【作者】 陶梅香；

【导师】 唐林生；

【作者基本信息】 青岛科技大学 ， 化学工艺， 2009， 硕士

【摘要】 长期以来,合成洗涤剂一直使用三聚磷酸钠(STPP)作为助洗剂,虽然效果很好,但对生态环境造成了严重破坏,引起水体“富营养化”,从而导致水质恶化,水生物大量死亡。因此,从上个世纪七十年代开始许多国家相继颁布法令、法规实行禁磷、限磷。因而开发无磷助洗剂已成为洗涤剂行业研究的热点。聚羧酸盐是新一代的无磷助洗剂,目前国内外研究得较多的主要是聚丙烯酸盐和丙烯酸-马来酸的共聚物盐(MA-Co-AA)。它们具有去污力较强、抗硬水能力好、无毒等优点,但助洗性能不及三聚磷酸钠,且降解性不好,因而在环境中长期积累也会引起环境问题。因此,开发助洗性能更好、可降解性好的聚羧酸盐具有重要意义。许多的研究结果表明,聚羧酸盐的助洗效果与其分子链中的羧基含量有关,羧基含量越高,电荷密度越大,螯合分散性能就越好。因此,通过与含两个羧基的马来酸酐单体共聚,可以提高聚羧酸盐的助洗效果。但马来酸的两个吸电子羧基分别与两个双键碳原子相连,形成对称结构,致使其聚合活性低,在共聚物中的量比不能太大,因而助洗性能的提高受到限制。衣康酸也是含两个羧基的单体,但为非对称结构,其中一个羧基通过亚甲基与双键碳相连,因而聚合活性较高。因此,以它为共聚单体,可向聚羧酸链中引入更多的羧基,因而有可能制得助洗性能更好的聚羧酸盐。另外,衣康酸聚合物具有良好的生物降解性。因此,衣康酸-丙烯酸共聚物(IA-Co-AA)可能成为更为环境友好的助洗剂。为此,本论文对IA-Co-AA的合成及助洗性能进行了研究。对采用水溶液聚合工艺合成IA-Co-AA进行了研究,并详细考察了各种工艺参数的影响,并与MA-Co-AA和IA-Co-MA-Co-AA进行了比较。研究结果表明,单体配比对IA-Co-AA的螯合力影响较大,随IA用量增加,螯合力增加,但IA用量过大时,因聚羧酸的分子量太小,单个聚羧酸分子所含电荷较少,螯合力反而下降;过硫酸铵用量对聚合物的特性粘度有较大的影响,过硫酸铵用量增加,特性粘度显著降低,即聚合物的分子量显著降低。反应温度对聚合物特性粘度有较大的影响,随着反应温度升高,聚合物特性粘度下降。反应温度对单体的转化率有些影响,温度过低,引发剂分解慢,造成聚合不完全,单体转化率降低。温度过高,引发剂分解太快,造成部分自由基无效消耗,因而单体转化率也降低。IA-Co-AA的较佳条件是:反应温度为80～85℃,过硫酸铵用量为单体总质量的6.67%,IA占总单体的摩尔分数为22%,丙烯酸和过硫酸铵的滴加时间约为2.5h,保温时间为3.5h,总反应时间为6h。助洗性能研究结果表明,IA-Co-AA的去污力、抗污垢再沉积能力、钙皂分散力和对Ca2+的螯合力明显好于MA-Co-AA、IA-Co-MA-Co-AA和STPP;IA-Co-AA对CaCO3粉末的分散能力明显低于MA-Co-AA和IA-Co-MA-Co-AA,但好于STPP;IA-Co-AA的pH缓冲能力略大于MA-Co-AA和IA-Co-MA-Co-AA,明显高于STPP;IA-Co-AA的表面活性比MA-Co-AA和IA-Co-MA-Co-AA的低;IA-Co-AA,但它们均与LAS具有较好的协同作用,它们的存在能显著降低LAS溶液的表面张力;IA-Co-AA较易生物降解,而MA-Co-AA和IA-Co-MA-Co-AA较难生物降解。由此可见,IA-Co-AA是一种具有良好助洗性能的绿色助洗剂。更多还原

【Abstract】 For a long term,pentasodium tripolyphosphate(STPP) has been used as a detergent builder because of its good building properties. Unfortunately, its widespread application has cause the eutrophication of water systems and the destruction of the ecologic environment, which brings about the worsening of water quality and the huge death of aquatic living beings. Therefore, many countries have issued the laws and regulations to ban or limit using STPP since 1970s. As a consequence, it has become an important reseach topic to developing non-phosphate detergent builders.Polycarboxylates are the new generation of non-phosphate detergent builders where acrylic polymer and acrylic acid- maleic anhydride copolymer are studied extensively in domestic and abroad. They have many advantages such as excellent detergency, resistance to hard water and nontoxicity, but their balance building property is inferior to STPP. In addition, their degradability is poor, so they also can cause environmental problems because of their long-term accumulation in environment. Therefore, it is very important to developing polycarboxylates with better building properties and degradability as builders.Many research results show that the building properties of polycarboxylates are related to the carboxyl content in molecular chain. The higher the carboxyl content, the higher the charge density, then the better the chelating ability and dispersibility. Therefore, the detergent performance of polycarboxylates can be improved by copolymerization of acrylic acid with the maleic anhydride containing two carboxyls. However, the polymerization activity and its copolymerization ability of maleic anhydride with acrylic acid are very poor because of its symmetrical structure with two electron-withdrawing carboxyls connecting the two carbon atoms of the double bond respectively, which bring about the detergent performance of the AA-Co-MA isn,t very ideal. Itaconic acid (IA) also contains two carboxyl groups, but its polymerization activity and copolymerization ability with acrylic acid are better because of its asymmetrical structure with one electron-withdrawing carboxyl group bonding the carbon atom of the double bond. Therefore, it is likely that detergent performance of the AA-Co-IA is better that of the AA-Co-MA. In addition, polyitaconic acid (PIA) has better biodegradability, so PIA and its copolymers as detergent builders can be more friendly to the environment. For these reasons, the synthesis and building properties of the IA-Co- AA were studied in this paper.The synthesis of the IA-Co-AA by an aqueous polymerization process was studied by investigating detailedly process parameters on its synthesis and building properties , and compared with the MA-Co-AA and the IA-Co-MA-Co-AA .The results show that the monomer ratio has a great effect on the chelating ability of the IA-Co-AA which is increased firstly with the increased amount of IA, but lowered reversely in excessive amount of IA , which may be attributed to the reduction of the molecular weight of the copolymer and the charge number of the molecular chain. The loading of ammonium persulfate has a great effect on the intrinsic viscosity of the copolymers which is lowered significantly with the increased amount of ammonium persulfate, which may be attributed to the reduction of the molecular weight of the copolymers. Reaction temperature has also a greater influence on the intrinsic viscosity which is decreased with the increased reaction temperature. Reaction temperature has also an effect on monomer conversion which is lower in lower or higher temperature, which may be attributed to slow decomposition of the initiator which cause incomplete polymerization in lower temperature, and extremely quick decomposition which cause a waste of free radicals in higher temperature. The optimum technical conditions were confirmed:reaction temperature was 80℃～85℃, and the dosage of ammonium persulfate was 6.67% based on the weight of all monomers, and the molar percentage of itaconic acid was 22% based on all monomers,and the dripping time of acrylic acid and ammonium persulfate was 2.5 h,and holding time was 3.5 h and reaction time was 6 h.The results of building properties show that the detergency , anti-sediment ability, dispersibility for calcium soap and chelating ability of the IA-Co-AA is obviously better than the MA-Co-AA、the IA-Co-MA-Co-AA and STPP; The dispersibility of the IA-Co-AA for CaCO3 powders is obviously lower than the MA-Co-AA and the IA-Co-MA-Co-AA, but better than STPP;The buffering pH capacity of the IA-Co-AA is slightly larger than the MA-Co-AA and the IA-Co-MA-Co-AA , but obviously larger than STPP; The surface activity of the IA–Co-AA is lower than the MA-Co-AA and the IA-Co-MA-Co-AA , but All the three copolymers have a good synergism with sodium dodecyl benzene sulfonate (LAS), so that the surface tension of the LAS solution is lowered obviously in the presence of them; The biodegradability of the IA-Co-AA is good, but of the MA-Co–AA and the IA-Co-MA-Co-AA is poor. In a word,the IA-Co-AA is a green detergent builder with better building properties.更多还原