【作者】 崔静；

【导师】 滕厚开；

【作者基本信息】 河北工业大学 ， 应用化学， 2015， 硕士

【摘要】 聚丙烯酸钠分子中有羧酸根(-COO-),羧基官能团能与水中易形成垢的金属离子,例如Ca2+、Mg2+结合,从而起到阻垢分散作用。但是聚丙烯酸(钠)的分子量从几千到上百万,其性能不但与分子量大小有密切关系,而且还受分子量分布的影响,因此研究聚丙烯酸钠分子量及其分布与性能之间的关系具有重要意义。本文采用沉淀分级的方法,实现了对聚丙烯酸钠的均匀分级,并通过实验证明聚丙烯酸分子量及其分布对其性能有较大影响,作为碳酸钙阻垢剂的聚丙烯酸最佳相对分子质量范围为小于1900,并且分子量分布越窄其阻垢性能越好。作为对碳酸钙分散剂的聚丙烯酸钠相对分子质量Mn=3400,分布指数D=3.35时分散效果最佳;作为锌离子稳定剂,聚丙烯酸钠相对分子质量Mn=5200,分布指数D=3.35时对锌离子稳定效果最好。探索了聚丙烯酸不同合成体系,其中有机酸盐-异丙醇复合调聚体系、以次亚磷酸钠作为链转移剂体系效果较好,优化其工艺条件,合成出了低分子量窄分布的聚丙烯酸钠,并对聚合产物进行了结构表征和性能评价。以有机酸盐-异丙醇复合调聚合成聚丙烯酸,以正交试验法确定最佳聚合工艺为:单体浓度30%,滴加时间4h,聚合温度80℃,引发剂占单体质量12.5%、有机酸盐占单体10%,异丙醇占溶剂质量25%。在最佳条件下得到了相对分子质量1500,分子量分布指数1.60的聚丙烯酸钠,对碳酸钙的阻垢率能够达到88%左右。以次亚磷酸钠作为链转移剂合成聚丙烯酸,考察了引发剂用量、次亚磷酸钠用量、聚合温度对聚合反应的的影响,确定出最佳聚合工艺为:单体浓度占总重30%,滴加时间2.5h,聚合温度80℃,引发剂用量占单体质量比8%,次亚磷酸钠用量占单体质量比10%,聚合温度80℃。最佳条件下得到了相对分子质量1300,分子量分布指数1.80的聚丙烯酸钠,对碳酸钙的阻垢率能够高达90.0%。更多还原

【Abstract】 There is carboxylate radical(-COO-) in sodium polyacrylate molecular, the carboxyl functional groups combine with metal ions which are in the water easy to form scale,such as Ca2 +, Mg 2 +, and so as to achieve scale inhibition dispersing effect. But the molecular weight of sodium polyacrylate from thousands to millions, and its performance not only has close relation with the size of molecular weight, but also influenced by molecular weight distribution index, so the relationship between the sodium polyacrylate molecular weight and its distribution with the performance is of great significance.This article adopts the method of fractional precipitation, realized the uniform classification of sodium polyacrylate, and through the experiment proves that polyacrylic acid molecular weight and its distribution has a great influence on the performance, as the calcium carbonate scale inhibitor the best range of relative molecular mass of polyacrylic acid is less than 1900, and the molecular weight distribution is narrower the scale inhibition performance is better. As dispersing agent for calcium carbonate, when sodium polyacrylate molecular weight Mn = 3400, distribution index D = 3.35 dispersion effect is best; As the zinc ion stabilizer, sodium polyacrylate molecular weight Mn = 5200, distribution index D = 3.35 the stability of zinc ions is best.Explore different polyacrylic acid synthesis system, in which the organic acid salt- isopropyl alcohol compound telomeric system and sodium phosphite as the chain transfer agent system has the batter effect, optimize the process conditions, synthetic of low molecular weight of narrow distribution polyacrylic acid sodium, and the product structure characterization and performance evaluation are also studied.organic acid salt- isopropyl alcohol compound telomeric system synthesis polyacrylic acid, through orthogonal test to determine the best polymerization process as follows: monomer concentration 30%, dropping time is 4h, polymerization temperature 80 ℃, initiator accounting for 12.5% of monomer quality, organic acid salt accounted for 10% of monomer quality, isopropyl alcohol accounted for 25% of the solvent quality.Under the best conditions to get the polyacrylic acid sodium with relative molecular mass 1500, molecular weight distribution index 1.60, the scale inhibition rate for calcium carbonate can reach about 88%.Successively synthetic sodium polyacrylate with sodium hypophosphite as chain transfer agent, investigate the influence of dosage of initiator and sodium hypophosphite, temperature of polymerization on the polymerization, determine the best polymerization process is: concentration of monomer is 30% of the total weight, and dropping time is 2.5 h, the reaction temperature is 80 ℃, dosage of initiator is 8% of monomer mass ratio, dosage of sodium hypophosphite accounts for 10% of monomer mass ratio, polymerization temperature is 80 ℃, obtain the synthesis that relative molecular mass is 1300, molecular weight distribution index is around 1.80, the scale inhibition rate for calcium carbonate can reach about 90.0%.更多还原