Greener tannin–resorcinol–formaldehyde adhesive derived from Acacia mangium for the manufacture of multiply bamboo panel products

Considering the toxicity and carcinogenicity of formaldehyde, there is a strong need to reduce the use of formaldehyde in the adhesive system. This study uses tannin–resorcinol–formaldehyde (TRF) as an alternative bio-based adhesive to produce multiply bamboo panels from Tali bamboo (Gigantochloa apus). TRF adhesive has been prepared using tannin extracted from mangium bark (Acacia mangium), as one of the high tannin content sources, together with resorcinol and formaldehyde. The addition of tannin in TRF adhesive formulation in this study has reduced the amount of formaldehyde by 33% compared to PRF as the conventional adhesive. In addition, TRF adhesive was improved with wheat flour as the extender, to increase the physical properties and reduce the cost of adhesive, as well as to improve the mechanical properties of multiply bamboo panel. This study investigated the effect of ply composition and extender concentration on the physical and mechanical properties of multiply bamboo panels. The results showed that ply composition and extender concentration significantly affected the physical and mechanical properties of multiply bamboo panels. Based on these results, 21 of the 25 types of multiply bamboo panels produced had properties that met Japanese Agricultural Standards (JAS) and Indonesian National Standard (SNI) (except modulus of elasticity). This study demonstrated that the TRF adhesive prepared from mangium tannin containing wheat flour as the extender could be used as an alternative adhesive in the multiply bamboo panel industry with further development to have all the properties that meet the standards.