【作者】 张磊；

【导师】 钟秦；

【作者基本信息】 南京理工大学 ， 化学工艺， 2008， 硕士

【摘要】 聚天冬氨酸（PASP）是近年来国内渐渐兴起的一种化工产品,其最大特点是无毒。聚天冬氨酸进入环境中完全能生物降解,不破坏生态环境,是公认的绿色聚合物和水处理剂的更新换代产品。研究了微波法制备绿色阻垢剂聚天冬氨酸,并对合成反应的影响因素进行了研究,表征了合成的产品,对其阻垢性能进行了研究。以马来酸酐和氨水为原料,在一定的微波辐射强度下进行缩合得到聚琥珀酰亚胺（PSI）,然后在NaOH水溶液作用下水解成聚天冬氨酸。整个过程避免了气体氨的使用,优化了合成工艺。对合成条件和水解条件进行了单因素的研究。利用正交实验方法得到最佳合成工艺条件为:原料摩尔比氨/马来酸酐为1.2,微波辐射功率为900W,微波辐射时间为12min。实验的单程平均转化率达到71.7%;最佳水解条件为:水解温度为60℃,水解时间为60min,NaOH的浓度为10mol/L,单程水解率达到51.2%,相对分子质量为3500左右。对上述条件合成的产品进行了红外光谱表征和热重性能分析。红外光谱的特征峰表明所合成的产品中含有酰胺基、羧酸基团,与相关文献进行了比较,表明合成的产物为聚天冬氨酸。热重分析表明聚天冬氨酸热稳定性好,是一种可应用于高温400℃以下的水处理系统的阻垢剂。研究了聚天冬氨酸的阻垢性能。结果表明聚天冬氨酸具有良好的阻垢性能,阻垢剂聚天冬氨酸的浓度在60mg/L即可达到良好的阻垢性能,聚天冬氨酸的分子中含有-COOH和-NHCO-两种官能团,-COOH是阻CaCO₃晶体粒子的表面电荷密度,增加了粒子间的相互排斥,从而降低了CaCO₃结晶速度,使其悬浮在水中无法沉淀下来,从而增加了聚天冬氨酸对CaCO₃的阻垢效果;同时也对CaSO₄、BaSO₄的阻垢性能进行了研究:PASP对CaSO₄、BaSO₄两种溶液的阻垢性能区别有限。在聚天冬氨酸的阻垢实验中,通过阻垢剂的加入,研究了混合溶液中电导率的变化。分析了PASP阻垢效果的影响因素,并对聚天冬氨酸阻CaCO₃垢后形成微量沉淀进行了XRD谱图分析,从CaCO₃晶体结构和晶体外貌进行分析,研究了聚天冬氨酸抑制CaCO₃结垢机理。更多还原

【Abstract】 Polyaspartic acid（PASP） is a kind of scale inhibitor and polymer of amino acids which has attracted much attention of domestic and international researchers. There is no phosphor in pasp,it is not poisonous and can be totally biologic decomposed in the environment. The polyaspartic acid（PASP） polymer can be obtained by hydrolyzing PSI. the use of the ammonia gas was avoided. The react condition was optimized.All factors of the synthesizing and hydrolyzing were studied. The best preparation condinion was:the ratio MA:AM=1.2,the microwave radiation is 900W,and the time of microwave radiation is 12min.The average conversion rate attained71.7% on this condition. The best hydrolyzing factors was: hydrolyzing temperature 60℃, hydrolyzing time is 60 min,concentration of NaOH is 10mol/L.The average conversion rate attained 51.2% on this condition,and the relative molecular weight is about 3500.The IR and TG test were carried out for the product synthesized on above condition. The characyeristic peaks indicated there were amido and carboxyl groups in the molecule. Also the chart was compared with the consulted one and it proved the product was PASP. The TG analyses indicated that it was considered as a kind of water treatment medicine that can be applied at high temperature up to 400℃in water system.The scale inhibiting performance of PASP on CaCO₃ was investigated. Its mixture dosage were 60mg/L,the scale inhibiting performance was good respectively. The scale inhibiting performance of PASP on CaSO₄、BaSO₄ was investigated. The study showed that PASP was also suitable for high calcium ion. There was little difference between scale inhibiting performance of PASP on CaSO₄、BaSO₄.By quantitatively analyzing the equilibriumc oncentrations of Ca²⁺ and CO₃^2- in a super-saturated CaCO₃ solution,determining the CaCO₃ crystal structure. For PASP inhibiting the formation of CaCO₃ scale,the reasons that better scale-inhibiting performance of PASP than those of polyacrylic acid and hydrolyzed maleic anhydride had been studied.更多还原