【作者】 张保华；

【导师】 路福绥；

【作者基本信息】 山东农业大学 ， 农药学， 2013， 博士

【摘要】 农药悬浮剂以其高效、安全、经济、环境友好等优点相对于其他传统剂型有更大的应用优势，但是长期以来农药悬浮剂的稳定性问题一直制约着制剂的发展。本文以30%苯醚甲环唑悬浮剂为研究对象，在构建其稳定体系的前提下，从吸附、沉降、流变等方面系统研究了分散剂、增稠剂等助剂对悬浮体系稳定性的影响，同时对苯醚甲环唑制剂在不同植物叶片上的润湿性能进行了评价。主要研究结果如下：1.30%苯醚甲环唑悬浮剂配方的确定（1）本研究通过对润湿分散剂、增稠剂筛选，结合正交设计方法对配方进行优化，得到了30%苯醚甲环唑悬浮剂的稳定配方（质量百分比）：苯醚甲环唑30%，聚羧酸盐分散剂D1001为3.5%，润湿剂888为3.5%，Tanemul Ps54为2.5%，防冻剂丙三醇3%，增稠剂分别为黄原胶0.08%+硅酸镁铝1.2%或黄原胶0.1%+SM-A870.1%，去离子水补足100%。制剂各项指标符合国标规定，热贮后粒径仍保持在1-2μm，悬浮率仍能达到90%以上。（2）30%苯醚甲环唑悬浮剂是通过湿法研磨制备的，悬浮剂的粒径大小、粒度分布与加工时间、氧化锆珠的粒径大小和用量有很大关系。通过对30%苯醚甲环唑悬浮剂砂磨工艺的研究，确定选用1.2mm小粒径氧化锆珠，物料总质量与氧化锆珠体积比为1:1.8，研磨时间为2h时，得到的悬浮剂颗粒粒径保持在1-2μm，而且粒度分布较窄，悬浮剂能保持良好的物理稳定性。2.30%苯醚甲环唑悬浮剂稳定性能研究本研究在30%苯醚甲环唑悬浮剂配方基础上，探讨了聚羧酸盐分散剂及温度、pH值等影响因素对悬浮剂体系稳定性能的影响，具体研究结果如下：（1）通过研究不同粒径的苯醚甲环唑颗粒对聚羧酸盐分散剂D1001的吸附性能，发现吸附表现为Langmuir吸附，而且苯醚甲环唑颗粒粒径小于1250目时，吸附量最大；在温度为25-55℃范围内，吸附量会随着温度的升高先增大后减小，在35℃时吸附量最大；而在pH值3-11范围内，吸附量也表现为先增大后减小的趋势，且在pH值为7时吸附量最大，分散剂D1001在苯醚甲环唑颗粒表面的吸附一级动力学显示在120min时吸附达到平衡，其吸附速率K1为0.0605min-1。（2）通过研究聚羧酸盐分散剂D1001对苯醚甲环唑悬浮剂稳定性能的影响，发现在添加量为4%时悬浮体系的粒径、跨度、黏度、沉降体积均达到最小值，而悬浮率达到最大值。3.不同增稠剂对苯醚甲环唑悬浮剂流变影响在基础配方30%苯醚甲环唑悬浮剂的研究基础上，研究黄原胶、海藻酸钠、SM-A87等悬浮助剂对苯醚甲环唑悬浮剂体系流变性能的影响，结果显示添加以上悬浮助剂的体系均显示出剪切稀化的假塑性特征，尤其是黄原胶和SM-A87的加入表现显著。本论文首次系统研究了深海细菌胞外多糖SM-A87在苯醚甲环唑悬浮剂体系中的流变特性，研究发现SM-A87可在苯醚甲环唑悬浮体系中形成网状结构，而且随着SM-A87添加量的增加，网状结构强度增加，稠度系数KH及屈服值τH增大，体系表现出剪切稀化的假塑性特征。在25-55℃温度范围内，悬浮体系均显示剪切稀化的假塑性特征，而且随着温度的升高，其剪切稀化现象减弱，体系粘度降低，其黏度活化能E为27.26kJ/mol，说明体系流变性能对温度有一定依赖性；而pH值对悬浮体系的流变性影响比较复杂，随着pH值的增大，稠度系数KH减小，而流变指数n增大，但都小于1，说明体系虽然保持假塑性特征但有减弱趋势；而NaCl对体系的影响并不显著，体系仍保持剪切稀化的假塑性特征。4.黄原胶与SM-A87、硅酸镁铝的协同效应研究为了进一步探讨黄原胶/SM-A87、黄原胶/硅酸镁铝在30%苯醚甲环唑悬浮剂中的助悬机理，论文从流变学方面系统研究了两个复配体系的协同效应以及影响因素，从而进一步指导增稠剂复配体系在苯醚甲环唑悬浮剂中的应用。（1）黄原胶与SM-A87的复配体系研究结果表明，当黄原胶与SM-A87以质量比1:1复配时具有一定的协同增效作用，具有显著的“剪切稀化”假塑性特征。通过考察二者增效复配体系在不同的温度、pH值和无机电解质条件下的流变性能，发现复配体系的流变性受温度影响较小，在25-55℃范围内，仍然保持明显的剪切稀化的假塑性特征；而复配体系的流变性能受pH值影响较为显著，随着pH值的增大，其屈服值τH、稠度系数KH明显增大，流性指数n也明显减小；无机电解质NaCl对SM-A87与黄原胶复配体系流变影响研究发现，即随着盐离子浓度的增加，屈服值、稠度系数KH减小，而流性指数n增大，复配体系假塑性特征减弱。（2）硅酸镁铝与黄原胶的复配研究发现，硅酸镁铝与黄原胶用量比为13.7︰1时，具有一定的协同增效效应；对复配体系影响因素的研究发现，增效复配增效体系随着pH值和温度的升高，屈服值和稠度系数K呈现减小趋势，流性指数n则逐渐增大，说明复配体系假塑性特征减弱；而随着NaCl添加浓度的增大，增效复配体系呈现稠度系数K增大，流性指数n减小的趋势，假塑性特征增强。5.苯醚甲环唑悬浮剂在亲水、疏水植物叶片上润湿性能评价研究选用基础配方30%苯醚甲环唑悬浮剂，通过添加有机硅助剂，并与市售10%苯醚甲环唑微乳剂比较，探讨了三个制剂配方在亲水植物黄瓜叶片和疏水植物甘蓝叶片的润湿性能。研究发现，三种配方药剂的临界胶束浓度均接近或低于其田间有效剂量浓度，稀释药液表面张力分别为51.6mN/m，38.9mN/m，25.5mN/m，均能在亲水植物黄瓜叶片上润湿，其中添加了有机硅助剂的悬浮剂发生流失现象，在疏水植物甘蓝叶片上，30%苯醚甲环唑悬浮剂药液不能润湿，发生滚落现象。结果说明，30%苯醚甲环唑悬浮剂润湿性能与自身推荐剂量浓度、药液临界胶束浓度、植物叶片临界表面张力密切相关。更多还原

【Abstract】 Pesticides suspension concentrate (SC) has the advantages of biological efficacy, safety,economic and environment-friendly over many other traditional formulations. However, issueof SC stability has restricted the development of formulation for a long time. In this paper,stabile suspension system of30%(w/v) difenoconazole was constructed. The effects ofdispersants, thickeners on the adsorption, sedimentation and rheology of suspension systemwere studied. The wetting property of different difenoconazole formulation on leaves ofdifferent plants were evaluated. The main results were as follows:1. Determination of30%difenoconazole SC formulationThe formulation of difenoconazole SC was optimized with the orthogonal design method.The optimum formula of30%(weight percent) difenoconazole SC were difenoconazole30%,D10013.5%,8883.5%, tanemulps542.5%, XG0.08%+aluminum magnesium silicate1.2%or XG0.1%+SM-A870.1%, glycerol3%, and fill water to100%. The particle sizemaintained1-2μm, with a suspension rate of more than93%after heat storage, all the otherindex were in accorded with the requirements of SC.30%difenoconazle SC was prepared by wet-grinding method. The particle size andparticle size distribution of formulation were closely related to the processing time and thediameter and amount of zirconium oxide beads. The results of sand rubbing study suggestedthat good stability of the suspension concentration with narrow particle size distribution couldbe obtained at the zirconia bead diameter of1.2mm, the mass ratio of the material withzirconia beads volume of1:1.8, and a grinding time of2hours. The resulted particle size ofsuspension maintained at1-2μm.2. Study on the stability of30%difenoconazole SCOn the basis of30%difenoconazole SC formula, the influence of dispersant and factorsof temperature and pH on the stability of suspension system were investigated. Specificresults were as followed:（1）Adsorption of dispersant D1001on the surface of difenoconazole of different particlesize were determined, the results showed that the adsorption expressed as the Langmuir model,The adsorption amount reached the maximum at the particle size of less than1250mesh.During a temperature range of25-55℃, the adsorption amount had a trend of first increasing and then decreasing with the increasing temperature, and the maximum adsorption wasobtained maximum at the temperature of35℃. Similar trend was found within the maximumadsorption at pH of7. Kinetics of interaction between D1001and difenoconazole showedbetter agreement with lagergren first order kinetics, the adsorption capacity reached themaximum within120min, and with the adsorption rate K1of0.0605min-1.（2）By adding of different amount of the dispersant D1001, it is found that the particlesize, span, viscosity, sedimentation volume of the suspension system reached their minimumvalues, and while the suspension rate got the maximum value when4%dispersant D1001wasadding.3. On the basis of30%difenoconazole SC formula, effect of Xanthan gum, sodiumalginate, and SM-A87as suspension additives, on the rheological behavior of prepareddifenoconazole SC was evaluated. The suspension systems with all above additives havepseudoplastic of “shear-thinning” characteristics, among which Xanthan gum and SM-A87played more significant roles.In this paper, the rheological property of expolysaccharide secreted by a deep-seamesophilic bacterium in difenoconazole suspension was studied systematically for the firsttime. The results indicated that SM-A87formed a network structure in the suspension system,and this network structure enhanced with the increase of the SM-A87addition. Theconsistency coefficient KHand yield value τHof suspension increased correspondingly, andexhibiting “shear thinning” characteristics of pseudoplastic fluid. The effect of temperature onthe suspension with SM-A87showed significant pseudoplasticity in range of25-55℃. The“shear thinning” property weakened and the viscosity reduced with the increasingtemperature. The corresponding viscosity activation energy E is27.26kJ/mol. Resultsindicated that the suspension system of SM-A87was dependent on the temperature. Effect ofpH on the difenoconazole suspension concentrates with SM-A87was more complex,consistency coefficient of suepesnion KHdecreased and rheological index “n” increased withthe increasing pH. But both KHand “n” were less than1, suggesting that the systemmaintained pseudoplastic characteristics with a decreasing trend. The SC added with NaClmaintained the “shear thinning” property of pseudoplasticity, but not significantly changedwith the NaCl concentration.4. The synergistic characteristics of rheological properties of Xanthan gum/SM-A87andXanthan gum/aluminum magnesium silicate were studied, in order to guide the application ofthickening agent system in difenoconazole SC. (1) The complex system of xanthan gum with SM-A87was studied. A strong synergisticeffect was observed when the mass ratio of Xanthan gum and SM-A87was1:1. The systemwas obvious pseudoplastic fluid with shear-thinning property, and the viscosity wassignificantly increased. The rheological behavior of complex system of Xanthan gum withSM-A87was less affected by the temperature with apparent shear-thinning pseudoplasticcharacteristics in the range of25to55℃. The effect of pH on the mixed system was moresignificant, the consistency coefficient KHand yield value τHincreased with the increasing ofpH, but rheological index “n” decreased markedly. Effects of inorganic electrolyte NaCl onthe rheology of SM-A87and xanthan gum seemed more complicated, the coefficient KHandyield value τHincreased and rheological index “n” decreased with the increase of saltconcentration, and the pseudoplastic characteristics weakened.(2) Compounds of magnesium aluminum silicate and xanthan gum were also investigated.Synergistic effect on viscosity has been found when magnesium aluminum silicate andxanthan gum reached a ratio of13.7:1. With the increasing of pH, the consistency coefficientKHand yield value τHdecreased, while the rheological index “n” increased. As for theinfluence of temperature, pseudoplastic characteristics of the system decreased with theincrease of temperature, indicating from the decreased consistency coefficient K and yieldvalue τHdecreased, and the gradually increased rheological index “n”. in the matter ofinorganic salt NaCl influence, consistency coefficient K increased and rheological index “n”decreased with the increasing NaCl mass fraction.5. Wetting properties evaluated of difenoconazole SC on leaves of hydrophilic andhydrophobic plantsThe wetting properties of30%difenoconazole SC and with organosilicon wetting agent,10%difenoconazole ME on the hydrophobic plant cabbage and hydrophilic plant cucumberleaves were investigated. The critical micelle concentration(CMC) of three formulations arewere close or blow to its effective concentrations, and surface tension of30%difenoconazoleSC is51.6mN/m,10%difenoconazole ME38.9mN/m, and SC withorganosilicon wetting agent25.5mN/m. three formulations have good wetting properties onthe cucumber leaves, and formulation adding organosilicon wetting agent occurred drainphenomena; but30%difenoconazole SC could not wet the cabbage leaves and rolled downfrom leaves. The results showed that wetting property30%difenoconazole SC was closelyrelated to recommended dose concentration, CMC and the critical surface tension of plant.Itcan be seen from the results, for the hydrophilic plant,30%difenoconazole SC can reach thecritical surface tension, and wetting in leaf distribution, while for the hydrophobic plant, it is necessary that wetting agent added in the formulation to reduce the surface tension and achieve betterwetting effect.更多还原