无机纳米粒子改性丙烯酸酯涂料的制备及其光老化性能的研究

【作者】 陈建军；

【导师】 王智宇；

【作者基本信息】 浙江大学 ， 材料学， 2004， 硕士

【摘要】 本论文拟研制新型高耐候无机纳米粒子改性水性丙烯酸酯外墙涂料。 在全面综述新型聚合物紫外光稳定剂的研究发展和应用状况的基础上，从材料的紫外光屏蔽性能出发，确定选用纳米TiO₂、SiO₂、ZnO作为涂料的光稳定材料。论文概括了无机纳米材料的各种制备技术，尤其着重介绍了湿化学方法制备纳米材料方面的最新进展，总结评述了当前无机纳米材料改性聚合物各种制备技术发展的现状及其问题。 在此基础上，为解决纳米粉体的团聚问题，使纳米粒子在涂料中有效分散与附聚，以实现纳米粒子改性的有效性，原创性地提出了原位生成纳米粒子改性涂料制备工艺的新思路：利用湿化学方法制备纳米材料的技术，在常规涂料制备的过程中加入所需引入纳米粒子的先驱物，直接在颜填料微粒的表面原位合成相应的纳米粒子。同时提出在位分散法纳米粒子改性涂料的制备技术：直接在涂料中引入采用湿化学方法制备的纳米粒子溶胶，而不是采用外加经过过滤和烧结等工艺制备的纳米粉体。原位生成纳米粒子改性法将纳米粒子的合成与分散一步完成；在位分散法纳米粒子改性工艺直接将纳米粒子溶胶与涂料进行分散，一定程度上避免了纳米粒子的团聚，保证了纳米粒子改性的有效性。 论文采用络合物水解法在常温下成功地制备了均匀分散的纳米TiO₂溶胶，并采用原位生成法制备了纳米TiO₂改性水性丙烯酸酯涂料。通过考查纳米TiO₂溶胶的紫外光吸收和散射性能发现纳米TiO₂溶胶对紫外光有很好的吸收屏蔽效果，在320nm以下紫外光波段的透过率几乎为零，且随着纳米二氧化钛粒径的变小，其紫外光吸收蓝移；研究了络合物水解法制备的工艺因素对纳米TiO₂紫外吸收和散射性能影响的相关规律；采用原位生成法制备的纳米TiO₂改性水性丙烯酸酯涂料的耐老化性能优异：人工老化1800小时后仍无粉化、起泡、剥落、裂纹等老化迹象，远远超过国标优等品要求的600小时粉化1级的标准，而相应的未改性涂料在人工老化1600小时时，粉化已达到1级。 用溶胶—凝胶法制备了稳定的纳米SiO₂溶胶，并采用在位分散法制备了纳浙江大学硕士学位论文米510:改性水性丙烯酸酷涂料。实验证明:纳米510:溶胶具有很强的紫外散射屏蔽性能，对400nm以下的紫外光能屏蔽90%以上;在位分散法纳米510:改性涂料的耐人工老化粉化时间比直接分散法纳米510:改性涂料提高了近1倍，耐变色时间（达到色差2级的时间）是国标优等品要求的1.83倍，较相应的未改性涂料提高了约25%。 通过原位生成法制备的纳米TIO:改性涂料和在位分散法制备的纳米510:改性涂料具有超强的耐候性能，以人工老化100h大约相当于室外曝晒一年计算，纳米改性的涂料在室外的使用寿命可超过18年。更多还原

【Abstract】 The paper was intended to study a kind of waterborne acrylic resin exterior wall coatings with strong weatherability by the way of using inorganic nanoparticle as age-inhibiting addition.Based on the comprehensive summary of the research and application of the modern ultraviolet radiation stabilizing agent, we began with the property of the UV shielding and chose the nano-TiO2, SiO2, ZnO as the UV shielding agent. In this thesis, we made a summary of the preparation technology of the nano-materials, especially of the latest development of preparing nano-materials by the way of the wet chemical method. The preparation methods of the nanocomposite materials were summarized too.In order to solve the problem of conglomeration of the nanoparticle and make the nanoparticle disperse evenly in the coatings. In this way, we could succeed in improving the effect of modification .We originally put forward the in-situ sythesising nanoparticle method to modify coatings. Through this method, we made use of the technology of the wet chemical method and added the precursor of nanoparticle during the preparation of coatings. Meanwhile, the nanoparticle was formed on the face of the pigment. We also put forward the technique of in-situ dispersion to modify coatings .The key of the technique was to add the nanoparticle sol prepared by the wet chemical method into coatings instead of dropping the nanoparticle powder prepared by the technics of filtration and calcinations in the coatings. The preparation and the dispersion of the nanoparticle were finished in the same step by the first method. The second method could also solve the problem of dispersion in some way. Thus the efficiency of the modification could be assured.We succeeded in preparing the nano-TiO2 sol through the hydrolyzation of complex in the room temperature and preparing the nanoTiO2-modified coatings by the way of in-situ sythesising method. First, the UV absorbing and scattering characteristics of the nano-TO2 sol were studied. The sol of the nano-TiO2 had excellent shielding effect on UV radiation. UV transmittance below 320nm was nearly zero, and the absorbingof UV radiation was moved to short wavelength when the granularity of the nano-TiO2 was becoming finer. The influence of the technics of the hydrolyzation of complex on the UV shielding was studied. Then, we examined the weatherability of nano-TiO2-modified coatings prepared by the way of in-situ sythesising method. There were no aging phenomena such as chalking , bubbly , crackling , peeling-off after 1800h of the artificial aging process, which went far beyond the national standard for the super coating(the first level chalking after 600h of the artificial aging process). The common coatings reached first-degree chalking after 1600h of the artificial aging process.The stable nano-SiO2 sol was prepared by Sol-Gel method and the nano-SiO2-modified coatings were prepared by the way of in-situ dispersion method. The UV scattering characteristic of nanometer SiO2 sol was studied. The nano-SiO2 sol had excellent reflecting and absorbing effect on UV radiation. 90%UV below 400nm could be shielded by the nano-SiO2 sol. The time of the artificial aging of nano-SiO2-modified coatings prepared by the way of in-situ dispersion method was about twice as long as that of the nano-SiO2-modified coatings prepared by dispersing the nano-SiO2 powder in the coating directly. On the other hand, the fadeproof time (reaching the second level of color aberration) of the nano-SiO2-modified coatings was 1.83 times as long as that of the national standard for the super coatings. There was an increase in the fadeproof time of 25 percent over the common coatings.Both the nano-TiO2-modified coatings prepared by the way of in-situ sythesising method and the nano-SiO2-modified coatings prepared by the way of in-situ dispersion were strong weatherability coatings, which could resist 18 years’ weathering if we calculated the result with the standard which argued that 100h of the artificial aging process was equal更多还原