PEGMMA-MA-IA-SMAS四元共聚减水剂的合成研究

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。

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

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 single-factor 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 mm) 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.