两步聚合法制备水性双组分聚氨酯用丙烯酸水分散体

发布时间：2018-03-28 04:39

本文选题：水性　切入点：丙烯酸分散体　出处：《湖南大学》2010年硕士论文

【摘要】：本论文采用一步溶液聚合和两步溶液聚合的方法合成了羟基丙烯酸树脂,通过中和成盐的方式制备了羟基丙烯酸水分散体。通过粒径分布、热储稳定性测试比较了两种不同方法对羟基丙烯酸水分散体性能的影响。研究了制备过程中混合溶剂比例、中和剂的种类以及中和度对水分散体的黏度、粒径、热储稳定性的影响。本论文在新的羟基丙烯酸树脂水分散体制备方法上有创新。 (1)本文利用自由基聚合原理,以苯乙烯(ST)、丙烯酸丁酯(n-BA)、甲基丙烯酸异冰片酯(IBOMA)、丙烯酸(AA)、甲基丙烯酸-β羟乙酯(p-HEA)为反应单体,过氧化醋酸叔戊酯(TAPA)为引发剂,十二硫醇为链转移剂,在丙二醇丁醚(PnB)溶剂中溶液聚合。采用一步加料和两步加料分别制备了丙烯酸树脂。两步加料方式中前一步和后一步所用的原料种类相同,但亲水性单体的质量分数在后一步中比前一步高。通过对比分析一步聚合和两步聚合制备的羟基丙烯酸水分散体的性能以及其对应的涂膜性能的,发现两步聚合制备的丙烯酸树脂端羧基含量更高,相同中和度情况下,更多的羧基可被胺中和；且由两步聚合树脂中和分散后制备的丙烯酸水分散体比一步聚合的具有更均匀的粒径分布、更好的热储稳定性,其对应的涂膜具有更好的耐水性能。优选的两步聚合制备的羟基丙烯酸水分散体具有以下性能：固含量为36%,黏度为2000-5000 mPa-s (23℃),平均粒径为96.22nm,热储稳定性为30天以上。将该羟基丙烯酸水分散体与固化剂以-NCO/-OH为1.5：1固化成膜,所得涂膜具有优异的附着力、柔韧性、抗冲击性,硬度2 H,光泽度90%及良好的耐水性。 (2)研究了丙二醇丁醚(PnB)和丙二醇甲醚醋酸酯(PMA)混合溶剂中不同PMA含量对水分散体黏度以及热储稳定性的影响,确定了最佳的混合溶剂比：PMA/PnB= 2/3。分析了丙烯酸含量大小对水分散体的热储稳定性的影响,实验结果表明在一定的范围内羟基丙烯酸水分散体的热储稳定性是随着酸含量的增加而增加的。本文还研究了中和剂对水分散体的粒径的影响,比较了N,N-二甲基乙醇胺(DMEA)、三乙胺以及DMEA:三乙胺1：1(摩尔比)三种中和剂对水分散体的粒径、热储稳定性的影响,实验结果表明三乙胺作为中和剂比DMEA得到的水分散体的粒径大,基于这一点,可考虑通过混合胺的比例来调节本分散体系的粒径大小。比较分析了5种水分散体Zeta电位的大小以及热储稳定性能,发现Zeta电位的绝对值越大其分散体系稳定性越好的理论并不适用于本体系。
[Abstract]:In this paper, hydroxy acrylic resin was synthesized by one-step solution polymerization and two-step solution polymerization. Hydroxy acrylic acid aqueous dispersion was prepared by neutralization and salt formation. The effects of two different methods on the properties of hydroxy acrylic acid aqueous dispersions were studied. The ratio of mixed solvents, the type of neutralizer and the neutralization degree on the viscosity and particle size of the aqueous dispersions were studied. The effect of heat storage stability. In this paper, the preparation method of new hydroxy acrylic resin aqueous dispersion has been innovated. (1) in this paper, using the principle of free radical polymerization, the reactive monomers of styrene, butyl acrylate, isobornyl methacrylate (IBOMAA), acrylic acid (AA), 尾 -hydroxyethyl methacrylate (尾 hydroxyethyl methacrylate), and tert-amyl peroxide (TAPA) were used as initiators, and tert-amyl peroxide (TAPA) was used as initiator. Acrylic resin was prepared by solution polymerization of dodecyl mercaptan in propanediol butyl ether (PnB) solvent. Acrylic resin was prepared by one-step feeding and two-step feeding respectively. The type of raw materials used in the first step and the latter step in the two-step feeding method were the same. However, the mass fraction of hydrophilic monomer was higher in the latter step than in the first step. The properties of the hydroxy acrylic acid aqueous dispersion prepared by one-step polymerization and two-step polymerization and the corresponding film properties were analyzed. It was found that the content of carboxyl terminal of acrylic resin prepared by two-step polymerization was higher, and more carboxyl groups could be neutralized by amine at the same neutralization degree. The acrylic water dispersion prepared by neutralization of two-step polymerization resin has a more uniform particle size distribution and better thermal storage stability than that of one-step polymerization. The hydroxy acrylic acid aqueous dispersion prepared by two-step polymerization has the following properties: solid content is 36, viscosity is 2000-5000 mPa-s / m, average particle size is 96.22 nm, and storage stability is 30 days. The hydroxy acrylic acid aqueous dispersion and curing agent were solidified to form a film with -NCO / -OH as 1.5: 1, The film has excellent adhesion, flexibility, impact resistance, hardness 2 H, gloss 90% and good water resistance. The effects of different PMA contents on viscosity and thermal storage stability of aqueous dispersions in mixed solvents of propylene glycol butyl ether (PnB) and propylene glycol methyl ether acetate (PMA) were studied. The optimal ratio of mixed solvent to PMA / PnB = 2 / 3 was determined. The effect of acrylic acid content on the thermal storage stability of water dispersions was analyzed. The experimental results show that the thermal storage stability of hydroxy acrylic acid water dispersions increases with the increase of acid content in a certain range. The effect of neutralizer on the particle size of water dispersions is also studied in this paper. In this paper, the effects of three neutralizers, NN- dimethylethanolamine, triethylamine and DMEA: triethylamine 1: 1 (molar ratio) on the particle size and thermal storage stability of water dispersions were compared. The experimental results showed that triethylamine as neutralizer was larger than that obtained by DMEA. Based on this, the particle size of the dispersion system can be adjusted by the ratio of mixed amine. The Zeta potential of five kinds of water dispersions and the stability of heat storage can be compared and analyzed. It is found that the higher the absolute value of Zeta potential, the better the stability of the dispersion system.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TQ316.33

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