粒径可控的高比表面积交联聚乙烯醇微球的制备

Preparation of Poly(vinyl acetate)Cross-Linked Microspheres with Controllable Size and High Specific Surface Area

以醋酸乙烯酯(VAc)为单体,二乙烯基苯(DVB)为交联剂,通过悬浮聚合制备了一系列不同粒径(0.1~0.5mm)的交联聚醋酸乙烯微球,经过醇解,制得了交联聚乙烯醇微球。研究发现,搅拌速度对微球粒径大小影响较大,重点考察了搅拌速度对平均粒径和粒径分布的影响,实验结果表明,随着转速的逐步提升,微球的平均粒径明显减小,粒径分布变窄。通过在聚合过程中引入适当的致孔剂,获得高比表面积的微球,最高可达494.1m2/g,探讨了致孔剂种类和交联剂用量对比表面积的影响。结果表明,当增加交联剂的用量或者加入与共聚物溶度参数相近的致孔剂时,微球的比表面积显著增大。

By using vinyl acetate （VAc） as monomer and divinyl benzene （DVB） as crosslinking agent, crosslinked poly （vinyl acetate） microspheres with different sizes （0.1-0.5 mm） were prepared via suspension polymerization. After alcoholysis, cross-linked poly （vinyl alcohol） microspheres can be obtained. We focused on the effect of rotational speed on the average size and size distribution of microspheres. The experimental results show a trend that, as the stirring speed increasing, the average size of microspheres decreases and the uniformity of final size distribution increases obviously, the results can be explained by decrease of the coalescence between droplets under a higher stirring speed. On this basis, to obtain high surface area microspheres, appropriated porogens were added in the polymerization process, with the largest up to 494.1 m2/g, the effect of porogen type and divinylbenzene （DVB） content on specific surface area was investigated in order to obtain microspheres with large specific surface areas. The results indicate that the specific surface area increases significantly while the DVB content is increased or a porogen with solubility parameter similar to copolymer is added.