Preparation Of Nano-SiO₂Hybrid Materials With Mercapto Group And Investigation Of Its Effect On The Properties Of UV Curing Coatings

UV curing technology is a kind of science and technology with "5E" characteristics, therefore, the advantages of UV curable material is self-evident. With the development of modern socity, it is increasingly strengthened the protection of the environment and requirements for UV curable materials is also higher and higher. In recent years, the research and development of domestic UV curable materials have achieved grest progress, but there are still some deficiencies which need to be improved. To overcome oxygen inhibition effect in the UV curing process and improve the cured film hardness, wear resistance and other mechanical properties, the compounds or nano-SiO2with-SH groups were added to the traditional light-curing coating to get organic/inorganic hybrid materials. The final light-curing products have fast curing rate and the curing process was complete. What’s more, the mechanical properties of the cured product had been improved a lot. This paper mainly uses the following three methods:(1) Because the surface of the nano-SiO2has many hydroxyl with various state, the γ-mercapto propyl trimethoxy silane (KH-590) containing the structure of-SH groups was used to modify the nano-SiO2. The modified nano-SiO2particles were added to UV curable coatings. We respectively determined the viscosity of different hybrid system and the hardness, wear resistance, thermal stability of its cured film. The results showed that the mercapto group was grafted on the surface of nano-SiO2. The modified nano-SiO2dispersed evenly in the UV coating. Because the role of the mercapto group, the effect of oxygen inhibition can be overcomed in the light-curing process and the carbon-carbon conversion rate was higher than before. Compare the cured coatings with modified nano-SiO2to cured coatings with nano-SiO2, the physical and mechanical performance had been improved obviously.(2) The modified nano-SiO2with mercapto group was prepared by Sol-Gel. First, the tetraethoxy silane(TEOS) is hydrolyzed. Then add the-mercapto propyl trimethoxy silane to the hydrolyzate. Finally, the hybrid material was added to the light-curing coatings. The results showed that the nanoscale organic/inorganic hybrid materials with mercapto group was prepared. When the dosage of KH-590is35%, the grafting rate is23.8%and the nano-SiO2composite dispersed evenly. The hardness, wear resistance of the coating had been improved significantly. Meanwhile, compare the coating with nano-SiO2composite to the coating with nano-SiO2, the curing rate had been improved and C=C conversion rate is from73%to75%.(3) Combine the KH-590With TMPTA and choose the triethylamine as catalyst, the organic compounds containing a thioether bond was gotten through Micheal addition reaction,then reacting with nano-SiO2,finally obtained organic/inorganic composite materials. Add it to light-curing coatings and determine the mechanical properties and curing rate. The results showed that the grafting rate can reach26.5%. The viscosity of coating with nano-SiO2composite is lower and the physical and mechanical properties were significantly improved.