摘要
甲氧基聚乙二醇甲基丙烯酸酯(MPEGMA1100和MPEGMA600)、丙烯酸(AA)、甲基丙烯酸(MAA)和2-丙烯酰胺基-2甲-基丙磺酸(AMPS)通过水溶液调节共聚合制备了一系列不同支链组成的聚羧酸系减水剂(PC),研究了支链组成对水泥净浆流动度、砂浆凝结时间和砂浆强度的影响。采用动态和静态光散射测定了PC的平均流体力学半径和均方旋转半径,初步探讨了水泥坍落度损失的机理。结果表明,PC在水泥颗粒表面形成了类似核壳结构的聚集体,它的空间位阻有助于提高保塌性;不同长度的支链之间存在协同效应,当MPEGMA1100和MPEGMA600物质的量比为1∶0.2时,综合分散性能最好。折固掺量为0.3%,水灰比0.29时,水泥净浆流动度最大到335 mm,120 m in保持在220 mm;相同掺量,砂灰比2.7时,水泥砂浆3 d、7 d、28 d的抗压强度和抗折强度,它的效果明显优于单一支链的减水剂和萘系高效减水剂(SNF)。
Polycarboxylate superplasticizer （PC） was synthesized with methoxy polyethylene glycol methacrylate （MPEGMA1100, MPEGMA600）, acrylic acid （ AA）, methacrylie acid （MAA） and 2- acrylamido- 2- methyl propane sulfoninc acid（AMPS） through copolymerization in aqueous solution. The influence of side chain composition on the fluidity of cement, setting time and strength of cement mortar were investigated mainly. Average gyration and hydrodynamic radii were, respectively, determined in saline conditions by static and dynamic light scattering experiments. The mechanism of slump loss was studied preliminarily. It indicated that, on cement particle surface, the superplasticizer might form a kind of stable dense aggregates which structure similar to core-shell, and the steric hindrance played an important role in controlling slump loss. It also indicated that there was a synergetie effect between long MPEG graft chains and the short ones like MPEG1100 and MPEG600, respectively, and this effect apparently improve the dispersion efficiency. When the molar ratio of MPEGMAll00 and MPEGMA600 was 1/0.2, it showed the better dispersion performance. When this superplasticizer dosage was 0.3% and water/cement ratio of 0. 29, the fluidity of cement mm after 120 min. Under the same dosage, mortar was significantly better than single chain of paste can attain as high as 335 mm and retain at 220 compressive strength and flexural strength of cement superplasticizer and SNF.
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2010年第4期815-819,833,共6页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金重点项目(20776079)
山东省自然科学基金(Y2006F25)
关键词
聚羧酸
减水剂
聚乙二醇
分散机理
polycarboxylate
superplasticizer
fluidity
strength
dispersion mechanism
