Adsorption of anionic polyelectrolyte on an SiC surface and effects on dispersion stability. Issue 9 (9th May 2022)

• Record Type: Journal Article
• Authors: Zhang, Wenxiao; Zhang, Yue; Niu, Yifan; Liu, Jiaxiang
• Is Part Of: Journal of the American Ceramic Society. Volume 105:Issue 9(2022)
• Page Start: 5611
• Page End: 5626
• Publication Date: 2022-05-09
• Subjects: adsorption -- anionic polyelectrolyte -- powder dispersion -- SiC powder; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.18528
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: Aluminum nitrate (Al(NO3 )3 ) and sodium polystyrene sulfonate (PSS) were used to improve the dispersion of fine silicon carbide (SiC) powders. Effects of modification parameters on the viscosity of modified SiC slurry were studied by orthogonal experiments. Modified SiC slurry with the solid loading of 50 vol% reached the lowest viscosity of 34 MPa s. The adsorption processes of PSS on the as‐received and Al(NO3 )3 premodified SiC surface were investigated. The results indicated that the adsorption between PSS and premodified SiC surfaces was a high affinity type and was mainly controlled by active sites on an SiC surface. The Langmuir model and the pseudo‐second‐order model could better fit the adsorption isotherm and kinetics data, respectively. The contact angle decreased from 32.8 to 15.2° and the wettability was improved by modification. The isoelectric point of modified SiC powder shifted to the acidic region and the maximum zeta potential was obtained at pH 11. Sedimentation results also showed that a stable dispersed suspension of modified SiC was achieved at pH 11. Density–pressure curves demonstrated that the flowability and formability of SiC powder were improved by modification. The dispersion effect of PSS on SiC and Al2 O3 composite powder was verified by viscosity and sedimentation results. Abstract : Graphical Abstract: Modified SiC powders with great dispersion were prepared by a novel binary modifier combination of Al(NO3 )3 and PSS. Negatively charged PSS chains were absorbed on an Al(NO3 )3 ‐modified SiC surface by the electrostatic attraction between functional groups of PSS and active sites on SiC surface.