PEGMMA-MA-IA-SMAS四元共聚减水剂的合成研究

Study on synthesis of tetra-copolymer superplasticizer based on PEGMMA-MA-IA-SMAS

以PEG(聚乙二醇)、MA(马来酸酐)、IA(衣康酸)和SMAS(甲基丙烯磺酸钠)为共聚单体,制备PEGMMA(马来酸聚乙二醇单酯)-MA-IA-SMAS四元共聚减水剂;然后将其用于混合土配方中,并以水泥净浆流动度为考核指标,采用单因素试验法优选合成减水剂的最优方案。结果表明:当减水剂中n(PEG)∶n(MA)∶n(IA)∶n(SMAS)=1∶3.8∶0.5∶1.0、酯化温度为105℃、酯化时间为4 h、w(引发剂)=12.5%(相对于单体总质量而言)、w(催化剂)=4%(相对于PEG和MA总质量而言)、聚合温度为80℃和聚合时间为7.5 h时,合成的减水剂和改性混凝土[w(减水剂)=0.33%]具有相对较好的综合性能;此时,水泥净浆初始流动度(278 mm)相对最大,并且混凝土减水率为28.6%、含气量为2.1%以及28 d压缩强度为49.6 MPa。

With PEG（polyethylene glycol）,MA（maleic anhydride）,IA（itaconic acid） and SMAS（sodium methyl allylsulfonate） as comonomers,a tetra-copolymer superplasticizer based on PEGMMA （polyethylene glycol monoester maleic acid）-MA-IA-SMAS was prepared. Then,with fluidity of cement paste as evaluation index and adding superplasticizer into concrete formula,an optimal project of synthesizing superplasticizer was preferred by singlefactor experiment. The results showed that the synthesized superplasticizer and modified concrete with 0.33% superplasticizer had relatively better combination property when molar ratio of n （PEG） ：n （MA） ：n （IA） ：n （SMAS） was 1：3.8：0.5：1.0 in superplasticizer,esterification temperature and time were 105 ℃ and 4 h respectively,mass fractions of initiator and catalyst were 12.5% in total monomers and 4% in PEG and MA respectively,polymerization temperature and time were 80 ℃ and 7.5 h respectively. Here,the initial fluidity（278 ram） of cement paste was relatively maximum,the water-reducing rate of concrete was 28.6% ,the gas content was 2.1% ,and the compressive strength at 28 d was 49.6 MPa.