Effect of citric acid content and extractives treatment on the manufacturing process and properties of citric acid-bonded Salacca frond particleboard

This study focused on the effect of an extractive treatment and the application of citric acid on the properties of particleboard made from Salacca frond. In general, extractives have a negative effect on the bondability of synthetic resin. However, the effect of extractives on the bonding mechanism of citric acid as the biobased adhesive is unclear. Unextracted and extracted Salacca frond were used as the raw materials. A hot water extractive treatment was conducted by boiling the particles for 2 h. The boards were manufactured under the following conditions: citric acid content of 0; 10; 20 weight percent (wt), pressing temperature of 180 °C, and pressing time of 10 min. The target density was set at 0.8 g cm^-3. The results showed that the addition of citric acid resulted in an increase in the physical and mechanical properties of the particleboard. Interestingly, when a 20 citric acid content was applied, there were no siginificant differences in the physical or mechanical properties of the particleboards made from unextracted and extracted particles. Based on these results, it was concluded that when citric acid is used as adhesive, the hot-water extractive treatment of Salacca frond is not needed.