Application of citric acid as natural adhesive for wood

Abstract

The development of natural adhesives derived from nonfossil resources is very important for the future. Besides, it is desirable to be safe adhesives without using harmful chemical substances. In this study, application of citric acid as a natural adhesive was investigated. Citric acid powder and bark powder obtained from Acacia mangium were used as raw materials. Citric acid powder was mixed with the bark powder, and the resulting powder mixture was poured into a metal mold. The mold was hotpressed at 180 C and 4 MPa for 10 min, and a bark molding was then obtained. The specific modulus of rupture and modulus of elasticity values of the molding containing 20 wt % citric acid were 18.1 MPa and 4.9 GPa, respectively. The molding did not decompose during a repeated boiling treatment. To clarify the effect of tannin on the adhesiveness of molding, bark was separated into tannin and residue. The molding was not obtained while using the tannin due to the marked fluidity, whereas it was obtained while using the residue, the same as while using the bark. It was considered that components other than tannin contributed to the adhesiveness. Based on the results of Fourier transform infrared spectra, the formation of ester linkages between carboxyl groups derived from citric acid and hydroxyl groups in the bark was confirmed. Accordingly, citric acid brought an adhesion by chemical bonding, and it could be used as a safe natural adhesive.

Bonding Ability of a New Adhesive Composed of Citric Acid-Sucrose for Particleboard

“…A similar trend was found for bamboo particleboard bonded using citric acid at concentrations ranging from 10% to 40% (Widyorini et al 2014). The carbonyl group was present because of the reaction of the hydroxyl groups from the lignocellulosic materials and carboxyl groups from citric acid (Umemura et al 2011). Compared to citric acid, Fig.…”

“…In contrast to fossil fuels, the use of renewable resources (such as biomass) for adhesives provides a remarkable number of environmental advantages. Many studies have focused on finding new adhesives based on renewable materials, such as citric acid (Umemura et al 2011;Widyorini et al 2016), modified lignin (Nasir et al 2013), citric acid with sucrose (Umemura et al 2013(Umemura et al , 2015, tannin with sucrose (Zhao and Umemura 2014), and glucose with sucrose (Tondi et al 2012;Lamaming et al 2013). Citric acid, which is a natural organic polycarboxylic acid containing three carboxyl groups, could act as a binding agent for boards made from wood and bark (Umemura et al 2011;Umemura et al 2012), various bamboo species (Widyorini et al 2016), and oil palm frond (Widyorini et al 2012).…”

Influence of Urea-formaldehyde Adhesive Modification with Beech Bark on Chosen Properties of Plywood

“…It was also shown that amounts of bark higher than 12.25% significantly worsened the mechanical strength, formaldehyde release, and the thickness swelling. Another study (Umemura et al 2012) showed that the physical and mechanical properties required for furniture manufacturing could be achieved with 30% bark content.…”

Sifat Fisika Mekanika dan Ketahanan Papan Partikel Bambu dengan Perekat Asam Sitrat terhadap Serangan Rayap Kayu Kering

“…Salah satu bahan pengaktif alami yang mulai dikembangkan adalah asam sitrat (2-hydroxy-1,2,3-propanetricarboxylic acid) yang mengandung tiga gugus karboksil dan terbukti dapat digunakan sebagai agen pengikat pada produk moulding dari kulit dan kayu akasia (Umemura et al, 2011 (Umemura et al 2011;2012 Gugus C=O ini juga dihasilkan oleh degradasi dari hemiselulosa selama proses pengempaan panas (Widyorini et al, 2005). Perbedaan intensitas gugus C=O pada dua suhu pengempaan pada penelitian ini tidak terlihat jelas pada spektrum FTIR.…”