Manufacture and properties of citric acid-bonded particleboard made from bamboo materials

Utilization of citric acid as natural binder for non-wood composite is still limited. Therefore, this study investigated the physical and mechanical properties of particleboard made from bamboo using citric acid as natural binder. Three bamboo particles, i.e. petung bamboo (Dendrocalamus asper), wulung bamboo (Gigantochloa atroviolacea), and apus bamboo (Gigantochloa apus) were used as raw materials in this research. Citric acid contents were set at 0, 15 and 30 wt.% based on air-dried particles. Two classifications of petung bamboo particle sizes (coarse and fine particles) were used in this research. The particleboards were also made as single layer and three layer boards with variation of layer compositions. The results showed that addition of citric acid could significantly improve the dimensional stability and mechanical properties of the boards, while bamboo species did not significantly affect the properties of boards. Fine particles provided higher internal bond strength of the particleboard than coarse particles, due to bigger contact area among fine particles. Single layer particleboard provided higher internal bond strength compared to the three layer ones. The properties of citric acid-bonded bamboo particleboard in this research could meet the requirements of the Japanese Industrial Standard for particleboard (A 5908). Fourier transform infrared analysis indicated that the peak at around 1734 cm⁻¹ was hardly recognized in binderless board, however it clearly appeared in citric acid-bonded particleboards. As a result of reaction between citric acid and bamboo, good properties of particleboards could be obtained.