【作者】 武步华；

【导师】 路福绥；

【作者基本信息】 山东农业大学 ， 应用化学， 2010， 硕士

【摘要】 农药水悬浮剂为多相粗分散体系,热力学稳定性和动力学稳定性均较差,成为制约农药水悬浮剂研究开发的瓶颈。农药水悬浮剂的热力学稳定性与其加工过程中使用的润湿分散助剂有关,研究农药水悬浮剂加工中润湿分散助剂的作用原理,对润湿分散助剂的研发和选择及解决农药水悬浮剂的热力学稳定性具有重要意义。本文对氟啶脲悬浮剂的润湿分散剂进行了筛选,在此基础上进一步研究了pH值、盐离子等因素对悬浮剂物理稳定性的影响,同时对氟啶脲悬浮剂的稳定机理进行了系统的研究。本论文主要进行了以下几方面内容的研究:1采用流点法对10%氟啶脲悬浮剂的润湿分散剂进行了初步筛选,在流点法筛选结果的基础上利用激光粒度仪测定粒径的方法对分散剂进行进一步的筛选。结果表明,农乳602、分散剂NNO、MOTAS均能加工成流动性好的氟啶脲水悬浮剂,采用优化组合法和粘度法最终确定了10%氟啶脲水悬浮剂的润湿分散剂:农乳602和MOTAS的比例为4:1,用量为0.8%。2在润湿分散剂筛选的基础上,通过zeta电位的测定和流变性的测定,系统地研究了pH值、盐离子等因素对氟啶脲悬浮液稳定性的影响。结果表明:（1）氟啶脲悬浮液的Zeta电势在实验pH范围内均为负值,随pH值的增加绝对值先增大后略有减小,在pH值为8.5附近绝对值最大。pH影响离子型聚合物分散剂在水溶液中的解离,从而影响其在悬浮剂中分散稳定作用的发挥。（2）不同盐离子的加入均对悬浮剂的Zeta电势产生影响。悬浮剂的Zeta电势随NaCl浓度的增大先增加后有所减小,随MgCl₂浓度的增加而一直增加,且在相同盐离子浓度下,MgCl₂的影响较为显著;NaCl、MgCl₂两种盐溶液的加入,均可增加氟啶脲悬浮液的粘度,但影响程度不同。在所研究的MgCl₂浓度范围内,悬浮剂的非牛顿指数n均小于1,且随浓度的增加略有降低。以上结果说明pH值及盐离子浓度均对氟啶脲悬浮剂的物理稳定性产生影响。3我们以聚羧酸盐类分散剂MOTAS为研究对象,通过红外光谱及紫外光谱分析,吸附等温线的测定,研究了分散剂与氟啶脲颗粒表面分子间作用力及其吸附性能。氟啶脲颗粒对MOTAS的吸附受很多因素影响,除了材料本身外,还受温度、pH值、盐离子的影响。红外光谱、紫外光谱说明,MOTAS分散剂在氟啶脲颗粒界面的吸附属于物理吸附,氢键和π-π共轭作用是分散剂分子与氟啶脲表面结合的重要作用力;MOTAS分散剂在氟啶脲表面的吸附可认为是单分子层吸附,可用Langmuir吸附等温式进行线性拟合,其饱和吸附量随温度的升高先增大后减小;pH值和盐离子均对分散剂的吸附产生影响,吸附量随pH值的升高先增大后有所减少,随盐离子浓度的升高吸附量先减小,最后趋于稳定;解吸附实验结果说明分散剂和氟啶脲颗粒表面之间存在较强的分子间作用力,进一步表明氢键和π-π共轭作用是分散剂分子与氟啶脲表面结合的重要作用力。更多还原

【Abstract】 Pesticide suspension concentrate for the multiphase coarse dispersed system, thermodynamic stability and kinetic stability were poor, as a proplem to the development of pesticide suspension concentrate. The thermodynamic stability of pesticides SC affected by the additive of wetting dispersant, study of the function principle of wetting dispersant in pesticide suspension concentrate is important for wetting dispersant additive and solution development and selection of the thermodynamic stability of the pesticide suspension concentrate. Dispersant of chlorfluazuron SC was selected,then the stability of chlorfluazuron SC effect with pH value, salt ions and other factors were studied,and the stabilization mechanism of hlorfluazuron SC were analyzed and discussed in this paper. The main research contents of this paper are as follows:1 Based on flow point method, dispersant of 10% chlorfluazuron SC were selected by laser particle size instrument.The results showed that chlorfluazuron SC added with 602, dispersing agent NNO and MOTAS had good flowability, the experiment were conducted by orthogonal test and viscosity measurement to select the proper dispersant and their dogase: 602 and MOTAS was 4:1, the dogase: was 0.8%.2 By Zeta potential measurement and rheological test, the influences of pH value and salt ions on the stability of chlorfluazuron SC were studied. The The results showed that :（1）The Zeta potential of suspension in the range of experimental pH values are negative,with the increase of the pH value, the absolute value of the Zeta potential first increases and then decreases slightly, and in the vicinity of PH 8.5 the maximum absolute value. The dissociation of ionic polymer dispersant in water affected by pH values, the stability of ionic dispersion affected by the dissociation of polymer dispersions in SC. （2）The addition of salt ions can influence the Zeta potential of the emulsion, Zeta potential of latex suspension with the increase of NaCl concentration first increased and then decreased slightly, with the increase of MgCl₂ concentration has increased, and The influences of MgCl₂ were more significant than NaCl at the same concentration; The addition of NaCl and MgCl₂ can increase the viscosity of chlorfluazuron SC, but the results different. In the studied range of MgCl₂ concentration, non-Newtonian index n of emulsion is less than 1, and decreased slightly with increasing concentration.3 Adsorption Characteristics of the dispersants MOTAS on the surfaces of chlorfluazuron particles were determinated respectively,and the dispersion stabilization mechanism of the suspension was discussed. The adsorption of dispersants MOTAS on the surfaces of chlorfluazuron particles impacted by temperature, pH and salt ions besides the properties of material. The results of IR and UV spectra showed that the adsorption of dispersant MOTAS on the interface of chlorfluazuron particle is physical adsorption, hydrogen bond andπ-πconjugation effect was the main acting force between dispersant molecules and the surface of chlorfluazuron. The adsorption of dispersant MOTAS on the interface of chlorfluazuron particle can be considered as a single molecular layer adsorption, and Langmuir adsorption isotherm can be used for nonlinear fitting, the adsorption capacity increases with temperature then decreased. The adsorption of dispersant impacted by pH value and salt ions, adsorption capacity of dispersant increased with pH value of the increase first and then decrease, with the increase of salt concentration adsorption first decreases and finally stabilize. Desorption experiments showed dispersants and chlorfluazuron particle surface there exists strong intermolecular forces, and further show that the hydrogen bonds andπ-πconjugate effect of dispersant molecules and the surface binding chlorfluazuron important force.更多还原