【摘要】 以N-乙烯基吡咯烷酮为单体、过氧化氢为引发剂,在水溶液中进行自由基聚合得到聚乙烯基吡咯烷酮(PVP)。然后以PVP替代传统的聚醚类大分子单体,以m(AA)∶m(PVP)=0.68、m(APS)∶m(PVP)=0.041、m(SHP)∶m(PVP)=0.056为原料配比,聚合得到一种具有新型分子结构、减水和分散作用良好的PVP型聚羧酸减水剂(PVP-PC)。红外、核磁和GPC分析结果表明,PVP已经参与反应并成功接枝到聚丙烯酸主链上。性能测试结果表明,当PVP-PC掺量为0.30%时,水泥净浆流动度达304 mm;同时,该减水剂在水泥中的吸附量高达103.48 mg/g,远高于普通聚醚侧链聚羧酸系减水剂的71.48 mg/g。更多还原

【Abstract】 PVP type polycarboxylate superplasticizer(PVP-PC) with novel molecular structure was synthesized by using polyvinylpyrrolidone(PVP)instead of the traditional polyether macromolecule monomer. Polyvinylpyrrolidone was prepared by free radical polymerization in aqueous solution with N-vinyl pyrrolidone as monomer and hydrogen peroxide as initiator. When the weight ratio of raw materials was m(AA)∶m(PVP)=0.68,m(APS)∶m(PVP)=0.041,m(SHP)∶m(PVP)=0.056,the PVP type polycarboxylate superplasticizer embraced good dispersion and water reduction. The results of IR,NMR and GPC show that PVP has participated in the reaction and were successfully grafted onto the main chains of polyacrylic acid. The results also show that when the dosage of PVP-PC was 0.30%,the cement paste fluidity was 304 mm,meanwhile,the adsorption amount of the PVP-PC in cement was up to 103.48 mg/g,which was much higher than that of conventional polyether side chains polycarboxylate superplasticiz-ers(71.48 mg/g).更多还原