丙烯酸浓度对聚羧酸减水剂聚合速率的影响及反应级数

Effect of Acrylic Acid Concentration on the Polymerization Rate of Polycarboxylate Superplasticizer and Reaction Order

以异戊烯基聚氧乙烯醚(TPEG)为大单体、丙烯酸(AA)为小单体、过硫酸铵(APS)为引发剂、甲基丙烯磺酸钠(MAS)为链转移剂,采用一次投料水溶液自由基共聚法合成聚羧酸减水剂(PCE)。改变酸醚比即AA初始浓度合成PCE,分析了AA浓度对PCE聚合速率的影响,并进一步拟合了AA的反应级数。研究表明,随着PCE反应进程的推移,AA浓度减小、AA转化率增大。PCE聚合速率随着AA初始浓度的增大而增加,当AA初始浓度由0.2376 mol/L升至0.9008 mol/L时,聚合速率由1.3×10^(-4)mol/(L·s)升至4.8×10^(-4)mol/(L·s),AA的反应级数为0.9554。

The polycarboxylate superplasticizers(PCE) were synthesized by one-time feeding and aqueous solution free radical copolymerization with isopentenyl polyoxyethylene ether(TPEG) as macromonomer,acrylic acid(AA) as small monomer,ammonium persulfate(APS) as initiator,and sodium methacrylate sulfonate(MAS) as chain transfer agent.By desiging different acid-ether ratios for changing the initial concentration,the influence of AA concentration on the polymerization rate of PCE was investigated,further fitted the reaction order of AA.The results show that with the progress of the PCE reaction,the concentration of AA decreases and the conversion rate of AA increases.With the initial concentration of AA increaseing from 0.2376 mol/L to 0.9008 mol/L,the polymerization rate increases from 1.3 × 10^(-4)mol/(L · s) to 4.8 × 10^(-4)mol/(L · s),the polymerization rate is increased with the increasing concentration of AA,and the kinetic experiment shows that the reation order of AA is 0.9554.