Investigation On Ageing Resistance Of Modified Polymer Materials With Nanosized Rutile Titanium Dioxide

Nanosized rutile TiO2(nano-rutile-TiO₂) was mass-produced early among most inorganic nanosized materials. Due to its with excellent ultraviolet shielding function, stabile character of chemistry nanosized rutile TiO₂ particles have been used extensively in many fields such as sunscreen cosmetics, automotive topcoats, anti-ultraviolet and so on. It will supersede the organic ultraviolet absorbents step by step. In this dissertation, polymer/nano-rutile-TiO₂ composites with great ageing resistance were obtained. The mechanism of ageing resistance was also investigated.Deep investigation and analysis on high performance, application and theory of polymer/nano-rutile-TiO₂ composites were carried out. A lot of valuable information was obtained that can be used for development of polymer/nano-rutile-TiO₂ composites, six invention patents were applied. Therefore, this work obtained the following new creative results and progresses and reaches the expect goals.1. The morphology, size, composition and optical characteristics of bulk-rutile-TiO₂, nano-rutile-TiO₂, nano-anatase-TiO₂ and nano-ZnO powders were studied by TEM, FTIR, XRD, XPS and UV-Vis spectrum. The results showed that the nano-rutile-TiO₂ has the strongest UV absorption at the same thickness, and the UV-shield mechanism of these materials was also discussed.2. When the surface was processed by ultra-high speed mixer-grind complex technic (CDUH technic) , nano-rutile-TiO₂ could be well dispersed in polymer matrix (PP, ABS,HIPS, PC and polyester-TGIC powder coatings) on nanoscale. The paper also studies the dispersion state of nano-rutile-TiO₂ in polymer matrix with the aid of SEM and TEM.3. Polymer/nano-rutile-TiO2 composites were prepared by melt-blending process. The accelerated aging test of pure polymer materials ( PP, ABS, HIPS, PC ) and polymer/nano-rutile-Ti02 composites was conducted with laboratory xenon arc lamp (GB/T16422.2-1999) . The IZOD impact strength changes of these materials during artificial weathering were measured. It was shown that, with the addition of nano-rutile-TiO2, the ageing resistance of polymer/nano-rutile-TiO2 composites have been improved; as a result the survice life of polymer/nano-rutile-TiO2 composites have been prolonged and the tougheness of polymer materials have been increased to a great extent too. A new configurable model of integration technic weatherproof polymer materials modified with nano-rutile-TiO2, UV-absorbent, HALS and elastomer was established for the first time. The ageing resistance of polypropylene/nano-TiO2/POE composites is better than polypropylene/bulk-TiO2/POE composites. IZOD unnotched impact strength of polypropylene/ (1.0wt%) nano-TiC^/POE composites which was improved four times than pure PP is 80.45KJ?m 2 after 28 days exposure to xenon arc lamp. Polypropylene/( 1.0wt%)bulk-TiO2/POE composites's impact strength is only 47.88 K>m"2 after 28 days exposure to xenon arc lamp.4. Nano-rutile-TiO2 were used to modify polyester powder coatings for the first time in this dissertation. The nano-rutile-TiO2(2wt% and 5wt%) modified polyester-TGIC powder coatings were prepared. The introduction of nano-rutile-TiO2 to the powder coatings improved the cured film ultraviolet ray resistance distinctly. The aberration of powder coatings modified by nano-rutile-TiO2(2wt%) is less than 1.52, and the gloss percent retension is more than 50% after 192 hours exposure to mercury-vapor lamp which was improved four times compared with the unmodified one. The research results were practicable and had great engineering significance in utilizing nano-rutile-TiC>2 into weatherproof polymer materials and new engineering application field.5. In this dissertation the ageing mechanism of the pure polymer materials and modified polymer materials were studied with the aid of FTIR, DSC, GPC, HPLC, SEM and UV-Vis. According to FTIR analysis, it was found that there is a linear relation between carbonyl index and impact properties of pure PP after accelerated aging, and their correlation coefficients are more than 0.9. By fracture analysis it was found that there is a linear relation between smooth region proportion and impact properties of pure ABS after accelerated aging, and theircorrelation coefficient is 0.9543. The carbonyl index of PP/nano-rutile-TiO2 composites has a little change after accelerated aging. The molecular mass of pure polymer materials had decreased to a great extent after 28 days artificial weathering. The DSC data showed that nano-rutile-TiO2/POE accelerated the crystallization rate and increased the crystallization temperature of PP. The glass transition temperature of pure ABS increased by 9.69°C after 28 days artificial weathering. The UV transparency of the films can be reduced significantly even when the content of nano-rutile-TiO2 was very low : the UV transparency of the PP/POE film filled with 0.5wt % nano-rutiIe-TiO2 and the PP/POE/HALS film modified with 0.5wt % nano-rutile-Ti02 decreased by 40.17% and 56.09 %, compared to the PP film. The UV transparency of PP and PP/POE films was increased by 12%and 22% after 1 day exposure to mercury-vapor lamp. There are little change for the molecular mass, the glass transition temperature and the UV transparency of polymer/nano-rutile-TiO2 composites after 28 days artificial weathering.6. The processing of weatherproof polymer/nano-rutile-Ti02 composites was enlarged to ton grade from many times small-scale test, and the obtained composite materials had great ageing resistance and longer service life at outdoor. The method and technics have good prospects on the spread and the application. The research results might give a new design method and new kinds of materials for solving the mechanical properties and surface quality failure of weathering and manufacturing weatherproof polymer materials.lt was also revealed that results can achieve the preparation of polymer/nano-rutile-Ti02 with high toughness and great ageing resistance including the choice of matrix and the design of the composition, which lay a foundation of industrialization of polymer/nano-rutile-TiO2 with high performance and low cost.