【作者】 沈娟；

【导师】 黄啟良；

【作者基本信息】 中国农业科学院 ， 农药学， 2008， 硕士

【摘要】 为探索不同因素对农药悬浮剂(SC)贮存物理稳定性的影响,指导农药悬浮剂配方组份的选择,构建优良的农药悬浮体系,本文以40%噻嗪酮和50%多菌灵悬浮体系为研究对象,通过国内外几种主要的SC专用、新型润湿分散剂的性能、农药悬浮剂的加工工艺、悬浮体系的流变特性等方面,研究了农药悬浮体系的贮存物理稳定性。润湿分散剂的选择是影响农药悬浮剂贮存物理稳定性的主要因素,本文采用流点法和尝试法相结合的方式,结合增粘剂的筛选,通过测定悬浮剂的主要技术指标,对几种润湿分散剂进行性能评价。结果表明,羧酸盐类表面活性剂在40%噻嗪酮悬浮剂的研究中各项性能优越,尤其是与烷基磺酸盐类的WLNO UK分散剂配合使用,能有效提高制剂的各项指标性能。烷基酚聚氧乙烯醚磷酸酯类表面活性剂、烷基磺酸盐类等表面活性剂在50%多菌灵悬浮剂中应用时均对温度表现出较为敏感的现象,相关制剂在热贮条件下粘度上升。特别是不同厂家生产的同种原药,对表面活性剂的使用影响也不同,使得悬浮体系的稳定性也存在很大差异。通过比较立式、卧式两类砂磨机和不同粒径、材质的研磨介质对悬浮剂研磨效率及贮存物理稳定性的影响。结果表明,立式砂磨机AO6314比其它两种立式砂磨机的研磨效率显著提高;卧式砂磨机比立式砂磨机研磨能力提高2倍以上。研磨介质对研磨效率也具有显著影响,粒径小的玻璃珠比粒径大的玻璃珠研磨效率更高,粒径相同的玻璃珠与氧化镐珠之间的研磨效率没有显著差异。不同的加工工艺主要影响了悬浮制剂的颗粒粒径,并且最终影响了制剂的贮存物理稳定性。利用流变仪,研究了不同增粘剂、不同分散剂对50%多菌灵悬浮体系流变特性的影响。结果发现,影响流变特性的主要原因是分散剂的结构性质不同,以及分散剂与黄原胶等增粘剂的协同作用不同。TERSPERSE? 4896分散剂对悬浮体系的流变体为假塑性流体,与黄原胶协同作用不会改变该流体特性;TERSPERSE? 2210分散剂对悬浮体系流变随贮存时间的延长变化较大,特别是与黄原胶协同作用使得悬浮体系由假塑性流体向膨胀性流体转变;SOPROPHOR SC分散剂也使得悬浮体系随贮存时间由假塑性流体向膨胀性流体转变,但是,加入适当的黄原胶或膨润土能减缓甚至抑制这种转变,这在悬浮体系流变机理中具有重要研究意义。目前,国内关于农药悬浮剂流变学研究,均为假塑性流体,还没有关于膨胀性流体的相关研究报道。假塑性流体在农药中的研究主要是各种流变参数与制剂贮存物理稳定性的相关性,本文在研究了这几项参数与制剂的贮存物理稳定性关系发现,稳定度St与同一悬浮体系的稳定性显示了一定的相关性,St值越大,悬浮体的贮存物理稳定性越好。而表观粘度、卡森屈服值、相对屈服值则无明显规律性。在此研究基础上首次提出了τx值(假塑性流体向宾汉流体转变的临界值),实验结果表明τx值大小与制剂的贮存物理稳定性成正相关。农药悬浮剂是一个相当复杂的体系,不同农药原药的性能差异很大,在具体农药悬浮剂产品的研制中,仍要通过实验对有关助剂配方、工艺进行筛选。不过,能从机理上对农药悬浮剂的贮存物理稳定性有所认识,并结合开展分散助剂在农药原药上吸附的研究,农药悬浮剂的流变学研究,定会有助于我国对农药悬浮剂这一新剂型的研制、开发。更多还原

【Abstract】 To explore different factors on the physical storage stability of the pesticide suspension concentrate, guide the choice of pesticide component, construct excellent pesticide suspension system, the physical storage stability of 40% buprofezin SC and 50% carbendazim SC were studied by the performance evaluation of several major novel dedicated wetting-dispersant with the research of processing technic and rheology property.The choice of wetting-dispersant was the major factor in affecting the suspension physical storage stability. Several wetting-dispersants were estimated by mensurating the major technical parameters of SC, Integrating flow point method and trial method with the choice of thicken agents. The results showed that, the performances of carboxylate surfactant were excellent in 40% buprofezin SC, especially used with alkane sulfonate WLNO UK. The surfactants of alkylphenol ethoxylates, alkane sulfonate and so on were sensitive to temperature in 50% carbendazim SC. Viscosity of the relative suspension increased in hot storage. In particular,the impact of surfactant was different in the same type of TC produced by different manufacturers.Comparing the effects of different vertical, horizontal sand mills and different particle size, material grinding mediums to suspension grinding efficiency and physical storage stability, the result showed that,the vertical sand mill AO6314 was more efficient than other two vertical sand mills. And the horizontal sand mill was more efficient than vertical sand mills. The grinding medium also had significant impact on grinding efficiency. The smaller beadings were more efficient than the larger, and there was no significant difference between beading and pickax bead, a heavy metal. The difference of processing technic affected the physical storage stability of SC, due to the different particle size created in suspension.The influence of different thicken agents and dispersants to 50% carbendazim SC was tested by rheometer. The results showed that, The molecular structure of different dispersants and the different synergistic reactions between dispersant and xanthan gum (XG) were the main reasons of the influence of the flows. The rheological models of SC with dispersant TERSPERSE? 4896 were pseudoplastic fluids, which didn’t changed with XG. The rheological models of suspension with dispersant TERSPERSE? 2210 had great changes along with the storage, pseudoplastic fluid change into dilatant fluid especially with the synergistic reaction of XG. The suspension with dispersant SOPROPHOR SC had the same change, but this transform can be slow up or even restrained through adding appropriate quantity of XG or bentonite. The research had significance in rheological mechanism. By now, there isn’t any report about dilatant fluid in pesticide suspension system, except pseudoplastic fluid.The pseudoplastic fluid studied in pesticide SC was about the pertinences between rheological parameters and the physical storage stability of formulation. We tested the pertinences and found that, in the same SC system, stability index St had a certain pertinence to physical storage stability. The St larger, the stability better. And the relative viscosity, casson yield value, relative yield value had no pertinence with physical storage stability. Base on the research, we put forwardτx(the critical value of pseudoplastic fluid changing into bingham fluid), and the result of the test showed that there was a positive correction betweenτx and physical storage stability of formulation.The pesticide suspension concentrate is a very complex system. there is considerable variability in the performance of different TC. In the research of pesticide SC, we should still filtrate correlative adjuvants and processing technic by lots of experiments. But the knowledge of physical storage stability of pesticide SC got in mechanism must be helpful to the development of pesticide SC in our country, combing with the adsorption research of dispersant in pesticide TC and the rheology.更多还原