摘要
根据梳形共聚物分散剂侧链长度是控制水泥悬浮体分散保持性能的最关键因素,合成了系列具有不同侧链长度的梳形共聚物,研究了共聚物侧链长度对水泥浆体分散保持、吸附和水泥早期水化的影响规律,揭示了其作用机理.结果表明:当共聚物中主链羧酸基团和侧链摩尔比相同时,长侧链共聚物由于延缓了水泥早期水化,显示了优异的分散保持性能;当每克共聚物中羧基质量基本相同时,短侧链共聚物则由于卷曲的分子构象,被水泥颗粒吸附较慢,导致了其优异的分散保持性能.不同侧链长度的梳形共聚物分散保持性能受吸附行为、水化行为和空间位阻效应共同控制,且侧链长度和主链中羧基含量存在一个最佳平衡.
The length of the side chain in comb-like copolymer dispersants is the key parameter to control the dispersion stability of concentrated cement pastes.In this study,two different groups of comb-like copolymer dispersants with side chain lengths n ranging from 8 to 48 are synthesized and characterized.The effects of side chain length in comb-like copolymers on dispersability retention,adsorption behavior and early hydration behavior for fresh cement suspensions are investigated systematically to elucidate its mechanism of dispersability retention.When we keep the same molar ratio of carboxylic acid to carboxylic ester in comb-like copolymers,the longer side chain comb-like copolymers have better fluidity retention than the shorter ones due to the delaying early cement hydration of the former.When we keep the same weight fraction of carboxylic acid in comb-like copolymers,the polymers with shorter side chains show better fluidity retention than polymers with longer side chains because the former polymers may curl up,thus needing more time to be adsorbed on cement surface.These results indicate the adsorption behavior,early hydration behavior and steric hindrance together should be responsible for the dispersability retention of comb-like copolymers with side chain lengths.Such information also suggests that their exists a balance between the carboxylic acid contents in backbone and the length of the side chains.
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2010年第A02期138-143,共6页
Journal of Southeast University：Natural Science Edition
基金
国家重点基础研究发展计划(973计划)资助项目(2009CB623200)
江苏省建设厅资助项目(JGJH2009-11)
江苏省自然科学基金资助项目(2008507
2007722)
关键词
梳形共聚物
侧链长度
分散保持
早期水化
吸附
构象
comb-like copolymer
side chain length
dispersability retention
early hydration
adsorption
conformation
