偶氮二异丁脒盐酸盐引发聚羧酸系减水剂的合成工艺研究

本文采用偶氮二异丁脒盐酸盐(AIBA·2HCl)引发烯丙基聚氧乙烯醚(APEG)与马来酸酐(MA),在水溶液中进行自由基共聚合成聚羧酸系减水剂,利用凝胶渗透色谱(GPC)探讨了聚合工艺条件对单体转化率的影响规律,并对该聚合物进行性能测试。结果表明:最佳聚合工艺条件为单体摩尔比MA:APEG=2.5:1,引发剂的用量为单体总质量的4%,聚合温度75℃,反应时间6h。合成的减水剂对水泥净浆具有良好的分散性和分散保持性。用其拌制混凝土,在保塌性能和混凝土的后期强度增强作用都要优于市售同类减水剂。

Polycarboxylate superplasticizers was synthesized in aqueous solution by radical copolymerization of allyl alcohol poly- oxyethylene （APEG） and maleic anhydride （MA） and was initiated by 2,2＂-azobis （2-methylpropionamidine） dihydrochloride （AIBA？2HCl）. Effects of synthesis process conditions on the conversion rate of comonomer were studied by gel-permeation chromatography （GPC）. The results show that the optimal synthesis conditions are the ratio of maleic anhydride（MA） and allyl alcohol polyoxyethylene（APEG） was 2.5： 1; the initiator dosage was 4% of the monomer weight; the reaction temperature was 75 ~C; the reaction time was 6 h. The polycarboxy- late superplasticizers on cement paste possess good dispersivity and retentivity.When mixing it with concrete, the slump retaining ability and the performance of late compressive strength of concrete enhancement are better than similar commercially available polycarboxylate superplasticizers.