Dianion Synthesis And Application Of Dispersants

We synthesized polymer dispersant, then determined its performance and studied its application in WDG.The dispersants were synthesized via copolymerization of acrylic acid (AA), styrene sulfonic sodium (SSS) and 3-hydroxypropyl acrylate (HPA) in aqueous solution through orthogonal experiments. It was studied that the influence factors on the dispersing characteristics of these copolymers, which involved molar ratio of the monomers, initiator concentration and reaction temperature. The molecular weight, HLB, CMC were determined respectively. The best dispersants were chosen out based on the excellent dispersibilities for the inorganic granules(BaSO4 ,TiO2) or the organic granules(atrazine, imidacloprid, fipronil, diuron).The effects of temperature, pH, ionic strength and dispersant concentration on the suspension rate of BaSO4 granules were studied with the best dispersant. Sedimentation speed of BaSO4 particles was determined as well as the dispersant adsorption. The suspension percentage of the granules increased as temperature increased from 5℃to 20℃, or pH fom 2 to 10 while decreased as temperature further increased from 20℃to 55℃,or pH increased from 10 to 12.5. The suspension percentage initially decreased after addition of NaCl and reached its minimum when the NaCl concentration was 0.1M. The adsorption increased with increasing copolymer concentration in a Langmuirian mode and reached a plateau at the concentration of 4 g/L. Size distribution of the particles was analyzed. The average particle size in the presence of the dispersant was less than that in the absence of the dispersant. Using synthesized dispersant, well-dispersed suspension of BaSO4 could be achieved. The suspension rate of BaSO4 granules was 99.18% with 0.4 g dispersant at pH 7 and 20℃. At the same condition, the average diameter of BaSO4 particles was about 350 nm and the clear liquid volume above was only 2% after 60h standing.The sedimentation speed of TiO2 particles was determined with the best dispersant as well as the dispersant adsorption. The adsorption increased with increasing copolymer concentration in a Langmuirian mode and reached a plateau at the concentration of 4.2 g/L. Size distribution of the particles was analyzed. The average particle size in the presence of the polymer was less than that in the absence of the polymer. Using synthesized dispersant, well-dispersed suspension of TiO2 could be achieved. The suspension rate of TiO2 granules was 90.14% with 0.06 g dispersant when pH and temperature were 7 and 20℃respectively. At the same condition, the average diameter of TiO2 particles was about 3500 nm and the clear liquid volume above was about 15.5% after 60h standing. The suspension rate of TiO2 granules was 99.15% with 0.4 g dispersant when pH and temperature were 7 and 20℃respectively. At the same condition, the average diameter of TiO2 particles was about 220 nm and the clear liquid volume above was only 2% after 60h standing.The concentrations of WDGS for atrazine, Imidacloprid, fipronil, diuron which were prepared with the best dispersants were 90%,80%,80%,90% respectively. A practical and rapid method for screening the formulation of WG (water dispersible granule) was introduced. In the method,the triangle coordinate based on the content of the three variables was built,and the important and simple metewand as the guide line was selected. The experimental results showed that the optimized copolymers had excellent efficiencies, which were close to that of Rhodia T36 and TERSPERSE 2700.