Study On The Organsilicon-modified Acrylate-styrene Microemulsion Coatings By Photopolymerization

The organosilicon modified polyacrylate microemusions synthesized by copolmerization of monomers with different polarities such as acrylate, styrene and organosilicon have good performances such as water dispersion system and zeroVOC emission which meets the environmental requirements. Therefore how to synthesis of the organosilicon modified polyacrylate microemusions have vital significances not only theoretically but also practically. Effects of surfactant, cosurfactant, monomer, St/BA mass ratio, photoinitiator on the monomer conversion during the microemulsion photopolymerization are systematically investigated. The components of the photopolymerization systems have been optimized. The synthesized organosilicon modified polyacrylate microemusions have good transparency and stability as well as good acid, base, water and heat-resistances together with nanoscale latex particles and narrow size distribution in the polymer matrix. The main results obtained in the article are as follows:1. The optimum components of the rapid formed and stable organosilicon modified polyacrylate microemusions is the 20% mass fraction of monomer based on water mass, 7:3 mass ratio of St to BA, 1.5% photoinitiator, 6%～8 % mass fraction of surfactant based on water mass and 5% mass fraction of cosurfactant based on water mass.2. The organosilicone-modified styrene-acrylate microemulsions had better acid resistance than base resistance. The microemulsions keep stable after more than 15mL HCl is added into the microemulsions.3. With increase in the surfactant amount in the photopolymerization systems, the photopolymerization rate and transparency of the rganosilicone-modified styrene-acrylate microemulsions increased, while the film formation, water, acid and base resistance of the organosilicon modified polyacrylate microemusions decreased.4. With increase in the amount of silane coupling agent KH570 in the photopolymerization systems, the thermal stability, water, acid and base resistance of the organosilicon modified polyacrylate microemusions increased.5. With post-thermal treatment, the thermal stability, water, acid and base resistance of the organosilicon modified polyacrylate microemusions increased.6. FTIR spectra of organosilicon modified polyacrylate microemusions shows the characteristics of absorption peaks related to units of acrylate, stryene and silane coupling agent, which indicates the structure of the organosilicon modified styrene and acryalte copolymer.7. Through optimization of photopolymerization techniques, the organosilicon modified polyacrylate microemusions has transimittance of 55% and 87% at 550nm and 760nm, respectively. TEM indicated that the microemulsion latex particles had average particle diameter of 42.6nm in the range of 30-60nm. Therefore the organosilicon modified polyacrylate microemusions, with small average particle size (2 9.1-37.9nm) a nd narrow particle size distribution (SDI=1.12～1.18), high solid content and high transparency have successfully been obtained by way of the microemulsion photopolymerization.