Low formaldehyde emission particleboard bonded with modified crosslinked carboxymethyl starch as bio-adhesive

Abstract

The potential and suitability of natural based adhesives synthesized from oil palm trunk (OPT) starch for wood-based composites were evaluated for its chemical and physical properties. In this study, the OPT starch was chemically modified with sodium chloroacetate (C₂H₂CINaO2) and phosphoryl chloride (POCI3) to produce modified crosslinked carboxymethyl starch (CMS) as bio-adhesives. The chemical modification not only altered the physical appearance of OPT starch but also the chemical content in the modified starch. For pot life test, the CMS showed a shorter time required for the starch paste to harden compared to native OPT starch (NS). For solid content, the CMS showed a higher percentage compared to NS with 32.54% and 27.49%, respectively. For starch content, protein, lipid, ash and amylose content, the NS gave higher reading compared to the CMS. However, the amylopectin content that represented the branched structure in starch increased after the modification. For formaldehyde release test, as expected, the wood-based particleboard bonded with CMS mixed with 2% urea formaldehyde (UF) resin showed lower percentage of formaldehyde release compared to the control samples that were made by using 15% of UF resin.