摘要
采用不同分子量大单体合成一系列侧链长度与侧链密度基本相同、主链长度逐渐变化的聚羧酸减水剂(PCE)。采用凝胶色谱仪测定其分子量分布及未反应单体含量。结果表明:聚羧酸减水剂的最佳主链长度受侧链长度影响,侧链越长,达到最佳性能时所需主链长度越短;链转移剂用量对聚合溶液中有效聚合物含量也有影响,对于不同分子量大单体,链转移剂与大单体的摩尔比不宜超过0.30。通过对比有效聚合物等质量添加与等摩尔添加时性能的差异,分析了PCE"个体分子分散效能"与"整体分散效能",发现随主链长度增加,单个PCE分子分散效能出现先增加后降低的趋势,但对水泥水化抑制作用随主链长度增加而增强。
A series of polycarboxylate superplasticizers （PCE） with different side chain lengths, a fixed side chain density and gradually-decreased backbone length were synthesized. The molecular weight, the molecular weight distribution and the polymerization conversion ratio were measured by gel permeation chromatograph. The results reveal that the mole ratio of chain transfer agent to different macromonomers does not exceed 0.30 to avoid a low conversion rate. The appropriate backbone length is affected by the length of grafted side chain, and the shorter backbone length is appropriate for the longer side chain to achieve the better performance. By comparing different performances obtained from equimolar and equimass adding methods, we analyzed the solo molecular disperse efficiency and the comprehensive efficiency of PCE. It was found that the solo molecular performance increases when the backbone length increases, but the performance decreases after reaching the appropriate point. The retarding effect of PCE to cement hydration becomes more obvious when the main chain length increases.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2013年第11期1534-1539,共6页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金(51208012)
国际科技合作项目(S2011GR-0398)资助
关键词
聚羧酸减水剂
主链长度
水化
分散效能
作用机理
polycarboxylate superplasticizer
backbone length
hydration
disperse efficiency
action mechanism
