PVP型聚羧酸减水剂的合成与性能研究

Study on synthesis and properties of PVP type polycarboxylate superplasticizers

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。

PVP type polycarboxylate superplasticizer （PVP-PC） with novel molecular structure was synthesized by usingpolyvinylpyrrolidone （PVP）instead of the traditional polyether macromoleeule monomer. Polyvinylpyrrelidone was prepared by freeradical polymerization in aqueous solution with N- vinyl pyrrolidone as monomer and hydrogen peroxide as initiator. When theweight 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 polyear-boxylate superplastieizer embraced good dispersion and water reduction. The results of IR, NMR and GPC show that PVP has par-tieipated in the reaction and Were successfully grafted onto the main chains of polyaerylic acid. The results also show that whenthe dosage of PVP-PC was 0.30%,the cement paste fluidity was 304 ram, meanwhile,the adsorption amount of the PVP-PC in ce-ment was up to 103.48 mg/g, whieh was mueh higher than that of eonvantional polyether side chains polyearboxylate superplastieiz-ers （71.48 mg/g）.