聚-α-甲基苯乙烯微球固化过程中的密度匹配

Density match during fabrication process of poly (α-methylstyrene) mandrels by microencapsulation

在采用乳液微封装技术制备聚-α-甲基苯乙烯(PAMS)空心微球的双重乳液固化过程中,为研究油包水(W1/O)复合液滴与外水相(W2)之间的密度匹配度对最终PAMS空心微球球形度的影响,理论研究了不同初始外径和油层厚度的复合液滴在不同固化时刻的平均密度;实验测量了W1/O复合液滴在固化过程中的油相质量分数及复合液滴的平均密度。研究结果表明:双重液滴固化过程的关键阶段为油相质量分数从20%增加至60%的过程。在双重乳液固化的关键阶段,当复合液滴与外水相的密度不匹配度由0.004 95g/cm3降低至0.000 02g/cm3时,微球球形偏离度值低于10μm的PAMS微球粒子分数从14.3%提高至93.3%;调节外水相的组分来降低双重乳液与外水相在固化关键阶段的密度不匹配度,可显著提高最终PAMS微球的球形度。

During the curing process of double emulsions for fabricating poly（α-Symbolamethylstyrene）（PAMS） capsules by microencapsulation technology,the match of density between the water in oil compound droplet and the outer water phase is vital to the sphericity of PAMS capsules.To investigate the effects of density mismatch on the sphericity of the resulting PAMS capsules,the densities of compound droplets with different inner diameters and polymer oil layer thicknesses were calculated theoretically and measured experimentally during the curing process.Also,the polymer concentrations of the oil phase in the compound droplets during the curing process were further studied.The results show that,the density mismatch between the compound droplets and the outer water phase can be quantitatively controlled by adjusting the compositions of the outer water phase.The curing stage with the polymer concentration of the oil phase increasing from 20% to 60% is the key phase of the curing process.When the density mismatch between the compound droplets and the outer water phase lowering from 0.004 95 g/cm3 to 0.000 02 g/cm3,the number percentage of PAMS capsules with out of round（OOR） value less than 10 μm in batches can be increased from 14.3% to 93.3%.Thus for the compound droplets with different inner diameters and polymer oil layer thicknesses,the sphericity of the resulting PAMS capsules can be significantly improved,through reducing the density mismatch between the compound droplets and the outer water phase in the key phase of the curing process.