| 摘要: |
| 合成了一系列含有不同阴/阳离子基团摩尔比的两性梳形共聚物，研究了其对水泥浆体分散、分散保持、吸附和水泥早期水化的影响规律，并初步探讨了其作用机理.结果表明：主链中适当引入阳离子基团可改善水泥浆体的分散性能，进一步提高阳离子基团含量，吸附量增大，但水泥浆体的分散性能下降；共聚物分散保持性能随主链中阳离子基团含量增加而增强，其分散保持率和溶液中共聚物浓度呈负相关.两性梳形共聚物优异的分散和分散保持性能受吸附位置、吸附构象和早期水化的共同影响，且主链中阴/阳离子基团摩尔比存在一个最佳平衡值. |
| 关键词: 两性梳形共聚物(PMAP) 分散 分散保持 早期水化 吸附 机理 |
| DOI：10.3969/j.issn.1007 9629.2012.02.002 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划(973计划)项目(2009CB623205)；江苏省自然科学基金资助项目(2008507，2007722) |
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| Research on Effects and Mechanism of Amphoteric Comb Like Copolymers on Dispersion and Its Retention of Cement Pastes |
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RAN Qian ping, LIU Jia ping, ZHOU Dong liang, MAO Yong lin, YANG Yong
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State Key Laboratory of High Performance Civil Engineering Materials, Jiangsu Research Institute of Building Science Co., Ltd., Nanjing 210008, China
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| Abstract: |
| Amphoteric comb like copolymers with different molar ratios of anionic to cationic groups in main chain were synthesized and characterized. The effects of molar ratio of anionic to cationic groups in comb like copolymers on dispersion, dispersability retention, adsorption behavior and early hydration behavior in fresh cement suspensions were investigated systematically to elucidate the mechanism of copolymers. These results indicate that moderate incorporation of cationic groups into comb like copolymers improved the dispersability of cement pastes. However, when the content of cationic groups was further increased, as the adsorbed amount of amphoteric copolymers was increased, the dispersibility of cement pastes became worse. The dispersability retention of cement pastes was enhanced with the increase of cationic groups content in main chain of amphoteric copolymers. Besides, there is a negative correlation between the dispersability retention ratio and copolymer concentration in solution. The adsorption sites, adsorption conformation and early hydration behavior together should be considered to explain its dispersion and the dispersability retention of cement pastes with amphoteric copolymers. In addition, there exists an optimal balance in the molar ratios of anionic to cationic groups in backbone of comb like copolymers. |
| Key words: amphoteric comb like copolymer(PMAP) dispersion dispersability retention early hydration adsorption mechanism |
