温度对丙烯酸酯类聚羧酸超塑化剂性能的影响

摘要

系统研究了丙烯酸酯类聚羧酸超塑化剂(PAAE)在水泥体系中的分散性能、吸附行为以及分子结构稳定性与温度的依赖关系,并探讨了分散与吸附和水解速率的关系.结果表明:PAAE的初始分散能力随温度升高逐渐增加,但分散保持能力随温度的升高而降低,显示出很强的温度依赖性;PAAE在水泥颗粒表面的吸附量随温度的升高逐渐增加,30℃条件下出现吸附量明显下降的现象.PAAE在碱性环境下发生部分水解反应,水解率随温度升高而增加.水解反应使聚合物分子结构遭到严重破坏,这直接影响PAAE的分散性能.%Effects of temperature on dispersability, adsorption behavior and chemical structural stability of acrylate-type polycarboxylate superplasticizer (PAAE) were investigated systematically and the relationships between these properties and temperature were further analyzed. The results show that the initial dispersability of PAAE increases as the temperature increases, but the time of dispersion retention gradually decrease with increasing temperature. The adsorption amount of PAAE increases as the temperature increase below 30 °C but decrease significantly when the temperature up to 30 °C. The ester bond in PAAE is partly broken in the alkaline environment and at higher temperature. The hydrolyzed ratio of PAAE increases with increasing temperature. This hydrolysis of acrylate-type polycarboxylate has directly an adverse effect on dispersion properties.