Study On Influence Factors Of Environmental Friendly Nano-composite Coating Of Emulsion Containing Fluorine

In this paper, a kind of high performance environmental friendly nano-composite exterior wall coating containing fluorine is studied. The paper mainly includes the contents as follows.The first is the synthesis of emulsion containing fluorine. A kind of acrylate copolymer emulsion containing fluorine is prepared, with hexafluorobutyl mathacrylate, dodecafluoroheptyl methacrylate, butyl acrylate, methyl methylacrylate as ingredients. The experiments indicate that the best coplymerization reaction conditions are 90℃ , 160rpm and 2 hours. Among several kinds of emulsifiers, the experiment results prove that the composite emulsifier of MS-1, SDS, FC-10 is the best and it's best amount is 6%. The composite emulsifier of polassium perfluoro octane sulfonate and N-ethyl perfluoro octane sulfonyl amide is the best coptymerization too, it can improve the performance especially water adsorption. The orthogonality experiment results show that the type and quality of emulsifers have a remarkable influence on gel amount and the amount of monomer containing fluorine has deep influence on coplymerization, products' surface tension and water adsorption can be reduced by using emulsifers containing fluorine. Monomers containing fluorine can improve the contact angle of the film and reduce products' surface tension when the quality of fluorine is improved. MMA:BA has a little influence on gel amount. The Infrared spectroscopy test results indicate that the existence of reaction and the DSC test result indicates that emulsion products' Tg isl7.669℃和 23.432℃.The second is the preparation of nanoscale pigment. Nanoscale titanium dioxide powder is prepared in terms of sol-gel process with Ti(OC4H9) as raw material. The experiment results show that the productivity of nano-scale titanium dioxide is the highest when PH value of the hydrolysis system is about 2.5.TEM photoes show that the products' sizes are between 50-100nm.XRD tests indicate the crystal style of the products is rutile type. In order to apply nanoscale titanium dioxide to coating as pigment, it must be modified. The nanoscale particles are modified in terms of esterifying reaction, silane coupling agent and organic titanate coupling agent. The activation index and contact angle test results of the products prove the sequence of hydrophobic modification effect: organic titanate coupling agent modification > silane coupling agent modification > esterifying reaction modification.The third is the development of environmental friendly nano-composite coating containing fluorine. The coating is developed with modified nano-scale titanium dioxide, emulsion containing fluorine and additives as materials.The coating's formulation is determined in terms of experiments. The performance test results of thecoating indicate that it's performances are up to the national standard of synthetic resin emulsion coatings for exterior wall. The coating's performances are superior to acrylate emulsion coating for exterior wall. The hiding power of the coating is the best when the amount of nano-scale pigment is 25%.