分散聚合法制备窄分子量分布的聚苯乙烯微球

Preparation of Polystyrene Microspheres with Narrow Molecular Weight Distribution by Dispersion Polymerization

以无水乙醇为反应介质,以聚乙烯吡咯烷酮(PVP)为分散剂,偶氮二异丁腈(AIBN)为引发剂,采用分散聚合法制备分子量分布较窄的聚苯乙烯(PS)微球。研究了反应温度及反应时间、引发剂浓度和单体浓度对苯乙烯转化率和PS分子量分布的影响,采用SEM、GPC、FT-IR和TG对产物的形貌、分子结构和性能等进行了表征。结果表明:单体浓度为20%,引发剂用量为单体总量的0.7%,75℃下反应13h后,聚合反应的单体转化率可达87.8%,所制得的PS球形度较好,重均分子量为16.6万,分子量分布1.21,且具有优异的热稳定性。

Polystyrene （PS） particles with a narrow molecular weight distribution were synthesized by dispersion polymerization in alcohol, using polyvinylpyrrolidone （PVP） as dispersant and azobisisobutyronitriie （AIBN） as initiator. Influences of reaction tempreture, reaction time, initiator concentration and monomer concentration on conversion of styrene and molecular weight distribution of PS were researched. Furthermore the morphology, molecular structure, and properties of the PS particles were characterized by scanning electron microscope （SEM）, gel permeation chromatography （GPC）, fourier transform infrared spectrum （FT-IR）, and thermogravimetry （TG）. Results show that the monomer conversion of styrene is up to 87.8%, when the monomer concentration of styrene is 20%, the dosage of initiator is 0.7%, reaction temperature is 75~C, and reaction time is 13h. Under this condition, the spherical PS particles prepared have a good sphericity, a high molecular weight （1.66 X 105）, and a narrow molecular weight distribution （1.21）.