Electron microscopic observation of uniform macroporous particles. I. Effect of seed latex type and diluent
Electron microscopic observation of uniform macroporous particles. I. Effect of seed latex type and diluent
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DOI：
10.1002/(sici)1097-4628(19990404)71:14
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发表时间：
1999-04
影响因子：
3
通讯作者：
A. Tuncel;M. Tuncel;B. Salih
中科院分区：
文献类型：
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作者：
A. Tuncel;M. Tuncel;B. Salih
采用多步种子聚合法制备了粒径为5-21 μm的大孔聚合物粒子。以粒径在1.9-7.5 μm的聚苯乙烯为种子颗粒，制备了大孔微球。采用分散聚合法，通过改变分散介质的种类和引发剂的浓度，制备了不同粒径和分子量的种子粒子。在大孔粒子的合成中，采用两步溶胀程序。种子胶乳首先被低分子量有机试剂（即，邻苯二甲酸二丁酯，DBP），然后通过包括油相可溶性引发剂（即，过氧化苯甲酰）。最终珠粒中的多孔结构是通过溶胀的种子颗粒内的单体相的聚合来实现的，所述溶胀的种子颗粒包括线性聚苯乙烯和DBP的混合物。再聚合步骤中的引发剂浓度、种子胶乳类型（即，种子胶乳的直径和分子量）、DBP/种子胶乳和单体/种子胶乳的比率进行改变，以获得具有不同平均尺寸和孔结构的均匀聚合物珠粒。通过扫描电子显微镜分析最终珠粒的平均尺寸、尺寸分布和表面形态。通过透射电子显微镜分析珠粒的内部结构。结果表明，随着种子胶乳粒径、DBP/种子胶乳比和单体/种子胶乳比的增加，最终粒子的平均粒径增大。平均孔径随种子胶乳分子量的降低、DBP/种子胶乳比和单体/种子胶乳比的增加而减小。这些趋势是由在再聚合步骤中使用的致孔剂溶液的粘度变化来解释的。© 1999 John Wiley & Sons，Inc.应用聚合物科学杂志71：2271-2290，1999
Uniform and macroporous polymer particles in the size range of 5–21 μm were prepared by a multistep seeded polymerization method. The uniform polystyrene particles in the size range of 1.9–7.5 μm were used as the seed particles in the preparation of macroporous beads. The seed particles with different sizes and molecular weights were produced by dispersion polymerization, by changing the type of dispersion medium and the initiator concentration. In the synthesis of macroporous particles, a two-step swelling procedure was employed. The seed latexes were first swollen by a low molecular-weight organic agent (i.e., dibutyl phthalate, DBP), then by a divinylbenzene–ethylvinylbenzene isomer mixture including an oil phase soluble initiator (i.e., benzoyl peroxide). The porous structure in the final beads was achieved by the polymerization of the monomer phase within the swollen seed particles including a mixture of linear polystyrene and DBP. The initiator concentration in the repolymerization step, the seed latex type (i.e., the diameter and the molecular weight of seed latex), DBP/seed latex, and the monomer/seed latex ratios were changed to achieve uniform polymer beads with different average sizes and pore structures. The average size, the size distribution, and the surface morphology of final beads were analyzed by Scanning Electron Microscopy. The internal structure of the beads were analyzed by Transmission Electron Microscopy. The results indicated that the average size of the final particles increased with increasing the seed latex diameter, DBP/seed latex, and monomer/seed latex ratios. The average pore size decreased with decreasing the molecular weight of the seed latex and increasing the DBP/seed latex and monomer/seed latex ratios. These tendencies were explained by the viscosity change of the porogen solution used in the repolymerization step. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2271–2290, 1999