Cross-Linked, Monodisperse, Micron-Sized Polystyrene Particles by Two-Stage Dispersion Polymerization
Cross-Linked, Monodisperse, Micron-Sized Polystyrene Particles by Two-Stage Dispersion Polymerization
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DOI：
10.1021/ma050992z
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发表时间：
2005-08
期刊：
影响因子：
5.5
通讯作者：
Jingjing Song;M. Winnik
中科院分区：
文献类型：
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作者：
Jingjing Song;M. Winnik
众所周知，交联剂如二乙烯基苯（DVB）干扰苯乙烯在乙醇中的分散聚合，该反应在聚合物稳定剂如聚（乙烯基吡咯烷酮）存在下进行。少量的DVB使粒度分布变宽并导致不规则颗粒，而适量的DVB导致凝结。我们报道，如果延迟交联剂的添加直到反应的成核阶段结束之后（例如，在小于5%的单体转化率下）。以这种方式，可以获得含有1重量%的乙二醇二甲基丙烯酸酯（EGDMA）作为交联剂的单分散聚苯乙烯颗粒。如果交联剂在反应中过早消耗，则会出现第二组问题，这可能是因为早期的网络形成限制了生长颗粒的溶胀性。这些问题可以通过在12小时内向反应中加入DVB或通过连续加入EGDMA来克服。
It is well-known that cross-linking agents such as divinylbenzene (DVB) interfere with the dispersion polymerization of styrene in ethanol, a reaction carried out in the presence of polymeric stabilizers such as poly(vinylpyrrolidone). Small amounts of DVB broaden the particle size distribution and lead to irregular particles, whereas modest amounts lead to coagulation. We report that many of these problems can be avoided if one delays the addition of the cross-linking agent until after the end of the nucleation stage of the reaction (e.g., at less than 5% monomer conversion). In this way one can obtain monodisperse polystyrene particles containing 1 wt % ethylene glycol dimethacrylate (EGDMA) as a cross-linker. A second set of problems arises if the cross-linking agent is consumed too early in the reaction, presumably because early network formation limits the swellability of the growing particles. These problems can be overcome by feeding DVB into the reaction over 12 h or by adding EGDMA in successive ...