Molecules (Aug 2024)

Controlling and Tuning the Dispersion Properties of Calcined Kaolinite Particles in Various Organic Solvents via the Modification Method Using Triethoxyvinylsilane and 3-Mercaptopropionic Acid

  • Yongbing Yuan,
  • Xinyu Tang,
  • Junkang Shi,
  • Congshan Zhou,
  • Lijun Li,
  • Honghong Sun,
  • Derek O. Northwood,
  • Kristian E. Waters,
  • Hao Ma

DOI
https://doi.org/10.3390/molecules29174129
Journal volume & issue
Vol. 29, no. 17
p. 4129

Abstract

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The surface of calcined kaolinite particles underwent chemical modification using Vinyltriethoxysilane (VTMS) and 3-mercaptopropionic acid (3-MPA). The grafting ratio of VTMS on the calcined kaolinite surface was adjusted by varying its quantity. FT-IR analysis revealed the initial grafting of VTMS onto the kaolinite surface, resulting in the formation of a C=C reactive site on the surface. Subsequently, an olefin click reaction with 3-MPA occurred, leading to the effective grafting of 3-MPA onto the kaolinite surface and the formation of an efficient coating. Thermal analysis indicated that the optimal grafting level was achieved at a modifier content V:K ratio of 0.5. The estimated grafting ratio of the modifier on the kaolinite surface was approximately 40% when V:K was 0.5. Water contact angle and dispersion experiments demonstrated that the surface properties of kaolinite were effectively controlled by this modification approach. At V:K = 0.3, the modified kaolinite particles exhibited good dispersion in both polar and non-polar solvents. In polar solvents, the average particle size of modified kaolinite was below 1100 nm, while in non-polar solvents, it did not exceed 5000 nm. Considering all aspects, a V:K ratio of 0.3 is recommended. Further investigation into the impact of adding 3-MPA on the surface properties of modified kaolinite particles based on V:K = 0.3 revealed that the hydrophilicity of the modified particles could be enhanced. However, it is advised to keep the maximum M:V ratio (3-MPA to kaolinite) at 1.0.

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