各向异性导电胶膜用单分散聚苯乙烯微球的合成-材料加工工程专业论文.docxVIP

华中科技大学硕士学位论文 华 中 科 技 大 学 硕 士 学 位 论 文 IV IV 摘 要 本论文以合成各向异性导电胶膜用 PS 微球为目的，介绍了 ACF 在电子封装中 的地位与发展现状，开发了 ACF 制造的核心技术之一－单分散聚苯乙烯微球的制 备技术。 课题以苯乙烯为单体、AIBN 为引发剂、PVP 为稳定剂，通过研究分散聚合过 程中单体添加方式、稳定剂用量、反应介质等因素对聚苯乙烯微球粒径以及粒径分 布的影响，成功地合成了平均粒径为 2-5?m，分散系数小于 5%的单分散聚苯乙烯 微球。 在研究过程中发现：当单体为一次性加入时，所得微球更为均匀；随着稳定剂 PVP 用量的增加，所得微球粒径减小，但分散性有所提高，这与相同浓度下稳定剂 分子量增大的影响是一致的；在乙醇/水、乙醇/甲醛以及异丙醇/甲苯溶液中进行的 分散聚合表明，当溶液的溶度参数减小时，微球粒径变大，分布变宽；此外，交联 剂 DVB 的加入虽然可以大大提高微球的玻璃化温度，但对微球形貌及分布却有不 良影响。 本课题还分别对分散聚合过程中线型、交联苯乙烯自由基聚合的机理进行了详 细分析，总结出了分散聚合中的四个基元反应，即链引发、链增长、链转移和链终 止对实验结果的影响。 关键词：分散聚合，单分散，微球，苯乙烯，反应介质，自由基聚合 PAGE VI PAGE VI Abstract The intention of this thesis was to prepare monodisperse polystyrene microspheres which will be used in ACF (Anisotropic Conductive Film) with styrene as monomer, AIBN as initiator, and PVP as stabilizer. After the introduction of the basic knowledge and current development of ACF in electronic package, one of the key technologies of conductive micro-spheres for anisotropic conductive film (ACF) was developed. The effects of monomer feeding manner, concentration of PVP, and the composition of solvent on particle size and size distribution were carefully studied. And optimized recipes were achieved under which particles with mean particle size between 2-5μm and coefficient of variation lower than 5% could be synthesized. In this thesis, it was found that with increasing PVP concentration, the particle size descends while size distribution gets narrower, and adding monomer at a time also enhances the uniformity of particle diameter; and with the decrease of Solubility Parameter of solvent, particle size increases while its distribution gets broader, the dispersion polymerization carried through in ethanol/water, ethanol /formaldehyde, isopropanol/toluene supported this well; besides, additional usage of DVB in dispersion polymerization can obviously enhance Tg of polystyrene, but that would to some extent damage the uniformity and roundness of the particles. Additionally, the thesis