磺化接枝淀粉减水剂的合成及其结构与性能研究
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摘要
以玉米淀粉(CS)为原料,甲基丙烯磺酸钠(SMAS)为磺化接枝单体,过硫酸铵为引发剂,在水相体系中合成磺化接枝淀粉(SMAS/CS),以水泥净浆流动度为评价指标,通过单因素与正交实验得到最佳合成工艺参数为:引发剂用量(占淀粉与单体质量总和) 7%,单体用量(占淀粉干基质量分数) 1. 5%,反应温度65℃,反应时间1 h。FTIR表明,SMAS/CS在1 209 cm~(-1)处出现了新的吸收峰,证明淀粉分子已成功引入磺酸基团。利用XRD和SEM对掺加了SMAS/CS的水泥净浆进行晶体结构与表面形貌表征,结果显示,水泥初期水化反应缓慢,表面结构更加紧凑致密。水泥净浆流动度测试表明,随着SMAS/CS添加量的增加,流动度先增后降,当添加量为水泥质量的0. 8%时,流动度达最大;凝结时间测试证明SMAS/CS对水泥净浆具有明显缓凝作用;抗压强度测试证明,SMAS/CS掺量为0. 4%时,抗压强度比相应龄期基准样明显增强。
Using corn starch( CS) as raw material,sodium methallyl sulfonate( SMAS) as sulfonated graft monomer and ammonium persulfate as initiator,sulfonated graft starch( SMAS/CS) was synthesized in aqueous system. Taking fluidity of cement paste as the evaluation index,the optimal conditions for preparing SMAS/CS by single factor and orthogonal experiment are amount of initiator( accounting for the sum of the mass of starch and monomer) 7%,amount of monomer( accounting for the mass fraction of starch dry basis) 1. 5%,reaction temperature 65 ℃ and reaction time 1 h. The molecular structure analysis was determined by Fourier transform infrared spectroscopy( FTIR),the test results showed that a new absorption peak of SMAS/CS appeared at 1 209 cm~(-1),which proved that sulfonate acid groups had been introduced into starch molecules successfully. The crystal structure and morphology of cement paste were characterized by X-ray diffraction( XRD) and Scanning electron microscopy( SEM),the test results showed that when the cement paste was mixed with SMAS/CS,the initial hydration reaction of cement was more slowly and the surface structure became more uniform and compact. The test results of fluidity of cement paste showed that with the increasing of the amount of SMAS/CS,the fluidity increased firstly and then decreased. The fluidity reached the maximum when the addition amount of SMAS/CS was 0. 8%( accounting for mass fraction of cement). The test results of setting time showed that SMAS/CS had a significant retarding effect on the cement paste. The test results of compressive strength showed that whenthe amount of SMAS/CS was 0. 4%,the compressive strength was significantly stronger than the reference sample at the corresponding age.
Using corn starch( CS) as raw material,sodium methallyl sulfonate( SMAS) as sulfonated graft monomer and ammonium persulfate as initiator,sulfonated graft starch( SMAS/CS) was synthesized in aqueous system. Taking fluidity of cement paste as the evaluation index,the optimal conditions for preparing SMAS/CS by single factor and orthogonal experiment are amount of initiator( accounting for the sum of the mass of starch and monomer) 7%,amount of monomer( accounting for the mass fraction of starch dry basis) 1. 5%,reaction temperature 65 ℃ and reaction time 1 h. The molecular structure analysis was determined by Fourier transform infrared spectroscopy( FTIR),the test results showed that a new absorption peak of SMAS/CS appeared at 1 209 cm~(-1),which proved that sulfonate acid groups had been introduced into starch molecules successfully. The crystal structure and morphology of cement paste were characterized by X-ray diffraction( XRD) and Scanning electron microscopy( SEM),the test results showed that when the cement paste was mixed with SMAS/CS,the initial hydration reaction of cement was more slowly and the surface structure became more uniform and compact. The test results of fluidity of cement paste showed that with the increasing of the amount of SMAS/CS,the fluidity increased firstly and then decreased. The fluidity reached the maximum when the addition amount of SMAS/CS was 0. 8%( accounting for mass fraction of cement). The test results of setting time showed that SMAS/CS had a significant retarding effect on the cement paste. The test results of compressive strength showed that whenthe amount of SMAS/CS was 0. 4%,the compressive strength was significantly stronger than the reference sample at the corresponding age.
引文
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[11]王立久,黄凤远,张鸿,等.纤维素基混凝土高效减水剂制备与应用研究[J].大连理工大学学报,2008,48(5):679-684.
[12] Crepy L,Petit J Y,Wirquin E,et al. Synthesis and evaluation of starch-based polymers as potential dispersants in cement pastes and self leveling compounds[J]. Cement and Concrete Composites,2014,45:29-38.
[2] Zhang D F,Ju B Z,Zhang S F,et al. The study on the synthesis and action mechanism of starch succinate half ester as water-reducing agent with super retarding performance[J]. Carbohydrate Polymers,2008,71(1):80-84.
[3] Plank J. Applications of biopolymers and other biotechnological products in building materials[J]. Applied Microbiology and Biotechnology,2004,66(1):1-9.
[4]孙红岩,韩洪燕,王晓平,等.改性木质素高效减水剂作用机理的研究[J].应用化工,2013,42(8):1370-1373.
[5] Vieira M C,Klemm D,Einfeldt L,et al. Dispersing agents for cement based on modified polysaccharides[J]. Cement and Concrete Research,2005,35(5):883-890.
[6]石从黎,李林涛,宋开伟.淀粉基减水剂的合成与性能研究[J].新型建筑材料,2011(4):65-68.
[7]赵平,严云,胡志华.改性淀粉作为混凝土缓凝减水剂的性能研究[J].混凝土与水泥制品,2012(7):1-5.
[8]程发,侯桂丽,伊长青,等.磺化淀粉开发用作新型减水剂的研究[J].精细化工,2006,23(7):711-716,720.
[9] Zhang D F,Ju B Z,Zhang S F,et al. The study on the dispersing mechanism of starch sulfonate as a water-reducing agent for cement[J]. Carbohydrate Polymers,2007,70(4):363-368.
[10]王田堂,严云,胡志华,等.氧化-醚化淀粉作水泥减水剂的制备及性能(二)[J].武汉理工大学学报,2011,33(1):60-63.
[11]王立久,黄凤远,张鸿,等.纤维素基混凝土高效减水剂制备与应用研究[J].大连理工大学学报,2008,48(5):679-684.
[12] Crepy L,Petit J Y,Wirquin E,et al. Synthesis and evaluation of starch-based polymers as potential dispersants in cement pastes and self leveling compounds[J]. Cement and Concrete Composites,2014,45:29-38.