分散聚合法制备PVP微球的研究

以N-乙烯基吡咯烷酮(NVP)为初始单体,乙酸乙酯为分散介质,采用分散聚合法制备了分散性能良好、粒径为3～4μm的聚乙烯基吡咯烷酮(PVP)微球.考察了单体、分散剂及引发剂浓度对PVP微球的粒径、单体转化率及分子量的影响,并对PVP的结构和性能进行研究.结果表明,单体浓度增加,PVP微球粒径和分子量增大,单体转化率升高;分散剂浓度增加,PVP微球粒径变小,分子量增大,单体转化率升高;引发剂浓度增加,PVP微球粒径变大,分子量减小,单体转化率升高.与溶液聚合法相比,分散聚合法制备的PVP分子量较小且具有一定的结晶性.

PREPARATION OF POLYVINYLPYRROLIDONE MICRO SPHERES BY DISPERSION POLYMERIZATION

This reports on the preparation of polyvinylpyrrolidone(PVP)micro spheres in ethyl acetate by dispersion polymerization with N-vinylpyrrolidone(NVP)as initial monomer,P(NVP-co-VAc)as dispersant,and AIBN as initiator.The influences of monomer concentration,dispersant concentration and initiator concentration on the size of PVP micro spheres as well as the monomer conversion rate were studied.The structure and properties of PVP micro spheres were analyzed.The results show that the prepared PVP micro spheres have a mean diameter of 3～4 μm.As the concentration of NVP increased,the micro sphere size and the molecular weight of the PVP increased and the monomer conversion rate also increased.As the concentration of P(NVP-co-VAc)increased,the size of micro spheres decreased,and the molecular weight of the PVP and the monomer conversion rate increased.As the concentration of AIBN increased,the size of micro spheres and the monomer conversion increased,the molecular weight of the PVP is also increased.The PVP prepared by dispersion polymerization has crystal structure and its molecular weight is low as compared to those prepared by solution polymerization.