【作者】 汤先文；

【导师】 单松高； 张超灿；

【作者基本信息】 武汉理工大学 ， 材料学， 2003， 硕士

【摘要】 本论文分别采用化学法和无皂乳液聚合法对纳米二氧化硅进行表面改性。改性后的纳米二氧化硅在不同含量的情况下与聚丙烯酸酯乳液复合配成纳米外墙涂料，研究其最终涂膜性能，并重点分析纳米外墙涂料耐洗刷和耐沾污性能改善的情况。 文中采用单质硅法制得固含量为25～30％、粒径10nm左右的稳态下(PH=9)的纳米二氧化硅水溶液。分别采用化学法和无皂乳液聚合法对其表面进行改性。化学法所用改性剂为硅烷WD-30接枝不同分子量聚乙二醇制得，改性后使得纳米二氧化硅表面具有双亲性能，有效改善其界面状况。无皂乳液聚合法是在无乳化剂存在的环境中，利用纳米二氧化硅表面的吸附力，单体(MMA)在其表面进行聚合，包裹纳米二氧化硅表面，改善界面状况。通过电镜和电位测试，都表明两种改性方法都很好地改善了纳米二氧化硅的分散性：二氧化硅团聚体粒径由未改性前的120～200nm缩小为80nm左右。 纳米二氧化硅改性方法和纳米二氧化硅的含量对实验结果的影响：总的说来，一般化学改性方法由于强化学键作用，效果要好于无皂乳液法。单从化学法本身看，接枝PEG的分子量越大，结果越好，耐沾污性能表现尤为明显；无皂乳液聚合也许由于本身方法的因素使得MMA包裹量对结果影响不显著。纳米含量在颜填料比例范围内，一般对实验结果有利，例如硬度数据随纳米含量提高线性升高。 配置了以纳米二氧化硅为添加物的纳米涂料，检测各项性能提高或改善的情况。实验结果表明，涂膜的力学性能得到提高，如拉伸强度、断裂延伸率和表面硬度；涂料的耐洗刷性能和耐沾污性能有改善，但防水性能和抗紫外性能无明显改善，接触角和吸水率数据无规律可循。 温度对涂膜耐沾污性能的影响：一般是外界温度越高，涂料耐沾污性能就越低，而且受纳米含量影响更大。更多还原

【Abstract】 In this paper ,two kinds of surface modification method(chemical measure and soap-free polymerization ) are used. After the surface of nano-silica was modified, nano-coating is prepared by mixing nano-silica into polyacrylate emulsion. The properties of membrane formed have been proved to be improved. More emphasis will be put on analyzing stain resistance and scrubbing resistance.Nano-silica in aqueous solution(solid content w =25%-30%, particle size s=8-15nm, PH=9) has been prepared by silicon. Then two modification measures are used to modify nano-silica particle. According to chemical method , modifier is got by silane coupling agent (WD-30) grafted with PEG of different molecular, which make the surface of nano-silica amphiphilic and improve the interface of nano-silica. Soap-free polymerization method means monomers(MMA) polymerize around the surface of nano-silica without soup, absorbed by the force of surface. By the means of TEM and potential test , the improvement of dispersal of nano-silica has been proved: particle size of aggregates decreased from 120-200nm to 80nm.Effects of modification measure and the content of nano-silica to experiment generally chemical measure, with higher chemical band force , will lead to better results than soap-free polymerization measure. To chemical measure , the higher molecular of PEG is, the better result will be got; to soap-free polymerization ,on the contrary , the content of PMMA enwrapping nano-silica effect few on results, which is obviously shown in data of stain resistance. With the horizon in rate of pigment and filler, high content of nano-silica will be benefit to result of experiment, for example , rigidity will increase with the content of nano-silica raising.Making up nanopaint mixed with nano-silica ,the improvement of its properties has been tested. The mechanic property of membrane formed increased , such as tensile strength, elongation at break, surface rigidity;The scrubbing resistance and stain resistance of the paints has been improved . But it’s the limitation that ideal results of properties of waterproofing and UV-screen haven’t beengotten. Few disciplinarian can be found from the data of contact angle function and water absorbency.Effects of temperature to stain resistance : with higher circumstance temperature ,stain resistance will be lower, and more easily effected by content of nano-silica.更多还原