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The sustainability, performance, and cost of production in the plywood industry depend on wood adhesives and the hot-pressing process. In this study, a cold-setting plywood adhesive was developed based on polyvinyl alcohol (PVOH), high-purity lignin, and hexamine. The influence of lignin content (10%, 15%, and 20%) and cold-pressing time (3, 6, 12, and 24 h) on cohesion, adhesion, and formaldehyde emission of plywood were investigated through physical, chemical, thermal, and mechanical analyses. The increased lignin addition level lowered the solids content, which resulted in reduced average viscosity of the adhesive. As a result, the cohesion strength of the adhesive formulation with 10% lignin addition was greater than those of 15% and 20% lignin content. Markedly, the adhesive formulation containing a 15% lignin addition level exhibited superior thermo-mechanical properties than the blends with 10% and 20% lignin content. This study showed that 10% and 15% lignin content in the adhesive resulted in better cohesion strength than that with 20% lignin content. However, statistical analysis revealed that the addition of 20% lignin in the adhesive and using a cold-pressing time of 24 h could produce plywood that was comparable to the control polyurethane resins, i.e., dry tensile shear strength (TSS) value of 0.95 MPa, modulus of rupture (MOR) ranging from 35.8 MPa, modulus of elasticity (MOE) values varying from 3980 MPa, and close-to-zero formaldehyde emission (FE) of 0.1 mg/L, which meets the strictest emission standards. This study demonstrated the feasibility of fabricating eco-friendly plywood bonded with PVOH–lignin–hexamine-based adhesive using cold pressing as an alternative to conventional plywood.

The interest of using natural binder in particleboard production is still the primary concern of many researchers. The use of citric acid as an adhesive has been investigated and show satisfying results, especially in particleboard physical properties. However, the particleboard had low bending strength due to high content of citric acid on the particleboard affected the brittleness of the particles. Therefore, the application of citric acid in particleboard production usually combined with other natural adhesives. In this study, a combination of citric acid (CA) and maltodextrin (MD) was used in the production of sorghum bagasse particleboard with a ratio of 1:1. The particleboard was produced with a target density of 0.8 g/cm3, using 15%, 20%, 25% and 30% CA-MD content, hot-pressed at 200°C and 5 MPa for 8 or 10 minutes. The mixture of citric acid and maltodextrin (1:1) was successfully acting as bonding agent in sorghum bagasse particleboard production, mainly when used at 30% adhesive content. The particleboard modulus of rupture and modulus of elasticity, fulfilled the standard of type 8 particleboard, according to JIS 5908. The particleboard physical properties were excellent, proved by the value of particleboard thickness swelling, which was under 12%. This is due to the superb bonding from the combination of citric acid and maltodextrin, as shown by the internal bond values, which exceeded 0.3 N/mm2, the minimum requirement for type 18 particleboards based on JIS A 5908.

The objective of this research was to determine the wood basic properties of eight years-old fast-growing teakwood (Tectona grandis – Platinum teak wood), in the radial direction of the stem. The anatomical features of the examined teak wood showed semi-ring porous and in general, they had a similarity to those of the conventional teak wood. The ray cell proportion was increased along with the increased distance from the pith area. The size of vessel cell tended to change from pith to the outer part. The radial (R) and tangential (T) shrinkage had improvement compared to those of five years-old Platinum teak wood. The R and T shrinkages were 2.89% and 6.2%, respectively. The present results suggested that wood properties of eight years-old Platinum teak wood is more stable than those of five years-old as reported in the previous study. The compression strength was also increased during the increase of growth age. The values of compression perpendicular and parallel to the grain were 76.74 kg/cm2 and 367.9 kg/cm2, respectively. The increasing of the radial properties indicated that eight years-old Platinum teak wood was still in juvenile stage.

Sonokeling (Dalbergia latifolia Roxb) stands are widely lost throughout the world. Sonokeling is currently classified as an Appendix II CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) wood. Therefore, a study on the existence and characteristics of Sonokeling were expected to contribute in providing population data and basic properties of the wood. Exploration was conducted in Plot No. 25, KPH (Forest Management Unit) Gundih, Perum Perhutani Cepu, Central Java. Sonokeling stands have been planted since 1975 (more than 40 years-old) in an area of 54.20 ha, which was not productive for Teak and mixed with Mahogany. Sample was taken from upper part of stem with around 30 cm in diameter and 30 cm in length. The sample was further cutted into 2 x 2 x 2 cm for physical, 30 x 2 x 2 cm for Modulus of Elasticity (MOE) and Modulus of Rupture (MOR), and 4 x 2 x 2 cm for Compression Strength Parallel to the Grain (CSPG) tests. The results showed that specific gravity of sapwood dan heartwood were 0.79 and 0.82, respectively. The average values of MOE, MOR, and CSPG were 117,722, 1122.19, and 1022.93 kgf/cm2, respectively. Therefore, Sonokeling can be classified into Strength Class II.

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Indonesia as a tropical country has a various source of renewable resources; rattan is one of them. Rattan (Calamus rotang L.) is mainly utilized as raw material for furniture. Several wastes such as core and bark are produced during the process of furniture making. This research was conducted to investigate the properties of particleboard made from core and rattan bark. Rattan particle with moisture content less than 5% was mixed with the adhesive. Phenol formaldehyde (PF) 12% was used as the adhesive. The mixed particle was then hot pressed for 10 minutes at 150 °C with 25 kgf/cm2. Board dimension was 25 x 25 x 1 cm. Before testing, boards were conditioned for seven days. Testing was conducted for physical and mechanical properties according to JIS A 5908-2003. Surface roughness testing, as well as wettability, was also conducted to investigate the surface properties of particleboard.

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