非离子聚丙烯酰胺絮凝剂对减水剂分散性能的影响

Effect of Nonionic Polyacrylamide Flocculant on Dispersibility of Water Reducer

本文选用非离子聚丙烯酰胺絮凝剂和不同侧链长度、酸醚比的聚羧酸减水剂、萘系减水剂,通过试验研究聚丙烯酰胺与减水剂之间的相互作用及对减水剂分散性能的影响。研究结果:随聚丙烯酰胺含量增加,减水剂的初始分散性能和保持性能均随之下降,而萘系减水剂所受影响较小;随聚羧酸侧链长度增加,聚羧酸减水剂的初始分散性能和保持性能下降严重;随聚羧酸酸醚比增加,各种聚羧酸减水剂的初始分散性能和保持性能受聚丙烯酰胺的影响差距不大;聚羧酸减水剂先吸附于水泥颗粒上,侧链再与聚丙烯酰胺通过氢键相互作用、缠结,从而降低了减水剂的空间位阻效应,随水泥水化更易被水化产物覆盖。

Nonionic polyacrylamide flocculant,polycarboxylic acid superplasticizer and naphthalene series superplasticizer with different side chain length and ratio of acid to ether were selected to study the interaction between polyacrylamide and superplasticizer and the influence on the dispersion of superplasticizer.The results were found:with the increase of polyacrylamide content,the initial dispersion and retention properties of water reducing agent decreased,but naphthalene series water reducing agent was least affected.With the increase of side chain length of polycarboxylic acid,the initial dispersion and retention properties of polycarboxylic acid superplasticizer decreased more seriously.With the increase of acid-ether ratio of polycarboxylic acid,the initial dispersion and retention properties of polycarboxylic acid superplasticizers were not significantly affected by polyacrylamide.Polycarboxylic acid superplasticizer was first adsorbed on cement particles,and then side chain interacted with polyacrylamide through hydrogen bond and entanglement,thus reducing the steric hindrance effect of the superplasticizer.With the hydration of cement,it was easier to be covered by hydration products.