【作者】 高玉华；

【导师】 王延吉；

【作者基本信息】 河北工业大学 ， 化学工艺， 2010， 博士

【摘要】 聚天冬氨酸（PASP）是一种可生物降解的环保型阻垢分散剂,但在阻垢分散和缓蚀性能上与其它类型阻垢分散剂还有一定的差距,使其应用受到了很大限制。为此,本文对聚天冬氨酸进行改性,在聚天冬氨酸的侧链上引入功能性基团来提高阻垢分散和缓蚀性能,旨在研制绿色环保型工业循环冷却水处理药剂。以提高阻垢分散性能为目标,利用天冬氨酸热缩聚产物聚琥珀酰亚胺（PSI）和天冬氨酸（ASP）、2-氨基乙磺酸（SEA）分别合成了两种聚天冬氨酸衍生物——羧酸基聚天冬氨酸衍生物（ PASP-ASP ）和同时含羧酸基和磺酸基聚天冬氨酸衍生物（PASP-SEA-ASP）,利用氨基酸等电点的性质以及氨基酸与茚三酮溶液的颜色反应,对合成的聚天冬氨酸衍生物进行了分离和提纯,并对其接枝率进行了测定,红外光谱法和元素分析法表征了两种聚天冬氨酸衍生物的结构。考察了不同原料摩尔比、不同反应温度和不同反应时间条件对产物接枝率的影响,优化出了聚天冬氨酸衍生物的适宜合成条件,反应机理为亲核加成-消除反应。研究了产物接枝率和阻垢性能、分散性能、缓蚀性能之间的关系,确定了不同基团在阻垢分散和缓蚀过程中各自所起的作用,结果表明:聚天冬氨酸分子结构中羧酸基的引入有助于阻垢性能和缓蚀性能的提高,而磺酸基的引入可大大提高分散性能,但阻垢性能降低。考察了不同用量、水温、水质硬度及时间等条件下对碳酸钙的阻垢性能,确定了阻垢率和缓蚀率随之变化的定量关系。通过动态模拟试验,研究了聚天冬氨酸衍生物的动态污垢热阻和动态阻垢率,静态和动态实验结果表明:在低加药量的情况下,分子结构中同时引入具有较好阻垢性能和分散性能的功能基团的聚天冬氨酸衍生物的动态污垢热阻小,加药量为0.5 mg·L^-1时,PASP-SEA-ASP的动态阻垢率达到了99.35 %;在高加药量的情况下,分子结构中仅引入具有较好阻垢性能的功能基团的聚天冬氨酸衍生物的动态污垢热阻小,加药量为1.5 mg·L^-1时,PASP-ASP的动态阻垢率达到了96.13 %以上。因为在加药量较小时,药剂中的磺酸基起到了分散作用,使得碳酸钙晶体不粘附于加热棒上,只是分散于水中,加大药剂含量时,磺酸基的比例也增加,使得羧酸基螯合Ca2+的作用减弱,形成的CaCO₃沉淀也增多,过多的CaCO₃沉淀粘附于加热棒上,动态阻垢率减小。利用扫描电子显微镜和红外光谱仪等技术对碳酸钙晶体进行了观察和分析,结合静态和动态的阻垢分散试验,当加入聚天冬氨酸衍生物后碳酸钙的形貌为球形的球霰石结构时,表现出优良的分散性能,当加入聚天冬氨酸衍生物后碳酸钙的形貌为类球形的球霰石结构时,表现出优良的阻垢性能。利用电化学阻抗测试系统和扫描电子显微镜对缓蚀机理进行了分析,电极吸附聚天冬氨酸衍生物后表面致密、有序性高,非极性基团-R一端在金属表面定向排列,形成疏水薄膜,阻止和腐蚀反应有关的电荷或物质转移,减缓了金属的腐蚀速率。更多还原

【Abstract】 Polyaspartic acid （PASP） is a kind of biodegradable environmentally friendly scale inhibition dispersing agents. Its performance of dispersion, scale and corrosion inhibition, however, is worse than the other scale inhibition dispersing agents. So it is important to improve its performance of dispersion, scale and corrosion inhibition by research on modified PASP. In this paper, functional groups are introduced in the side chain of PASP in order to develop an environmentally friendly and high-efficient water treatment chemical use in industrial circulating cooling water system.For the purpose of increasing scale inhibition rate, two polyaspartic acid derivatives （PASP-ASP and PASP-SEA-ASP） were prepared from polysuccinimide （PSI） that was thermal condensation polymer of aspartic acid （ASP）, taurine （SEA） and ASP. The polyaspartic acid derivatives were separated and purified made use of property of isoelectric point of amino acid and color reaction of amino acid and ninhydrin, and their grafting ratios were mensurated. The structure of polyaspartic acid derivatives were characterized by means of FTIR and elemental analyzer. The effect of the synthesis conditions, such as mole ratio of materials, reaction temperature and reaction time, on the grafting ratios of polyaspartic acid derivatives were studied, and the suitable synthetic reaction conditions were optimized. The mechanism of reaction was nucleophilic addition-elimination reaction. The relationships between the performance of scale inhibition, dispersion, corrosion inhibition and grafting ratios of polyaspartic acid derivatives were studied, Their respective action of different group on process of dispersion, scale and corrosion inhibition were researched. The results showed that the carboxylic acid group was introduced in molecular structure of PASP helped improvement of scale inhibition performance and corrosion inhibition performance, and the sulfonic acid group was introduced helped improvement of dispersive performance, but worsen performance of scale inhibition. In addition, the scale inhibition performance of polyaspartic acid derivatives on calcium carbonate was investigated under the conditions of different dosages, water temperature, water hardness and experiment time, and then the quantitative relationship between the scale and corrosion inhibition rate and the factors above mentioned was determined.The dynamic dirtiness resistance and the dynamic scale inhibition rate of polyaspartic acid derivatives were investigated by dynamic experiments. Both the static and dynamic experiments showed that the dynamic dirtiness resistance of polyaspartic acid derivative that functional groups of possess scale inhibition and dispersion performance were introduced in molecular structure of PASP synchronously was less under less dosage, and the dynamic scale inhibition rate could reach 99.35 % under PASP-SEA-ASP 0.5 mg·L^-1; And the dynamic dirtiness resistance of polyaspartic acid derivative that functional groups of possess scale inhibition performance was introduced in molecular structure of PASP only was less under bigger dosage, and the dynamic scale inhibition rate can reach 96.13 % under PASP -ASP 1.5 mg·L^-1. Because sulfonic acid group take dispersive effect that made the calcium carbonate crystallite not to adhere to heating stick and to disperse in water under less dosage. The proportion of sulfonic acid group was bigger that made function of chelating Ca2+ ion of carboxylic acid group was weaken and then the formed CaCO₃ deposition was more, so overmany CaCO₃ deposition should adhere to heating stick and the dynamic scale inhibition rate could minish when dosage was bigger.The calcium carbonate crystal samples were characterized by SEM and FTIR techniques and the results of the static and dynamic experiments showed that the crystal form of calcium carbonate was global vaterite after polyaspartic acid derivative was added that possessed excellent dispersive performance, and the crystal form of calcium carbonate was similar global vaterite after polyaspartic acid derivative was added that possessed excellent scale inhibition performance. The mechanism of corrosion inhibition was studied by EIS and SEM techniques and the results showed that the face of electrode that absorbed polyaspartic acid derivative was dense and high ordered, and nonpolar group that was–R was directional arranged on the surface of metal and hydrophobe membrane was formed, and that prevent from transfer of charge or matter that was relevant to corrosive reaction. Then that slowed corrosion rate of metal down.更多还原