Sustainable panels based on starch bioadhesives: An insight into structural and tribological performance

This work was focused on evaluating the effects of polycarboxylic acid addition and retrogradation phenomenon on tribological performance, thermal, and mechanical properties of both, bioadhesives and sustainable panels. The rheological behavior of adhesives was affected by retrogradation, exhibiting formulations containing CA higher elastic modulus than those with BTCA, regardless of the acid concentration. With regard to tribomechanical properties, panels formulated with CA20 and BTCA80 adhesives presented the lower friction coefficient and wear degree. Thermocompression process induced a crosslinking reaction between wood fibers and starch-based adhesives, leading to more hydrophobic and thermally stable matrices in the presence of BTCA. The selection of the adhesive formulation depends on the moment of its use, since retrogradation limits its performance and that of the derived sustainable panels, being the adhesive CA20 more appropriate in freshly prepared formulations. Meanwhile, when the storage of the adhesive prepared in batch is required, the BTCA80 formulation would be more suitable. Thus, bioinspired materials can provide a valuable insight towards incorporating starch-based adhesives for wood applications.