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| Synthesizing and evaluation of chemically modified straw pulp lignin based water reducer |
1. School of Materials Science and Teehnology, Nanjing University of Teehnology, Nanjing, Jiangsu 210009, China; 2. School of Materials Science and Technology, Southeast University, Nanjing, Jiangsu 210096, China）
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Abstract Aimed at the chemical modification for straw pulp lignin, the solicitation oxidation and sulphonation processing parameters for preparation chemically modified straw pulp lignin plasticizer （MLP） were investigated. The characteristics of MLP were evaluated by measuring its IR spectrum, adsorbed amount on cement grains, zeta potential of cement and surface tension of MLP water solution. In addition, properties of concrete plasticized with MLP were tested. Experimental results indicate that a kind of lignosulphonate, which has a water reducing rate of 15.2% , with -OH and -SO3 groups, can be obtained by oxidation and sulphonating straw pulp lignin, and that MLP has better adsorption -dispersion ability to cement grains by electrostatic repulsion. MLP may reduce surface tension of water. The properties of concrete plasticized with MLP accord with Chinese standard. As a kind of high range water reducer, MLP may replace lignosulphonates and partially replace naphthalene sulphonated formaldehyde condensates used in concrete.
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2008, Vol. 29 
