【作者】 王金；

【导师】 曾幸荣；

【作者基本信息】 华南理工大学 ， 高分子化学与物理， 2009， 博士

【摘要】 含氟丙烯酸酯聚合物由于具有独特的长链氟烷基结构,因而具有极低的表面自由能,能赋予基材良好的憎水憎油性。含氟丙烯酸酯的乳液聚合以水为介质,对环境无污染,被广泛应用于涂料、织物及皮革整理剂等领域。由于含氟单体价格高昂,人们希望在满足性能要求的同时,尽量减少氟单体的用量,因此如何在水分散体系中高效合成具有理想结构和性能的含氟共聚物有着重要的理论与现实意义。本论文采用了核壳乳液聚合、无皂乳液聚合以及乳液共混方法制备了储存性稳定、具有优良疏水疏油的含氟丙烯酸酯乳液,系统的研究了含氟乳液聚合过程的影响因素,并对乳胶膜的结构和性能进行了深入研究。论文的研究内容和成果包括如下四点:第一,采用阴-非离子型乳化剂磺基琥珀酸癸基聚氧乙烯(6)醚酯二钠(DNS-628),甲基丙烯酸十二氟庚酯(DFHMA)、丙烯酸六氟丁酯(HFBA)以及甲基丙烯酸三氟乙酯(TFEMA)为含氟丙烯酸酯单体,丙烯酸(AA)为功能单体,KPS为引发剂,通过半连续加料方式合成了含氟丙烯酸酯共聚乳液。研究了引发剂用量、乳化剂用量、功能单体用量和含氟单体用量对乳液聚合过程以及乳胶膜性能的影响。应用热重分析(TG)、透射电子显微镜(TEM)、傅立叶红外光谱仪(FTIR)和激光散射粒度分析等手段对乳液和乳胶膜进行了表征。发现选用具有较长含氟侧链的DFHMA为含氟单体时,制得的乳胶膜具有较优的表面性能,乳胶膜对水的接触角达到105.5°,对十六烷的接触角为75°,表面能为12.95 mN/m,吸水率为12.7%,具有很好的疏水疏油性能。乳液最佳的聚合条件是KPS用量为0.6wt%,DNS-628用量为3.5wt%,AA用量为1wt%,DFHMA用量为8wt%。X射线光电子能谱(XPS)表明含氟丙烯酸酯共聚乳液在成膜过程中,含氟组分会在乳胶膜-空气界面富集,形成具有氟元素浓度从乳胶膜-空气界面到乳胶膜-玻璃界面递减的梯度分布结构。第二,以烯丙氧基壬基酚聚氧乙烯(10)醚单磷酸(ANPEO10-P1)为反应型乳化剂,甲基丙烯酸全氟辛基乙酯(PFEA)为含氟丙烯酸酯单体,采用超声预乳化方式,通过预乳化-半连续加料方式合成出具有核壳结构的无皂含氟丙烯酸酯共聚乳液。探讨了核壳结构乳液聚合过程的影响因素。随着反应型乳化剂用量的增加,乳液的转化率增大,聚合稳定性先增大后减小。随着壳层中的含氟单体用量的增加,乳胶膜的对水接触角增大,耐水性提高,热稳定性提高。乳液最佳的聚合条件为:反应温度为70℃,KPS用量为0.35wt%,ANPEO10-P1用量为5wt%,PFEA用量为6wt%,滴加时间为3h。此条件下乳胶粒子大小为70nm,多分散指数为1.02。变角XPS表明核壳结构更有利于乳液成膜时含氟组分向乳胶膜表面富集,有效的降低了乳胶膜的表面张力,乳胶膜对水接触角达到109.5°,对十六烷接触角达到82°,具有优异的疏水疏油性能。第三,以PFEA为含氟丙烯酸酯单体,双丙酮丙烯酰胺(DAAM)为功能性单体,通过超声预乳化-半连续加料法合成了含有酮羰基的无皂核壳型含氟丙烯酸酯共聚乳液,并采用己二酸二酰肼(ADH)为交联剂,制备了粒子大小均匀、粒径分布窄,可室温交联的核壳型含氟丙烯酸酯共聚物乳液。研究了DAAM用量和PFEA用量对乳液聚合过程以及乳胶膜性能的影响。采用TG、FTIR、TEM、SEM以及激光粒度分析仪等手段对自交联含氟乳液及乳胶膜进行了表征。随着DAAM用量的增加,乳胶粒粒径变小,聚合物交联度增加,吸水率减小,热稳定性增大。核壳乳液聚合过程中,DAAM在壳聚合阶段加入可以显著提高乳液成膜后的交联度和耐水性。同时变角XPS分析表明,交联含氟乳胶膜中氟元素含量随着乳胶膜表面深度的增加呈梯度递减分布。第四,采用反应型乳化剂ANPEO10-P1为主乳化剂,含氟表面活性剂双(十三氟庚酯)磷酸铵(FSP)为助乳化剂,采用一次性投料法合成了无皂甲基丙烯酸三氟乙酯均聚物乳液(PTFEMA),并通过与丙烯酸酯共聚物乳液共混制备了具有良好疏水疏油性能的含氟共混乳液。研究了无皂甲基丙烯酸三氟乙酯均聚物乳液的反应条件以及乳液共混比例对共混乳液性能的影响。用DSC、TG、TEM、ATR和XPS等手段对共混乳液及乳胶膜进行了表征。FSP的引入提高了聚合乳液的稳定性,随着FSP用量的增加,凝胶率下降。乳液最佳的聚合条件为:反应温度为75℃,超声乳化时间为12min,KPS用量为0.6wt%,ANPEO10-P1用量为4wt%,FSP用量为0.4wt%,此时乳胶粒子平均粒径为69nm。随着PTFEMA在共混乳液比例的增加,乳胶膜对水对十六烷的接触角增大,表面能降低。当PTFEMA与PBA-MMA质量比为4:5时,共混乳液室温成膜后,对水的接触角达到94°,对十六烷的接触角达到64°。XPS分析表明,共混乳胶膜-空气表面的氟元素含量为7.9%,而乳胶膜-玻璃面的氟元素含量仅为0.9%,说明在共混乳液成膜过程中,小粒径且低表面张力的PTFEMA自组织向乳胶膜表面迁移,在乳胶膜-空气界面富集。更多还原

【Abstract】 The fluorinated polyacrylate has the extremely low surface energy because of unique long chain fluorinated alkyl structure, and it endows the substrate with good water and solvent resistance. In recent years, fluorinated polyacrylate emulsion with water as medium which is environmental friendly has attracted the increasing attention of many investigators. Fluorinated polyacrylate has a wide range of applications in surface coatings, such as water and oil repellency for textile, paper and leather. However, the relatively high market price of the fluorinated monomers restricts their practical applications. The challenge is how to minimize the amount of fluorinated compositions whereas the reasonable surface properties can be maintained. In this work, the fluorine-containing polyacrylate emulsion was prepared by core-shell emulsion polymerization, emulsifier-free emulsion polymerization and latex blending method. The preparation and characterization of the emulsion were studied, and the structure and properties of latex film were investigated. The main research contents and achievements are listed as following:Firstly, the fluorine-containing acrylate copolymer emulsion was synthesized by emulsion polymerization through semi-continuous method using DNS-628 as emulsifier, acrylic acid (AA) as functional monomer and dodecafluoroheptyl methacrylate (DFHMA) as fluorinated acrylate monomer. The effects of initiator amount, emulsifier amount, AA amount, DFHMA amount on the emulsion polymerization and properties of the latex film were studied. The latices and its films were characterized by using TG, TEM, FTIR, XPS and laser particle diameter analyzer. It is found that the latex film using DFHMA as fluorinated monomer has better surface properties, the water contact angle and cetane contact angle of the film is 105.5°and 75°respectively, while the water absorption is 12.7% and the surface energy of the film is 12.95mN/m simultaneously. The optimal polymerization condition is 0.6wt% KPS, 3.5wt% DNS-628, 1wt% AA and 8wt% DFHMA in this system, and XPS shows there is an enrichment of fluorine element on the film-air interface.Secondly, the soap-free fluorine-containing acrylate latices with core-shell structure were prepared by the pre-emulsification and semi-continuous polymerization method, using perfluorooctylethyl methacrylate (PFEA) as fluorinated acrylate monomer and monophosphoric acid allyloxy nonylphenoxy poly(ethyleneoxy)(10) ether (ANPEO10-P1) as reactive emulsifier. The effects of polymerization conditions on the conversion and polymerization stability were discussed in detail. The optimal polymerization condition is 70℃of polymerization temperature, 0.35wt% KPS, 5wt% ANPEO10-P1 , 6wt% PFEA and 3h of dropping time in this system, the average particle size of the latex is 70nm and the polydispersity is 1.02, and the water contact angle and cetane contact angle of the film is 109.5°and 82°respectively, while the water absorption is 8.8%. With the increasing of PFEA amount, the latex film shows higher water contact angle, better water-resistance and thermal stability. XPS analysis with different take-off angels proves that the fluorine concentration in the film has the tendency to extend into the film-air interface and occupy the air–film interface during the formation of the latex film. Compared to the latex film without core-shell structure, the latex film with core-shell structure shows higher fluorine concentration, which proves the core-shell structure benefit the enrichment of fluorine component at the film-air interface.Thirdly, the fluorine-containing acrylate latex with a core-shell structure was synthesized using perfluorooctylethyl methacrylate(PFEA) as fluorinated acrylate monomer and diacetone acrylamide(DAAM) as functional monomer by pre-emulsification and semi-continuous polymerization method. The ambient self-crosslinkable latex was attained with the addition of adipic dihydrazide(ADH) as crosslinking agent. The influence of DAAM and PFEA amount on the emulsion polymerization and film properties were studied. The latices and latices films were characterized by using TG, TEM, SEM, FTIR, XPS and laser particle diameter analyzer. The results show with the increasing of DAAM amount, the latex average particle size decreases, the crosslinking degree of the film increases, the water absorption of the film decrease and the thermal stability of the film increases. Compared to the addition of DAAM in core polymerization, the addition of DAAM in shell polymerization improves the crosslinking degree and the water-resistance of the latex film. Finally, the XPS analysis proves the enrichment of perfluoroalkyl groups on film-air interface.Finally, the soap-free latex of poly(trifluoroethyl methacrylate) was synthesized with ANPEO10-P1 as reactive emulsifier and phosphoric acid bis(tridecafluorooctyl) ester ammonium salt(FSP) as co-emulsifier. And by blending of poly(trifluoroethyl methacrylate) emulsion with polyacrylate copolymer emulsion, the fluorine-containing latex blends were prepared. The polymerization conditions of poly(trifluoroethyl methacrylate) latex and the influence of mass ratio of PTFEMA latex to PBA-MMA latex on the properties of latex blends were studied. The latex and latex blends were characterized by using TG, DSC, TEM, FTIR, XPS and laser particle diameter analyzer. The optimal polymerization condition of PTFEMA latex is 75℃of polymerization temperature, 12min of ultrasonic processing time, 0.6wt% KPS, 4wt% ANPEO10-P1 , and 0.4wt% FSP. With the increasing of PTFEMA mass ratio, the surface energy of the latex blend film decreases. When the mass ratio of PTFEMA to PBA-MMA is 4:5, the water contact angle and cetane contact angle is 94°and 64°respectively, showing good water-resistance and oil-resistance. XPS analysis indicates the fluorine content is 7.9% at the film-air interface and 0.9% at film-glass interface, which prove that the PTFEMA polymer has the tendency to transfer to the surface of the latex blend film during the film formation and the fluorine content enrich at the outer space of latex film.更多还原