【作者】 毛淑才；

【导师】 陈焕钦；

【作者基本信息】 华南理工大学 ， 化学工程， 2005， 博士

【摘要】 建筑业的飞速发展和环境法规的出台令建筑水性涂料发展前景看好，虽然市面上建筑外墙涂料花样繁多，但中低档产品供大于求而中高档产品不足，所以开发高档、高性价比的乳液和涂料是当务之急。目前，对纯丙、硅丙乳液和相应涂料的研究已取得一定成果，但对含氟乳液和相应涂料的研究仍处于起步阶段。含氟涂料具有高耐候、耐擦洗、耐化学药品、耐沾污等性能，满足了许多领域的特殊要求而得到应用，把氟树脂与丙烯酸酯类树脂相结合，可以在性能上取长补短，制备兼具两者优异性能的新材料，在理论和应用上都具有重要意义。 国外已报导了几种制备含氟乳液的方法，但在国内由于存在这样或那样的问题而难以适用。本实验另辟蹊径，避开氟烯烃单体聚合的步骤，把工作定位于对工业品聚四氟乙烯(PTFE)分散液进行微观(乳胶粒内的)复合改性，生成的乳液介于粘合剂(binder)和填料(filler)之间，相当于把PTFE看作是填料，将之作粘合剂性能处理，即用丙烯酸酯对其进行改性，获得在功用上更偏向于粘合剂的乳液。本实验工艺相对简捷，成本不高，得到的乳液性能比纯丙乳液有较大的提升，特别是在耐候性和耐沾污性方面，且能够常温成膜，是一种新颖有效地制备含氟乳液的新方法。 研究工作主要包括以下内容： 以含氟乳化剂和非离子乳化剂OP-10复配制备纯丙乳液，乳液比一般方法制备的纯丙乳液具有更好的稳定性，外观亮泽饱满，各种性能优异。详细分析了采用复配乳化剂制备纯丙乳液和聚四氟乙烯/聚丙烯酸酯复合改性乳液的工艺条件和原材料的选用依据，进行乳液聚合实验，制得了两种不同情况的微观复合改性乳液。 对得到的乳液产品进行表征、测试，设计了五种独立而又相辅相成的方法对实验设计思想进行求证，包括红外光谱法、透射电镜法、粒度分布法、小粒径外来种子聚合法、流变性变化法，各种结果表明设计思想是可行的。考察了乳胶粒的结构，并从宏观和微观两个方面探索了复合改性乳液的制备机理。 测试了产品乳液的各项性能，考察了初始种子用量、单体用量及比率、乳化剂用量、引发剂用量、反应温度等实验条件对产品乳液性能的影响；考察了影响聚合反应稳定性的因素。最终确定体系乳化剂用量为1.8％～1.9％；初始种子百分数为14％～18％；复合改性乳液的固含量确定在40％～50％之间；功能单体控制在单体总量的3％以下；制备二级种子时，单体对初始种子采用常规溶胀法；搅拌速度控制在120～250rpm，且搅拌速度应均一稳定；引发剂选用过硫酸氨，对更多还原

【Abstract】 Rapid development of architecture industry and issuing of environment laws make architecture waterborne coatings a good development foreground. Although there are various kinds of exterior wall waterborne coatings in the market, low-class products exceed purchasing needs and high-quality products are short of supply, so developing high-quality and high-performances, low-price emulsions and corresponding coatings are urgent. At present, researches of acrylate emulsions, alkoxy silane modified acrylate emulsions and corresponding coatings have made more progress, but researches of fluoro-containing emulsions and corresponding coatings just are in the stage of initial step. Fluoro-containing coatings are of high weather resistance, scrub resistance, chemical solvent resistance and stain resistance, etc., which meet some special requirements of many fields. Combining fluoro-resin and acrylate resin will combine their merits and improve their performances. To prepare novel materials with excellent performances of both resins is of great significance.Several methods to prepare fluoro-containing emulsions have been reported, but because of some reasons they are difficult to utilize in domestic market. Our research group used different way, avoiding fluoro-olefin polymerization, to modify commercial product polytetrafluoroethylene-PTFE dispersive emulsions, and got composite modified emulsions with the performances between binder and filler. It means PTFE was looked upon as a filler and was treated to be a binder, i.e, acrylates were used to modify PTFE and the emulsions with performance of binder were gotten. The preparation process of the experiment was simpler and low cost. The performance of the modified emulsion made great promotion, especially on weather resistance and stain resistance. It could form film ambient. It was a novel and effective method to prepare fluoro-containing emulsions.Research works included the following contents:The acrylate emulsions were made of a fluoro-containing emulsifier and non-ionic surfactant OP-10. The self-made acrylate emulsions were of better stability and better performance and looks bright and plump. The principles to select materials and experiment conditions to prepare acrylate emulsions and PTFE/acrylate composite modified emulsions were inspected details. By the emulsion polymerization experiments, two kinds of modified composite emulsions were prepared.The emulsions were characterized and tested. Five independent ways but supplement each other were designed to prove the idea of experimental design. They included FTIR, TEM, granularity distributing, small seed polymerization and rheological change. All results indicated experiment-planning idea was doable. The structure of latex particles and composite modified mechanism both in macroscopic view and microscopic view were explored.The different properties of the products were tested. The influence of initial seed quantity, monomers quantities and their ratio, emulsifiers’ quantities, initiator quantity, experiment temperature etc on the emulsion performances was explored. The factors influencing polymerization stability were investigated. Finally, emulsifier quantity was determined to be 1.8%~1.9% and initial seed percentage was 14%~18%. Solid containing of composite modified emulsion was 40%-50%. The percentage of functional monomer was controlled below 3%. When prepared the second stage seed, normal swelling method was adopted. Stirring speed was controlled 120~250rpm and should be kept stable. APS was initiator and the ratio to total monomers quantity was 0.45 %~0.61 %.Rheological properties of emulsion products would influent that of coating products, so更多还原