Papers by Author: Yong Hong Deng

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: Alkali lignin (AL) was used as a polyanion to form layer-by-layer self-assembled film with PDAC as a polycation. The effects of temperature and concentration on the adsorption characteristics of AL were investigated. Iodine was added into AL solutions to study the role of π-π interaction in self-assembly of AL and PDAC. Results show that the self-assembly of AL/PDAC is mainly driven by π-π interaction and electrostatic interaction. A higher temperature or a larger concentration can enhance the aggregation of lignin. I₂ can form lignin–iodine charge–transfer complexes with AL to reduce the degree of aggregation of AL, so the adsorbed amount of AL decreases significantly with increasing iodine contents.

Abstract: To solve the solubility problem of conductive poly (3,4-ethylenedioxy thiophene) (PEDOT), PEDOT was synthesized from polymerization of 3,4-ethylenedioxy thiophene (EDOT) in aqueous lignosulfonate (LS) solutions with ammonium persulfate as the oxidant. Results showed that conductive polymer PEDOT was successfully obtained in the present of LS, and the PEDOT/LS conductive compounds could be well dispersed into water. The effective diameter of the PEDOT/LS compounds decreased with increasing feed ratio of EDOT:LS. When the EDOT:LS ratio was up to 3.5:1, the effective diameter of PEDOT/LS was about 100 nm as detected by light scattering and TEM. The surface resistance of PEDOT/LS coating was about 107 Ω/sq, and had little change after treatment of washing and heating, so the PEDOT/LS dispersion could be used as a good antistatic agent.

Abstract: The temperature dependence of the dynamics of sodium lignosulfonate (NaLS) solution with high salt concentration was investigated by static and dynamic light scattering. The results showed that there existed fast mode and slow mode in NaLS aqueous solution. After enough addition of salt (1.2 M NaCl), slow mode in NaLS solution disappeared when NaLS molecules became electric neutrally. On this basis, the NaLS molecules aggregated and leaded to the re-formation of slow mode if the temperature of NaLS solution was above 311.15K. There was no splitting phenomenon in correlation function and size distribution when slow mode appeared under room temperature in NaLS solution. The correlation function would split into two stages when the size difference between fast and slow modes exceeded certain limit.