Formaldehyde-free epoxidized soybean oil-based resin has been prepared under acidic conditions by co-condensation of the epoxidized soybean oil and condensed tannin originating from agricultural and forestry sources as the main raw materials, whereas 1,6-hexanediamine was employed as a cross-linking agent. Fourier transform infrared spectroscopy (FTIR) and electrospray ionization (ESI) corroborated that tannin and epoxidized soybean oil underwent crosslinking under acidic conditions supported by hexamethylenediamine. A bio-based grinding wheel was fabricated by formulation of the developed resin with wood powder as source of grinding particles. The appearance, hardness, compressive strength and wear resistance of the resulting grinding wheel were studied. The results have shown that the grinding wheel possesses a smooth surface with no bubbles or cracks, and its hardness and wear resistance were greater than that of a phenolic resin-based grinding wheel. Interestingly, the grinding wheel incorporates more than 90% of its raw materials as biomass renewable materials; thus, it is generally considered non-toxic. In addition, the future feasibility of this approach to replace some petrochemical resins that are frequently used in the fabrication of grinding wheels is considered.
Keywords: bio-based materials; epoxidized soybean oil; grinding wheel; hexanediamine; tannin.