Lee Ki-Chang
Department of Polymer Science and Engineering, School of Nano and Advanced Materials Engineering Research Institute, Gyeongsang National University, Jinju 660-701, Korea.
J Nanosci Nanotechnol. 2013 Sep;13(9):6286-92. doi: 10.1166/jnn.2013.7718.
When polymer particles come into use, especially, for photonic crystal applications, their diameter, dispersivity, and refractive indices become very important. Poly(benzyl methacrylate) is known to be a kind of high refracive materials (n = 1.57) compared to poly(methyl methacrylate) (n = 1.49). Not many work was concerned for surfactant-free emulsion polymerization of benzyl methacrylate or its copolymerization using cationic initiators. Narrowly dispersed cationic poly(BMA-co-MMA) and PBMA latices were synthesized successfully by surfactant-free emulsion polymerization with AIBA. The influences of BMA/MMA ratio, BMA/MMA monomer and initiator concentrations, addition of DVB/EGDMA crosslink agent, and polymerization temperature on the kinetics and on the particle size and molecular weight were studied. Monodisperse cationic charged PBMA and poly(BMA-coMMA) latices with particle diameters varying between 160-494 nm and polymer molecular weights of the order 1.25 x 10(4) to 7.55 x 10(4) g/mol were prepared. The rate of polymerization increased with increasing MMA concentration in BMA/MMA ratio, AIBA concentration, DVB crosslink agent, and polymerization temperature. The particle diameter increased with BMA concentration in BMA/MMA ratio, AIBA concentration, and BMA/MMA monomer concentration. The molecular weight increased with BMA concentration in BMA/MMA ratio and BMA/MMA monomer concentration. The glass transition temperature of the latex copolymers decreased with increasing amount of BMA from 375 K for PMMA to 321 K for PBMA. It was, thus, found that the particle diameter and rate of polymerization as well as the polymer molecular weight for surfactant-free emulsion polymerization of BMA and MMA can be controlled easily by controlling the BMA/MMA ratio, BMA/MMA monomer concentration, AIBA concentration, and polymerization temperature.
当聚合物颗粒投入使用时，尤其是用于光子晶体应用时，它们的直径、分散性和折射率变得非常重要。与聚甲基丙烯酸甲酯（n = 1.49）相比，聚甲基丙烯酸苄酯是一种高折射率材料（n = 1.57）。关于甲基丙烯酸苄酯的无表面活性剂乳液聚合或使用阳离子引发剂的共聚反应，相关研究并不多。通过使用偶氮二异丁脒盐酸盐（AIBA）进行无表面活性剂乳液聚合，成功合成了窄分布的阳离子聚（甲基丙烯酸苄酯 - 共 - 甲基丙烯酸甲酯）和聚甲基丙烯酸苄酯胶乳。研究了甲基丙烯酸苄酯/甲基丙烯酸甲酯（BMA/MMA）比例、BMA/MMA单体和引发剂浓度、二乙烯基苯/乙二醇二甲基丙烯酸酯（DVB/EGDMA）交联剂的添加以及聚合温度对动力学、粒径和分子量的影响。制备了粒径在160 - 494 nm之间变化且聚合物分子量在1.25×10⁴至7.55×10⁴ g/mol量级的单分散阳离子聚甲基丙烯酸苄酯和聚（甲基丙烯酸苄酯 - 共 - 甲基丙烯酸甲酯）胶乳。聚合速率随着BMA/MMA比例中甲基丙烯酸甲酯（MMA）浓度、AIBA浓度、DVB交联剂以及聚合温度的增加而提高。粒径随着BMA/MMA比例中甲基丙烯酸苄酯（BMA）浓度、AIBA浓度以及BMA/MMA单体浓度的增加而增大。分子量随着BMA/MMA比例中BMA浓度以及BMA/MMA单体浓度的增加而增大。胶乳共聚物的玻璃化转变温度随着BMA含量的增加从聚甲基丙烯酸甲酯（PMMA）的375 K降至聚甲基丙烯酸苄酯（PBMA）的321 K。因此，发现通过控制BMA/MMA比例、BMA/MMA单体浓度、AIBA浓度和聚合温度，可以轻松控制BMA和MMA的无表面活性剂乳液聚合的粒径、聚合速率以及聚合物分子量。
