不同侧链长度比例对聚羧酸超塑化剂分散性能影响

Effects of Ratio of Different Side Chain Length on Dispersion of Polycarboxylic Superplasticizer

以自制的甲基烯丙基聚氧乙烯醚（n=18，29）（MAPEG）及其它烯类单体为原料，过硫酸铵为引发剂，合成了分子结构含不同长度侧链的新型聚羧酸梳型超塑化剂，用红外光谱对其结构进行了表征。考察了不同链长的MAPEG混合比（投料比）对超塑化剂分散和分散稳定性的影响，测定了掺加超塑化剂的水泥颗粒的ζ电位。结果表明，不同链长的MAPEG的混合比对超塑化剂分散及分散稳定性影响很大。当MAPEG混合比n18：n29=1：4处出现分散性和分散稳定性的最佳点，在超塑化剂掺量0．4％、水灰比0．29时水泥净浆流动度235mm，120min后流动度保持率为87％。吸附不同链长超塑化剂水泥颗粒的‘电位在掺量0．3％～0．5％增加较明显，0．5％以上，ζ电位增幅不大。

Novel comb-shaped polycarboxylic superplasticizer with different length of side chains in molecular structure was synthesized by using self made methyl allyl polyethenoxy ether （n =18, 29） and other vinyl monomers initiated by ammonium persulfate as raw materials and its structure was characterized by FTIR. Effects of mixed ratio of MAPEG （molar ratio） with different side chain length on dispersion and dispersing stability of superplasticizers was investigated, ζ potential values of cement particles absorbing superplasticizer were determined. Testing results showed that dispersion and dispersing stability of superplasticizer were much influenced by mixed ratio of MAPEG. Optimum mixed ratio of MAPEG appeared at ratio of n18 ： n29 = 1 ： 4. When addition of superplasticizer attained to 0.4% and water cement ratio 0.29, fluidity of cement paste reached 235 mm and fluidity retention after 120min was 87%. ζ potential values of cement particles absorbing superplasticizer increased obviously with dosage in the range of 0.3%-0.5% and a little increase over 0.5%.