Effect of homogeneity of methanol/water/monomer mixture on the mode of polymerization of MMA: Soap-free emulsion polymerization versus dispersion polymerization
Effect of homogeneity of methanol/water/monomer mixture on the mode of polymerization of MMA: Soap-free emulsion polymerization versus dispersion polymerization
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DOI：
10.1016/j.polymer.2009.12.038
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发表时间：
2010-03-02
期刊：
影响因子：
4.6
通讯作者：
Choe, Soonja
中科院分区：
文献类型：
--
作者：
Kim, Gijung;Lim, Samuel;Choe, Soonja
在水介质中加入不同量的甲醇，进行了甲基丙烯酸甲酯（MMA）的无皂乳液聚合。随着甲醇含量的增加，聚合混合物（甲醇/水/单体）的相由多相状态变为均相状态，并在30 wt%甲醇时发生转变。为了确定非均相和均相混合物中的聚合机理，分析了制备的PMMA颗粒的性能，考察了甲醇含量对1 h转化率、引发剂浓度和聚合温度的影响。在0 ~ 20 wt%甲醇的非均相混合物中，聚合产物和聚合行为与无皂乳液聚合的典型产物和聚合行为相似。另一方面，聚合产物的特性与在40-60 wt%甲醇的均相混合物下通常得到的分散聚合相似。因此，水甲醇混合物的均匀性可以是决定无皂乳液和分散聚合之间的聚合模式的关键因素。(C) 2010 Elsevier Ltd.版权所有。
The soap-free emulsion polymerization of methyl methacrylate (MMA) was carried out with varying amount of methanol in the aqueous medium. As methanol content increased, the phase of polymerization mixture (methanol/water/monomer) changed from heterogeneous to homogeneous state and the transition occurred at 30 wt% methanol. In order to identify the mechanism of the polymerization in heterogeneous and homogeneous mixture, the properties of the prepared PMMA particles were analyzed in terms of the effects of methanol content on the conversion at 1 h, initiator concentration and polymerization temperature. With the heterogeneous mixture in the range of 0-20 wt% methanol, the polymerization product and polymerization behavior resembled those typically observed in the soap-free emulsion polymerization. On the other hand, the characteristics of the polymerization products were similar to those typically obtained in the dispersion polymerization under the homogeneous mixture ranging 40-60 wt% methanol. Thus, the homogeneity in the aqueous methanol mixture can be a critical factor in determining the polymerization modes between the soap-free emulsion and dispersion polymerization. (C) 2010 Elsevier Ltd. All rights reserved.