Studies On Structure And UV-resistant Performance Of Polymer/TiO₂ Composite Particles Containing Organic UV-Absorber Group

Polymer can be destroyed by ultraviolet. In order to protect polymer from UV destroy, firstly, we introduce the reactive organic UV-absorber 2-hydroxy-4-(3-methacryloxy-2-hydroxylpropoxy)benzophenone (BPMA) into the polymer chains by covalent bond via emulsion polymerization. The BPMA content can absorb ultraviolet and protect polymer from UV destroy, the service life of the polymer will be prolonged. Then we introduce the inorganic UV-stabilizer TiO₂ into the polymer chains by covalent bond.TiO₂ can shield the ultraviolet, and the UV-resistant performance of polymer can be enhanced. Further, after we combine the organic UV-absorbers BPMA and the TiO₂ with polymer by covalent bond, the UV-resistant performance of polymer can be enhanced highly by the effect of organic UV-absorber BPMA and inorganic UV-stabilizer TiO₂ together.In this paper, there are five chapters. The first chapter is the introduction, and the fifth chapter is the conclusions. In the second chapter,P(MMA-co-M12-co-BPMA) and P(St-co-M12-co-BPMA) emulsions were synthesized by a reactive surfactant sodium sulfopropyl-laurylmaleate (M12) and a polymerizable UV-absorber BPMA via emulsion polymerization. The monomer conversion measurement was used to study the influence factors of rate, Fourier transform infrared spectroscopy (FTIR) was used to determine the structure of copolymer and Ultraviolet-visible absorption spectroscopy (UV-Vis) was used to study UV-resistance of copolymer and emulsion. The results indicate that the P(MMA-co-M12-co-BPMA) copolymer can be obtained by the copolymerization of methyl methacrylate(MMA) with M12 and BPMA, P(St-co-M12-co-BPMA) can be obtained by the copolymerization of styrene(St) with M12 and BPMA. The copotymerization rate increases with the increase of M12 content, and the copolymerization rate decreases with the increase of BPMA content. The UV-resistance of the copolymer emulsion and copolymer can be enhanced with the increase of BPMAIn the third chapter, in order to obtain the P(MMA-co-M12-co-BPMA)/TiO₂ composite particles in which PMMA combine the organic UV-absorbers and the titanium dioxide with covalent bond, a reactive W-absorber BPMA, a reactive surfactant M12 and methyl methacrylate (MMA) were used to copolymerize with modified titanium dioxide via emulsion polymerization. To study the structure of composite particles, X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), ultraviolet-visible absorption spectroscopy (UV-vis),thermogravimetric analysis (TGA), and differential scanning calorimeter (DSC) were used. The measurement results indicate that the percentage of grafting and the grafting efficiency can reach 336.9% and 36.4%, respectively, the onset temperatures of thermal decomposition of composite particles is 359.2℃, and the glass transition temperature of composite particles is higher than that of P(MMA-co-M12-co-BPMA).The composite particles were irradiated under UV light , the weight loss and the glass transition temperature were investigated to determine the degradation of composite particles. The results show that BPMA and TiO₂ are effective UV-stabilizers in protecting PMMA from UV destroy, and the UV-resistant performance of PMMA can be highly enhanced. In the fourth chapter, the P(St-co-M12-co-BPMA)/TiO₂ composite particles were prepared via emulsion polymerization. The measurement results indicate that BPMA and M12 are copolymerized with styrene on the surface of TiO₂, the percentage of grafting and the grafting efficiency can reach 513.9% and 59.9%,respectively, the shape of the composite particles was core-shell ,and the glass transition temperature of composite particles is higher than that of P(St-co-M12-co-BPMA) . The UV-Vis measurement result also indicates that the P(St-co-M12-co-BPMA) grafted from the surface of TiO₂ keeps the excellent characteristic of BPMA that possesses high absorbance of ultraviolet light. The weight loss and DSC measurement results indicate that the polymer grafted from the surface of TiO₂ possess high absorbance of ultraviolet light, were hardly degraded after 500h UV irradiation. These results show that the UV-resistant performance of polystyrene can be enhanced by introduction of the organic UV-absorber and the titanium dioxide into the polystyrene chains by covalent bond .These research results are very important for preparing polystyrene that can resistant to UV light.