Preparation And Properties Of Transparent Coating For Polyacrylates Copolymer Modified With Organosilicon

The glass has the specific surface properties such as high surface free energy and hydrophile. In general the surface energy decreases obviously when the water drop on it and the in case glass surface is absolutely clean, the water on it will extend freely. In this case the water contact angle approaches zero and flow down when the surface leans. While in fact there must be some dust and other filth on the glass so as to the solid surface is not smooth. The water drop will adhere to such surface. This phenomenon could be seen anywhere like the glass window or the plastic raincoat. Nowadays the brush or cool wind system has been used in automobile to blot out or lustrate the water drop. However these equipments used has its own shortcoming. The former sometimes disturbs the line of sight of the driver, while the latter waste more energy. China is a big country with many automobiles and large population. Therefore the research on the modification of hydrophilic glass surface and its application would bring enormous social and economic benefit.In this thesis, our main goal is to prepare a transparent and hydrophobic coating on glass. There are two routes for this purpose : (1) preparation of organosilicon-polyacrylic resin through chemical mixture in order to decrease the surface free energy and improve the hydrophobic capability due to the trend of organosilicon of transfer to the surface. (2) synthesis of different kind of organosilicon-polyacrylic resin was synthesized through solution polymerization, which made the organosilicon section in the main chain. The chemical structure and the molecular weight of the products were characterized by FT-IR, !H-NMR and GPC. Its hydrophobic property, heat-resistant property, transmissivity, solid content and water-resistant property were also discussed.Firstly, polyacrylic resin with hydroxyl group ( OH ) in side chain was synthesized using four acrylic monomers MMA, BA, EA, HEMA by solution polymerization. The product structure was confirmed by FT-IR, GPC, solid content test and curing percentage test.Different kinds of organosilicon-polyacrylic resin was prepared using different kinds of silicone couples, like KH550, MTMS, KH560 blended with polyacrylic resin and cured under room temperature. Through an examination of the hydrophobic properties, we found that the hydrophobic capability is dependent on the functional group of silicone couples. Generally, the more content theorganosilicon, the longer the group. And the more hydrophobic the group, the better the effect. Meanwhile, the properties of heat-resistance, water-resistance and transmissivity were also studied.On the other hand, another kind organosilicon-polyacrylic resin was prepared using monomers like MMA, BA, BMA, KH570 synthesized by solution polymerization. The results of various tests revealed that to some extent, the properties of the product could be improved. Compared with the resin made by chemical blend, we found that the hydrophobic capability has been hardly improved. ATR-IR test indicated that the physical blend method is more favorable for the organosilicon transfer to the surface of the coating.In summary, by incorporating organosilicon and polyacrylic resin, the transparent and hydrophobic coating with good properties could be achieved.