Toward Novel Biocomposites from Unavoidable Food Supply Chain Wastes and Zirconia

Abstract

The synthesis and characterization of novel biocomposites, herein termed bioboards, derived from agricultural residues (wheat straw and barley straw) and aqueous biosilicate solutions, as binder, are reported. The addition of a small amount of protein significantly enhances board strength. The internal bond strength (IBS) increases from 0.0498 to 0.0688 N mm–2. Prior to adhesion, the agricultural residues were dewaxed (ethanol), making them more amenable to aqueous wetting. The aqueous biosilicate binder was obtained via KOH-assisted hydrothermal leaching of spent ashes derived from the combustion of wheat straw. The concentration of biosilicate was determined by ATR-IR spectroscopy and compared with commercial silicate solution (K120). Zirconia powders were introduced to increase the fireproof ability of bioboards. The presence of zirconia was evidenced by powder X-ray diffraction studies. Thus, the bioboards reported represent “greener” alternatives to conventional, commercial particle and medium density fiber boards because they are wood-free, use waste as a renewable resource (agricultural straws), and, importantly do not use any harmful phenol-formaldehyde and isocyanate binders.