微波聚合制备单分散、超细聚甲基丙烯酸甲酯微球  

Preparation of Monodisperse Superfine PMMA Particles by Microwave Emulsifier-Free Polymerization

作　　者：包建军[1] 张爱民[1] 

机构地区：[1]四川大学高分子研究所高分子材料工程国家重点实验室,四川成都610065

出　　处：《功能高分子学报》2003年第1期59-64,共6页Journal of Functional Polymers

基　　金：国家自然科学基金重点项目(20034006);国家自然科学基金面上项目(50203006)资助

摘　　要：　在微波辐照下,通过甲基丙烯酸甲酯(MMA)的无乳化剂乳液聚合,制备出粒径单分散、超细聚甲基丙烯酸甲酯(PMMA)微球。微波显著缩短聚合诱导期,加快聚合反应,其部分原因是微波加快引发剂过硫酸钾(KPS)的分解。实验证明微波辐照下KPS的表观分解活化能(ED)由128.3kJ/mol降低到106.0kJ/mol。单体浓度是影响PMMA乳液粒子尺寸的主要因素,在[MMA]小于0.3mol/L时,平均粒径随单体浓度提高而线形增加;[MMA]为0.3～1.0mol/L时,平均粒径稳定在约200nm;之后随单体浓度进一步增加,乳液稳定性变差。引发剂浓度增加对平均粒径影响较小,但增大引发剂浓度可显著降低粒径分散度。选取[MMA]为0.23～0.3mol/L、[KPS]为3×10-3～6×10-3mol/L可以得到粒径200nm的单分散微球。以丙酮/水(体积比1/3)为反应介质,可制备出数均粒径45nm的PMMA纳米粒子。在体系中加入3.5×10-3mol/L的Cu2+,可制备出数均粒径67nm、单分散的PMMA纳米粒子。Emulsifierfree emulsion polymerization of MMA was carried out using microwave irradiation. Superfine and monodisperse PMMA microparticles were obtained. Microwave irradiation could notably promote the polymerization reaction. This effect was ascribed partially to the speeding of initiator (KPS) decomposition by microwave. The experiment results revealed that the apparent active energy of KPS decomposition (Ed) decreased from 128.3 kJ/mol to 106.0 kJ/mol undergoing the microwave irradiation. The average particle size of prepared PMMA latices was mainly controlled by MMA concentration. The average particle size increased linearly from 103 to 215 nm when MMA concentration increased from 0 to 0.3 mol/L and maintained almost constantly in MMA concentration ranged from 0.3 to 1.0 mol/L. This result could be explained by the rapid coagulation nucleation procedure induced by microwave. When the MMA amount maintained at 0.3 mol/L, the KPS concentration showed no effect on the average particle size. But when increasing the KPS concentration from 0.1×10-3 to 7×10-3 mol/L, the dispersity of particle size could be dramatically decreased. Using acetone-water mixture (volume ratio 1:3) as reaction medium could decrease the PMMA particle size to 45 nm. By adding 3.5×10-3 mol/L Cu2+, monodisperse PMMA nanoparticles with the average particle size 67 nm could be prepared.

关 键 词：微波 无乳化剂乳液聚合 聚甲基丙烯酸甲酯 超细微球 

分 类 号：O63[理学—高分子化学]