Evaluation of sustainable composites of sugarcane bagasse and combined algae-soy protein binders

The development of sustainably-sourced adhesives is essential to displace conventional particleboard adhesives made from formaldehyde and other petroleum derivatives. This work evaluates the mechanical properties of particleboards prepared from sugarcane bagasse, spirulina algae powder, soy flour, and sodium hydroxide at various algae to soy ratios and denaturation times. The rheology of the adhesive was characterized using the Hershel-Bulkley method to determine the yield stress (max. 288 Pa) and flow behavior index (0.21–0.54). The lap shear strength (max. 3.02 N/mm2) was also determined. For the particleboard, the secant modulus of elasticity (max. 1.12 GPa), tangent modulus of elasticity (max. 1.30 GPa), modulus of rupture (max. 11.62 N/mm2), and internal bond strength (max. 0.09 N/mm2) were determined. These particleboards met the minimum requirement set by ANSI/A208.1–1999 for general-use particleboards for the modulus of elasticity and modulus of rupture, but they did not meet the standard for internal bond strength. [Display omitted] •Introduces sustainable composites from sugarcane bagasse, algae, and soy proteins.•Considers mixtures of algae and soy to reduce food competition from protein glues.•Characterizes rheology and lap shear strength of the glues.•Evaluates flexural properties and internal bond of the resultant composites.•Flexural properties met ANSI standards, but internal bond strength did not.