Preparation And Research Of TiO₂/Polyacrylate Functional Composite Material

Acrylate polymers have good moldability and are often used as coatings.Titanium dioxide（TiO₂）has many advantages such as self-cleaning,anti-fogging,and antibacterial.The organic-inorganic hybrid materials,which are formed by chemical bonding of the above two materials,not only maintains the original properties of acrylate and TiO₂,the insufficiency of acrylate matrix is also fully improved.When the hybrid materials are used as a coating,they can effectively increase the transmittance.In this project,butyl methacrylate（BMA）is used as an organic matrix,combined with nano-TiO₂to form hybrid material,and the related properties of the hybrid material coating are explored.Three particle sizes of nano-TiO₂ were prepared by sol-gel method.BMA,hydroxyethyl methacrylate（HEMA）and silane coupling agent KH-570were polimerized to prepare acrylate copolymer by radical polymerization.The organic-inorganic hybrid material was formed through condensation reactions between hydroxyl groups of copolymer and TiO₂.The structure of the hybrid material was characterized by FT-IR spectrum,which proved its successful synthesis.The hybrid material coating was coated on polyethylene terephthalate（PET）film by dip-pulling method.The light transmittance test found that the coatings with different particle sizes and different contents of nano-TiO₂ had increased the light transmittance of the film.Moreover,it was further increased after the secondary coating of silicone oil.Among them,when the particle size of nano-TiO₂ is 150 nm and the content is 8%,the light transmittance is the highest,which is 93.0%.Compared to the common blend materials,this kind of hybrid materials are more stable and excellent in performance.The contact angle results show that the contact angle of the coated film surface has increased,which gives the film a certain hydrophobic ability and enhances the self-cleaning ability of the film.In addition,thermogravimetric analysis（TGA）and differential scanning calorimetry（DSC）show that the thermal stability of the hybrid material was increased due to the chemical bond between the organic phase and the inorganic phase,which makes the material more stable.At the same time,the antibacterial properties of nano-TiO₂ endow the hybrid material coating with a certain antibacterial ability.Compared with pure PET film,the antibacterial rate reaches 60%.The titanium source was reacted withα-bromoisobutyric acid by solvothermal synthesis method to generate spherical titanium-oxo cluster（TPC）initiator.Then,TPC was reacted with BMA by atom transfer radical polymerization（ATRP）to form hybrid materials.The molecular weights of the hybrid materials were changed with the difference of the ratio of TPC and BMA.The X-ray photoelectron spectroscopy test showed the existence of Br element on the surface of TPC clusters,which proved the successful preparation of the initiator.In addition,the structures of TPC and the hybrid materials were verified by ¹H-NMR and FT-IR.After dissolving the hybrid material,it was coated on the surface of the PET film,and the UV and light transmittance tests were used to test.The results find that,the coatings with various molecular weights had the effect of increasing the transmittance.Among them,the best transmittance was up to 93.3%.In addition,the surface free energy decreased with the decreasing of molecular weight,which means the film became more hydrophobic.Scanning electron microscope showed that the synthesized TPC were spherical and the surface of the coated film was groove-like,which was also the reason for the increase of light transmittance and contact angle.What’s more,the static breath diagram method was used to coat the film,and the results showed that the contact angle of the film after coating by this method could reach 130.0°,and the hydrophobic ability was further increased.Although the light transmittance decreased,the haze increased,which obviously was beneficial to the exploration of light scattering.In addition,due to the high heat resistance of TPC,there is a higher rise in the thermal decomposition temperature of the hybrid material,making the material more durable.The step-like silsesquioxane（LPSQ）was prepared by the conventional hydrolysis and condensationof the coupling agent KH-570.The silicon-containing copolymer microspheres were synthesized by suspension polymerization of BMA,LPSQ and acrylic acid（AA）.Finally,micro-nano structured coating was prepared by the amidation reaction of microspheres and coupling agent KH-550 modified nano-TiO₂.The structure of LPSQ was characterized by ¹H-NMR and XRD,and the structure of the copolymer microsphere was characterized by FT-IR,which proved its successful preparation.The UV and light transmittance tests of the coating show that,compared with the light transmittance of pure PET film of 89.7%,the micro-nano structure coating has a significant effect of increasing the transmittance.Among them,when the nano-TiO₂ content reaches 5%,the light transmittance is the highest,which could reach 94.3%.The particle size of nano-TiO₂ will also affect the light transmittance.Among the four particle sizes studied,50 nm has the best effect.Due to the presence of a large number of hydrophilic groups on the surface of the micro-nano structure,the hydrophilicity is quiet well.The contact angle test shows that the contact angle of the coating surface was less than 20°,which also gave the coating a certain anti-fogging ability.In addition,TGA shows that LPSQ had excellent thermal stability,and that of the copolymer also increased significantly.What’s more,the antibacterial ability of the coating was enhanced due to the large amount of nano-TiO₂ contained in the outermost layer of the micro-nano structure.The test results show that the antibacterial rate of the coating reaches 93.3%.