Papers by Author: Hong Ming Lou

Abstract: Lignin-modified amino-sulfonic acid-based dispersant LMA was synthesized by using soda lignin to substitute part of phenol. Effect of LMA on ceramic slurry performance was studied and compared with inorganic salt dispersant. The addition of LMA endows ceramic slurry with lower viscosity, better fluidity and stability. Particle size of ceramic slurry blended with LMA is clearly decreased and grinding efficiency improves. LMA can enhance particle electro-negativity by complexing high valence cations and polymeric anion-adsorbing on ceramic particles surface by hydrogen bonds. The dispersive effect of LMA to ceramic particles is the combined action of steric effect and electrostatic repulsion.

Abstract: Calcium lignosulfonate (CL) was separated into three fractions with different molecular weight by using ultrafiltration membranes, and the effect of the composition of commercial CL on the setting time of Portland cement with anhydrite was studied in this paper. Results show that the CL fraction with the cut-off molecular weight of less than 150 (CL-A) shortens setting time most. Further analysis indicates that the content of reducing sugar in CL-A reaches to 15.3%, including mannose, glucose, galactose, xylose and arabinose, and these five kinds of monosaccharides are found to be the main components of inducing quick set of cement. Ultrafiltration is an effective method to remove most of the reducing sugar in CL and weaken the quick set of Portland cement with anhydrite.

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: Lignosulfonate (LS) is an important dispersant for wettable powder (WP). Though domestic products of lignosulfonate in China are very cheap compared to imported products, their performance is often inferior. Two modified products GCL4-1 and GCL4-A, from sodium lignosulfonate and alkali lignin respectively, were developed and their dispersive effects on the performance of 40% myclobutanil wettable powder (WP) were studied compared with the imported product Borresperse Na and the domestic product SXMN. Results show that GCL4-1 and GCL4-A have superior performance in these properties: suspensibility, wettability, surface tension, contact angle and solution retention. GCL4-A was found to be a suitable dispersant for the wettable powder pesticide for it has the best performance per unit price.

Abstract: Modified sulfanilate-phenol-formaldehyde condensate (MSPF) was synthesized by a reaction among soda lignin, sodium sulfanilate, phenol and formaldehyde. Optimal conditions of synthesis were obtained by studying the effects of raw material consumptions and reaction time on the dispersive property of products. Evaluation the applying performance of MSPF indicated that this new superplasticizer has an excellent water-reducing effect, and it can improve the compressive strength of hardened concrete obviously, especially the latter compressive strength. Most important of all, MSPF not only inherits the slump-maintaining capacity of aminosulfonate-based superplasticizer, but also overcomes the shortcoming of bleeding by improving the water retention capacity and reduces the segregation of mortar or concrete. Results show that MSPF is a potential superplasticizer for the high-strength and high-performance concrete.