Research On The Preparation And Properties Of Ultraviolet Curing Organic-Inorganic Hybrid Coating

Permanent interest in UV-curable systems is notably demonstrated by the numerous studies published in this field over the passed years. The main reasons for this interest are the considerable advantages offered by the UV-curing process of polymerization over more conventional processes such as thermal curing, including very high speeds of curing that lead to high productivity, lower energy consumption, reduction of volatile organic compounds emissions, and so forth. Unlike in thermal curing, the curing time is in the order of magnitude of minutes rather than hours, which means a significant reduction in cycle time. As no heating is required, the energy consumption is lower than that in conventional processes and the tool design is less complex. The radiation can be generated by a variety of sources suitable for various specific applications and different curing strategies. The properties of the UV-cured polymer matrix are determined by the cross-linking density, which depends on the type and concentration of the photoinitiator and of the (optional) diluents, the intensity and the duration of the irradiation, and the temperature, at which the curing process takes place. The theory and development of ultraviolet curing materials and organic inorganic hybrid materials have been reviewed in chapter 1. In chapter 2, tailoring materials with well defined and predetermined characteristics requires the knowledge of structure–property relationships between the crosslinkable prepolymer and the final network. PUA precursors are synthesized by the reaction of a polyol with an excess of a diisocyanate. An hydroxyethyl methacrylate is then added to the resulting product to react with the remaining NCO groups, thus bringing the reactive acrylic functions to the molecules. The control of the properties of the PUA precursor in relation to the synthesis procedure and the reagents used (the nature and molar mass of the polyol, the nature and concentration of the diisocyanate, etc.). A photoinitiator is incorporated to induce the free-radical polymerization of the acrylated precursor when exposed to UV radiation. Industrial formulations often include additional components, among them monofunctional and multifunctional acrylate monomers (reactive diluents), to decrease the viscosity of the formulation and modify the crosslinking density of the final network. Polyurethane acrylate (PUA) constitute a class of materials widely used in ultraviolet (UV)-curable formulations to produce flexible and abrasion-resistant coatings. A complete understanding of the morphology of the network and the mechanisms occurring during its formation.In chapter 3, as a silicon coupling agent, KH570 modifies the suface of nano titanium dioxide particles which after that are compound into ultraviolet curing resin system to prepare organic inorganic nano-level hybrid film materials. Another way to synthesizing hybrid system is adding nano titanium dioxide prepared by sol-gel method into prepolymer and reactive monomer solution, which form the hybrid network structure by using ultraviolet or light curing technique. The polyurethane-epoxy acrylate/nano titanium dioxide hybrid films have uniform phase without phase separation between organic and inorganic components. We study on hybrid mechanism and interior network structure and gain the performance.