反相乳液聚合法制备两性聚羧酸高聚物 MPEGAA/AA/DAC及其性能研究

以自制大分子单体聚乙二醇单甲醚丙烯酸酯(MPEGAA)、丙烯酸(AA)和自制丙烯酰氧乙基三甲基氯化铵(DAC)为原料,通过反相乳液聚合技术,制备了两性聚羧酸高聚物MPEGAA/AA/DAC.采用傅里叶红外光谱法(FTIR)、核磁共振碳谱(¹³C NMR)方法对两性聚羧酸高聚物的结构和组成进行了表征,考察了反相乳液聚合条件对单体转化率及90 min内水泥净浆流动度保持率的影响,并对添加了质量分数为0.20%两性聚羧酸高聚物MPEGAA/AA/DAC混凝土的性能进行了探讨.结果显示,当选用单体质量分数为40%,n(AA)/n(MPEGAA)=3,n(DAC)/n(MPEGAA)=0.5,占油相质量3.5%的Span-80/Tween-80为乳化剂,油水体积比V_o/V_w=0.45,占单体总质量1.5%的2,2’-偶氮二异丁腈(AIBN)为引发剂,引发温度为50 ℃,反应时间为6 h时,制得的两性聚羧酸高聚物具有优越的保塑性能和较高的早期抗压强度性能.

Preparation and performance of amphoteric polycarboxylate polymer MPEGAA/AA/DAC by inverse emulsion polymerization

An amphoteric polycarboxylate polymer of MPEGAA/AA/DAC was synthesized with self-made macromonomer methoxyl polyethylene glycol acrylate(MPEGAA), acrylic acid(AA), and self-made acryloyloxyethyltrimethyl ammonium chloride(DAC)by inverse emulsion polymerization. The characteristics amphoteric polycarboxylate polymer were studied by means of fourier transform infrared spectroscopy(FTIR)and carbon-13 nuclear magnetic resonance spectrocopy(¹³C NMR). Effects of inverse emulsion polymerization conditions on the monomer conversion rate and retention percentage of fluidity of cement paste in 90 min were investigated. In the meantime, the performance of concrete with amphoteric polycarboxylate polymer of MPEGAA/AA/DAC by the mass fraction of 0.20% were studied. The results show that the amphoteric polycarboxylate polymer with good dispersion retention and high early compressive strength can be obtained at the monomer mass concentration of 40%, the [n(AA)/n(MPEGAA)] mole ratio is 3, the [n(AA)/n(MPEGAA)] mole ratio is 0.5, the dosage of emulsifiers Span-80/Tween-80 is 3.5%(mass fraction), the volume ratio of oil to water(V_o/V_w)is 0.45, the dosage of initiators 2,2’-azoisobutyronitrile(AIBN)is 1.5%(mass fraction), the initiation temperature is 50 ℃ and the reaction time is 6 h.