改性草浆碱木素减水剂的制备与性能评价

Synthesizing and evaluation of chemically modified straw pulp lignin based water reducer

针对草浆碱木素化学改性,研究了引发氧化和磺化制备改性草浆碱木素减水剂(MLP)的工艺参数,通过测定MLP的红外光谱、MLP在水泥颗粒表面的吸附量、水泥ζ-电位、MLP水溶液的表面张力及掺MLP的水泥净浆流动性,对MLP进行了表征,并试验研究了掺MLP的混凝土性能.试验结果表明:通过对草浆碱木素进行氧化改性和磺化改性,可获得含有羟基、磺酸基等官能团的木质素磺酸盐减水剂,减水率达到15.2%;碱木素经改性后,表面活性提高,通过吸附-分散作用,降低水泥颗粒的ζ-电位,并可显著降低水的表面张力;掺MLP的混凝土性能符合高效减水剂国标要求.草浆碱木素经氧化和磺化改性后,不仅可代替木浆木质素磺酸盐使用,而且因其具有高效减水剂的性能指标,还可单独作为高效减水剂使用,或部分取代萘系高效减水剂.

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.