Study On Preparation And Physical And Chemical Stability Of 20%Fluopyram Suspension Concentrate

In this experiment,we mainly studied the mechanism of the influence of polyacid dispersants on the physical and chemical stability of 20%fluopyram suspension concentrate.Three new polycarboxylate dispersants,atlox metasperse 550S(550S),agrilan 700(A700)and atlox,were selected 4913(4913)screened the formulation of 20%fluopyram suspension concentrate,determined the best dosage and formulation of the suspension concentrate by measuring the fluidity,physical and chemical stability,particle size,dispersibility,suspension and effective component content of the preparation,and studied the adsorption behavior of the two dispersants on the surface of fluopyram technical particles on the basis of formula selection,through infrared spectroscopy The interaction force between the dispersant and fluopyram was characterized.The adsorption capacity and adsorption kinetics trend of the dispersant on the surface of the original drug were characterized by UV spectrophotometer.The influencing factors of the adsorption capacity of the dispersant on the surface of fluopyram particles and the rheological behavior of the suspension prepared by the three dispersants were studied In different shear rates,the changes of apparent viscosity and shear force reflect the rheological trend of the system,and the rheological data are fitted with mathematical model to characterize the fluid characteristics of the suspension system of fluopyram;the 20%fluopyram suspension concentrate is revealed from three aspects:formula selection,adsorption behavior of the suspension concentrate and rheological study of the suspension concentrate Stability mechanism.The specific research results are as follows:1.The wetting agent,dispersant,thickener and stabilizer in the suspension were screened by single factor test design.Finally,the formulation of fluopyram suspension concentrate was determined as follows:20%fluopyram,2%550S dispersant,2%EFW or 2.5%A700,2.5%EFW or 2.5%4913,1.5%EFW,0.2%xanthan gum,1%Indulin AT,3%ethylene glycol,0.5%SAG630,and 100%deionized water.All the 20%fluopyram suspension concentrates processed in the laboratory meet the standards of quality index and physical and chemical properties.2.FTIR and UV were used to analyze the adsorption force between fluopyram and three kinds of polycarboxylic acid dispersants 550S,A700 and 4913,and the factors influencing the adsorption capacity.The results showed that the adsorption between the three dispersants and fluopyram particles was physical adsorption,the main adsorption force was van der Waals force;the adsorption equilibrium concentration of 550S and A700 on the surface of fluopyram particles was consistent with the formula screening results,and the dispersant 4913 was inconsistent with the formula screening results.In the process of using three kinds of dispersants to process fluopyram suspension concentrate,the temperature should be 298K,the processing time should be more than 1.5h,and the pH of the system should be within the range of 6-7.Proper addition of NaCl can improve the adsorption capacity of the dispersant in fluopyram suspension.3.The effects of different dispersants and thickeners on the rheological behavior of fluopyram suspension system were studied.The rheological behavior of 550S,A700 and 4913 dispersants was a non Newtonian pseudoplastic fluid,which was in accordance with Herschel-Bulkley model.After 3 min and 10 min of steady-state pre shear,the viscosity of the suspension system of fluopyram prepared by the three dispersants showed periodic change with time,the vibration amplitude did not change much,the vibration frequency was basically the same,and the structure of the suspension system could be homogenized after 3 min of pre shear;the suspension system of 0.2%xanthan gum and 3%magnesium aluminum silicate showed shear thinning behavior,and the best fitting model of rheological data was consistent with Ostwald model and Herschel-Bulkley model.