No abstract

Citric acid is a potential binding agent for composite products that has three carboxyl groups that can be ester linked with the hydroxyl groups found in wood. The addition of sucrose provides hydroxyl groups and increases the amount of ester groups. This research investigated the bonding ability of a new adhesive composed of citric acid-sucrose for teak particleboard. Citric acid and sucrose were dissolved in water under various ratios, and the concentration of the solution was adjusted to 59 to 60 wt%.This adhesive solution was sprayed onto the particles at 10% resin content based on the weight of air-dried particles. Each mixture was then hot pressed at 180 and 200 °C for 10 min. The physical and mechanical properties of the particleboards were tested, and the results showed that increasing the pressing temperature affected the dimensional stability. However, increasing of citric acid in adhesive composition improved the dimensional stability and mechanical properties of the particleboards. The optimum properties of the board were achieved at a pressing temperature of 200 °C and addition of only 10% citric acid. The results also indicated that the peak intensity of C=O group increased with the addition of citric acid and increasing pressing temperature, indicating that ester linkage occurred. However, the addition of sucrose did not greatly affect the peak intensity of C=O group.

This research focused on physical and mechanical properties of biocomposite made from bamboo and citric acid as natural binder. Bamboo particles was mixed with citric acid at 0 – 40 wt% resin content based on air-dried particles and each mixture was hot pressed at 180 °C for 10 min. The result showed that addition of citric acid could improve significantly the physical and mechanical properties of particleboard. The thickness swelling was 50 % for bamboo binderless particleboard (0 wt%), whereas it decreased to 7 % under a resin content of 10 wt%. The optimum resin content in this study was 30 wt%, while the modulus of rupture dan the modulus of elasticity were 14 MPa and 4.5 GPa, respectively. The ester linkages were detected by Fourier transform infrared spectroscopy, indicating that carboxyl groups from citric acid reacted with hydroxyl groups from bamboo to produce better properties of particleboard, especially its dimensional stability. Based on these results, it was concluded that citric acid could be as a potential natural binder for bamboo particleboard.

Gelam (Melaleuca sp.) is a tidal swamp species that grows abundantly in South and Central Kalimantan swamp forest. Gelam is one potential species for wooden vinegar production as the technology is available and readily implemented. This paper studies the possible utilization of gelam wood species for wood vinegar. The vinegar was condensed during wood pyrolisis processes at the temperature of 500°C for 3 hours. Wood vinegar was yellow reddish in colour, transparant and no floating material. The vinegar specific gravity was 1.008 to 1.058 with the pH of 3.105 to 3.195 and acidity level varies from 5.167 to 12.903%. The carbonyl and phenol content were 11.250 to 30.390% and 2.429 to 9.231% respectively. In general, gelam wood can produce wood vinegar and its quality meet the Japanese standard requirements.

ABSTRACT

No abstract

No abstract

Wood waste materials such as flakes, particles, sawdust, planer shaving, which are residues from furniture industry can be utilized to manufacture many composites such as particleboard. The most commonly used particleboard has three layers: two face layers and one core layer. The face layers consist of fine particles and the core layer is made of coarse particles.This study aimed to show the effect of shelling ratio and particle characteristic on physical properties of three-layer particleboard with high density core and different particles on surface layers. The materials used in this study were hinoki (Chamaecyparis obtusa) strand and knife-milled Douglas-fir (Pseudotsuga manziesii) as surface layers and hammer-milled matoa (Pometia sp.) as core layer. The wood particles were collected from a wood company. Adhesive used was MDI resin (methylene diphenyl diisocyanate) with 6 % content in mat preparation. The pressing conditions were: temperature 180°C, pressure  3 MPa and pressing time  5 min. The target density was 0.72 g/cm3 with board size of 340 mm x 320 mm  x 10 mm. Factors used in this study were layer structure according to board shelling ratio and particle characteristic. The parameters of this study were density, moisture content, thickness swelling, water absorption, linear expansion and vertical density profile.The results of this study indicate that all boards meet the requirements of JIS A 5908-2003. Higher shelling ratio of surface layers resulted in higher physical performance of three-layer particleboard. In terms of particle type, hinoki strands showed the best performance in board density and linear expansion, while Douglas-fir particle showed the best performance in moisture content, thickness swelling and water absorption. Improvement of physical properties of particleboard with high density wood particles in core layer can be conducted by adding surface layer with higher quality wood particles such as hinoki strands or Douglas-fir particles. Compared to Douglas-fir particles, hinoki strands as surface layers contribute to higher enhancement of three-layer particleboard with matoa as the core layer.