Papers by Author: Ming Song Zhou

Abstract: The dispersive effect of four lignosulfonates (Kinsperse126, sodium lignosulfonate, magnesium lignosulfonate and a modified lignosulfonate GCL4-1) on the stability of Dimethomorph (DMM) water based suspension with different particle sizes was investigated. DMM suspension without dispersant was unstable owing to the strong aggregation of particles, while the stability was increased after the addition of lignosulfonate (LS), which can be adsorbed on the particle surface and weaken the aggregation of particles. Moreover, the higher sulfonated degree of LS, the better the dispersible ability was. Compared with LS of high sulfonated degree which could improve the zeta potential of DMM, LS with high molecular weight had larger adsorption capacity and steric effect on the pesticide particles. Associated with the dispersive behavior of DMM suspension, the electrostatic repulsion was found to be the more important factor impacting the stability of DMM suspension by comparison with the steric effect.

Abstract: Water-soluble carboxymethylated lignin (CML) was synthesized using wheat straw alkali lignin (WAL) in aqueous medium. The process of carboxymethylation was optimized with respect to the NaOH concentration, monochloroacetic acid concentration, reaction temperature and time. The optimized product has a yield of 80.47% and a carboxyl group content of 2.8231 mmol•g-1, respectively. The optimum conditions for carboxymethylation are NaOH concentration of 20.0% (wt%), monochloroacetic acid concentration of 37.5% (wt%), temperature of 70 °C and time of 90 min. The optimized CML was characterized by FTIR spectroscopy, 1H NMR spectroscopy and interfacial tension apparatus. The result shows that the substitution reaction of carboxymethylation occurs simultaneously in the phenolic hydroxyl group and aliphatic hydroxyl group in WAL. CML has the surface activity in water for industrial application as dispersant.