EFFECT OF INTERFACIAL PHENOMENA ON THE DEVELOPMENT OF PARTICLE MORPHOLOGY IN A POLYMER LATEX SYSTEM
EFFECT OF INTERFACIAL PHENOMENA ON THE DEVELOPMENT OF PARTICLE MORPHOLOGY IN A POLYMER LATEX SYSTEM
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DOI：
10.1021/ma00013a007
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发表时间：
1991-06-24
期刊：
影响因子：
5.5
通讯作者：
ELASSER, MS
中科院分区：
文献类型：
--
作者：
CHEN, YC;DIMONIE, V;ELASSER, MS
以单分散聚苯乙烯乳胶粒为种子，甲基丙烯酸甲酯为第二阶段单体，在不同种子聚合物/单体重量比下，于70 ℃进行种子间歇乳液聚合。 发现最终的复合胶乳颗粒具有多于一种不均匀形态的混合物。 热力学分析和数学模型推导出的自由能的变化，对应于各种可能的结晶不稳定的形态过程中的种子乳液聚合。 根据实验测得的界面张力，计算了颗粒形态的相对稳定性。 提出了聚合过程中粒子形态变化的机理。 热力学分析表明，在最终胶乳中观察到的混合颗粒形态是由于在聚合的最后阶段与高内粘度相关的受限链流动性。 当复合胶乳样品用甲苯溶胀时，颗粒形态显示出向更有利的形态发展的趋势。
Seeded batch emulsion polymerization was carried out at 70-degrees-C using monodisperse polystyrene latex particles as seed and methyl methacrylate as second-stage monomer at different seed polymer/monomer weight ratios. The final composite latex particles were found to have a mixture of more than one nonuniform morphology. A thermodynamic analysis and a mathematical model were derived to describe the free energy changes corresponding to various possible thermodynamically unstable morphologies during the course of the seeded emulsion polymerization. On the basis of experimentally measured interfacial tensions, the relative stabilities of particle morphologies were calculated. The mechanism of changes in particle morphology during the polymerization is proposed. Thermodynamic analysis suggested that the observed mixed-particle morphology in the final latex is due to restricted chain mobility related to high internal viscosity during the final stage of the polymerization. When the composite latex samples were swollen with toluene, the particle morphology showed a tendency toward a thermodynamically more favorable morphology.