10 is 3352.0 nm,d50 is 4474.9 nm,d90 is 6108.4 nm,and the measured value of d90 -d10 is 2756.4 nm.Therefore,the measured value agrees well with the predictive value (relative error is 2.69%).In the case of relative humidity between 35% and 65%,the equilibrium moisture content is obtained to be between 0.0547 g·g-1 and 0.1259 g · g-1 , phase transition temperature is 28.87℃ and phase change enthalpy is 78.45 J·g-1 .