Influence Of Polyacrylate/TiO₂ Composite Particles On The Light Stabilization Of Some Polymers

Most polymer materials, including plastics, rubber, fiber, coatings, will be destroyed by the sunlight outdoors, and the service life will be shortened. It's very important for polymer to carry on the research of light stabilization. In this paper, POM, PVC, PP, ABS, PVC/ABS alloy were modified by the polyacrylate/TiO₂ composite particles which were self-prepared in laboratory, and the effects of the particles on the microstructure and properties of above polymers were investigated.POM was modified by the polyacrylate/TiO₂ composite particles, the TiO₂ particles and the organic UV stabilizer. The effects of these substances on crystallization behavior, mechanical properties and the anti-ultraviolet ability of POM were investigated by differential scanning calorimetry (DSC), polarizing microscopy (PLM), wide angle X-ray diffraction (WAXD), scanning electron microscope (SEM) and mechanical properties testing. The results show that, compared with the TiO₂ particles and the organic UV stabilizer, the polyacrylate/TiO₂ composite particles could make the spherulites of POM become smaller, decrease the crystallinity of POM, and they were more compatible with the POM. After the UV irradiation for 500h, the elongation at break of unmodified POM declined from 49.58% to 26.52%, the retention was only 53.5%, while the the elongation at break of the POM modified with the composite particles declined from 66.66% to 55.60%, the retention reached 83.4%; the izod impact strength of unmodified POM declined from 5.81 kJ/m² to 2.00 kJ/m², the retention was only34.4%, while that of the POM modified with the composite particles declined from 5.92 kJ/m² to 4.58 kJ/m², the retention was 77.4%. The light stabilization of POM modified by the composite particles was better than that of TiO₂ particles and organic UV stabilizer.The feasibility of raising light stabilization of PVC by polyacrylates/TiO₂ composite particles was discussed through scanning electron microscope (SEM), differential scanning calorimetry (DSC), high-pressure capillary rheometer and mechanical properties testing. The results show that, polyacrylates/TiO₂ composite particles can improve the anti-ultraviolet ability of PVC effectively. For the sake of investigating the influence on the properties of PVC further, the samples injected were used. The morphology, rheological properties, the mechanical properties and the anti-ultraviolet ability of PVC were investigated by high-pressure capillary rheometer, scanning electron microscope, gel permeation chromatography(GPC), dynamic mechanical thermal analysis(DMA), colorimeter and mechanical properties testing. The anti-ultraviolet ability was mainly analyzed through the changes of microstructure and properties. The results show that, some polyacrylates/TiO₂ composite particles can improve the rheological properties of PVC. Through the comparison, the sample with 3% composite particles has the best comprehensive property, izod impact strength raise from 1.9 kJ/m^-2 to 7.14 kJ/m^-2, and the retention reach 92.4% after UV irradition. The better anti-ultraviolet ability of PVC modified with composite particles can be proved from microstructure, including the less cracks, less broken molecular chains, smaller change of molecular weight and molecular weight distribution, the molecular weight of modified samples (3%) descend from 103000 to 86400, the molecular weight distribute change from 1.97 to 2.21, but the molecular weight of unmodified samples descend from 115000 to 63100, the molecular weight distribute changes from 1.81 to 2.66. It can be also concluded that modified PVC can restrain the trend to turn yellow from the change of yellow index(YI). The effects of polyacrylates/Ti02 composite particles on the the mechanical properties and the anti-ultraviolet ability of PP, ABS, PVC/ABS were investigated. Through the testing, the light stabilization of PP and ABS which were modified with composite particles are better than that of unmodified salpmes. The influence of composite particles on the anti-ultraviolet ability of PVC/ABS is not obvious. It need more research when the polyacrylates/TiO₂ composite particles are applying for PP, ABS and PVC/ABS alloy.