Preparation Of Monodisperse Polystyrene Microspheres For Anisotropic Conductive Film

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 discussed the mechanism of radical polymerization of linear/crosslink polystyrene in detail.