Preparation And Characterization Of UV-curable Scratch Resistance Hybrid Coatings Based On Sol-Gel Method

Modern coating materials have been gradually becoming a type of multifunctionalengineering materials that hold an important position in the chemical industry. Nowthere are more and more researchers in our country and all over the world are makingtheir best effort to improve the synthesis process, optimize the technology, upgrade thequality of the product, and give the coating materials special features. Nanomaterialshave become the utmost concern among people recently due to their unique applicationsin many fields, such as optics, electronics, magnetism and so on. It provides people witha vision to combine the advantages of both nanomaterials and coating materials tocreate a new type of hybrid coating which is considered a innovative advanced material.Nowadays researchers have successfully finished the synthesis of a series of hybridcoating materials which include an inorganic phase of silica, alumina, titanium andzirconia nanoparticles. The inorganic nanoparticles give the hybrid coating materialspromising applications in many fields via providing the coating materials with newfeatures such as scratch resistance, high refractive index, anticorrosive property, gasbarrier, thermal resistance, refractory property and so on. In this paper, we haveprepared a type of surface-modified silica nanoparticles via the in situ sol-gel technique.Then we combined both the organic polymer and the inorganic nanoparticles together toform a high scratch resistance and transparent hybrid coating materials based on thedirect dispersion method and a new type of optimized experimental method.In chapter Two, we prepared a UV-curable epoxy-based transparent hybrid coatingmaterial for scratch resistance. The silica colloidal can be synthesized in isopropanolwhich used as co-solvent through a combination of hydrolysis and condensation reactions of the inorganic precursor （TEOS） and the coupling agent （KH560）. We choseKH560as the organic monomer of the hybrid coating materials because of its excellentoptical properties and its low viscosity. Compared with traditional polymers used as theorganic phase of hybrid coating materials, KH560monomer possesses its special featuredue to its structure of trialkoxysilane groups that has the capability of reacting with thesilica colloidal through the hydrolysis and condensation process under acidic conditions.During the combination of the silica colloidal and the organic monomer, we optimizedthe direct dispersion method. In the new method, we carried on the hydrolysis andcondensation reactions between the silica colloidal and the organic monomer in order toobtain a strongly interconnected network between the organic and inorganic phase.Moreover, the formation of the Si－O－Si during the reaction process can improve thecontent of SiO₂and the degree of cross linking of the organic phase. In this way, we canimprove the scratch resistance, toughness and hardness of the hybrid coating. Most ofthe hybrid coating materials were thermally cured. We employed the UV-curingtechnology during experiment due to its advantages, such as the rapidity of the process,its relatively low energy consumption, the ability to perform it at room temperature, itslower process cost. During our experiment we prepared a hybrid coating with a smoothsurface, excellent adhesion property with the substrates, high pencil hardness above6H,high transmittance in visible range above90%.In chapter Three, in order to widen the applications of the hybrid coating materials,we prepared a series of UV-curable acrylate-based hybrid coating materials for scratchresistance. In our experiment the silica colloidal was prepared in isopropanol whichused as co-solvent through a combination of hydrolysis and condensation reactions ofthe inorganic precursor （TEOS） and the coupling agent （KH570）. During thepreparation process, we used three types of acrylic resin which are commonly used inindustrial as the organic phase of the hybrid coating materials. We used the directdispersion method during the combination of the silica colloidal and the organicpolymer. For different kinds of organic polymers, the silica colloidal has its unique impact on the scratch resistance of the hybrid coatings. The hybrid coating can reach itsmaximum wear resistance property when we developed the most suitable content of thesilica colloidal. During this part of our experiment, we focused on the process of findingout the most suitable content of the silica colloidal in the hybrid systems in order toreach the maximum scratch resistance property of the hybrid coating.Overall, we have prepared the silica colloidal through a combination of hydrolysisand condensation reactions of the inorganic precursor and the coupling agent. Then wecombined the silica colloidal and the organic polymer together to obtain a series ofhybrid coating materials based on the direct dispersion method and a new type ofoptimized experimental method. These hybrid coating materials can be widely used inthe automotive industry, chemical industry, shipping industry, medical area, spacetechnology, furniture products, construction area and other fields.