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Bio-Based Wood Adhesives: Current Advances in Polymer Architecture and Structure–Property–Sustainability Integration
(2026-07-01)
Dangwilailux, Panya
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Rachsiriwatcharabul, Natworapol
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Lakachaiworakun, Putipong
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Eakvanich, Visit
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Wattana, Wassachol
The development of bio-based adhesives has emerged as a viable strategy to reduce fossil-derived resin consumption in wood and wood-based panel applications. This review provides a polymer-focused assessment of adhesive systems derived from proteins, carbohydrates, lignin, and tannins, emphasizing molecular architecture, crosslinking chemistry, interfacial interactions, and structure–property relationships. Adhesive performance is primarily dictated by functional group density, crosslinking efficiency, and network topology. Protein-based adhesives rely on hydrogen bonding and covalent crosslinking with lignocellulosic substrates but require structural modification to improve hydrothermal stability. Carbohydrate-based systems, including starch and cellulose derivatives, offer reactive hydroxyl functionalities that enable oxidation, esterification, and etherification pathways for enhanced network formation. Lignin and tannins, characterized by phenolic and aromatic structures, facilitate condensation reactions and enable partial substitution of phenol in thermosetting resins, supporting low-formaldehyde or formaldehyde-free formulations. Hybrid polymer networks, particularly protein–carbohydrate and lignin-modified systems, demonstrate improved crosslink density, reduced hydrophilicity, and enhanced mechanical performance. Life cycle analyses indicate that increasing biogenic carbon content and minimizing fossil-based cross-linkers can lower global warming potential (GWP) and volatile organic compound (VOC) emissions. Overall, a structure–property–sustainability framework is proposed to guide molecular design and performance optimization of next-generation bio-based wood adhesives.
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Repurposing Senescent Oil Palm Trunks into Sustainable Plywood: A Green Alternative to Conventional Disposal Practices
(2026-01-01)
Rachsiriwatcharabul, Natworapol
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Dangwilailux, Panya
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Kalasee, Wachara
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Autthanit, Chaowat
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Lakachaiworakun, Putipong
This study evaluates the mechanical performance and carbon emission implications of producing plywood from senescent oil palm trunks (OPT), a readily available agricultural residue in Thailand. Veneers were dried using hot air at 90℃ and a hybrid hot air–microwave process before being fabricated into plywood with urea–formaldehyde adhesive. Mechanical tests showed that plywood from hybrid-dried veneers (OPP-H90-M2k) achieved higher tensile strength and modulus of rupture (MOR) than hot-air drying alone (OPP-H90), while bondline shear strength remained consistently high. However, MOR and modulus of elasticity values were lower than those of commercial plywood, suggesting that OPT plywood is currently better suited for non-structural interior applications such as furniture and partitions. A simplified carbon emissions inventory indicated that OPT plywood production released about 843 kg CO<inf>2</inf>-eq/m3, compared with 990 kg CO<inf>2</inf>-eq/m3 for open burning and 800– 1,200 kg CO<inf>2</inf>-eq/m3 for natural decomposition. Although its footprint is higher than advanced low-carbon plywood systems, the results suggest that OPT plywood offers a moderate emissions reduction and provides partial carbon storage within the product. Overall, converting OPT into plywood represents a practical alternative to unsustainable disposal practices and supports more sustainable biomass utilization in tropical agriculture.
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Effects of Wood Vinegar as a Coagulant in Rubber Sheet Production: A Sustainable Alternative to Acetic Acid and Formic Acid
(2025-07-01)
Eakvanich, Visit
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Lakachaiworakun, Putipong
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Rachsiriwatcharabul, Natworapol
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Wattana, Wassachol
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Kalasee, Wachara
Occupational exposure to commercial formic and acetic acids through dermal contact and inhalation during rubber sheet processing poses significant health risks to workers. Additionally, the use of these acids contributes to environmental pollution by contaminating water sources and soil. This study investigates the potential of three types of wood vinegar—derived from para-rubber wood, bamboo, and eucalyptus—obtained through biomass pyrolysis under anaerobic conditions, as sustainable alternatives to formic and acetic acids in the production of ribbed smoked sheets (RSSs). The organic constituents of each wood vinegar were characterized using gas chromatography and subsequently mixed with fresh natural latex to produce coagulated rubber sheets. The physical and chemical properties, equilibrium moisture content, and drying kinetics of the resulting sheets were then evaluated. The results indicated that wood vinegar derived from para-rubber wood contained a higher concentration of acetic acid compared to that obtained from bamboo and eucalyptus. As a result, rubber sheets coagulated with para-rubber wood and bamboo vinegars exhibited moisture sorption isotherms comparable to those of sheets coagulated with acetic acid, best described by the modified Henderson model. In contrast, sheets coagulated with eucalyptus-derived vinegar and formic acid followed the Oswin model. In terms of physical and chemical properties, extended drying times led to improved tensile strength in all samples. No statistically significant differences in tensile strength were observed between the experimental and reference samples. The concentration of acid was found to influence Mooney viscosity, the plasticity retention index (PRI), the thermogravimetric curve, and the overall coagulation process more significantly than the acid type. The drying kinetics of all five rubber sheet samples displayed similar trends, with the drying time decreasing in response to increases in drying temperature and airflow velocity.
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Thin-Layer Drying Model and Antifungal Properties of Rubber Sheets Produced with Wood Vinegar as a Substitute for Formic and Acetic Acids
(2025-05-01)
Wattana, Wassachol
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Lakachaiworakun, Putipong
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Rachsiriwatcharabul, Natworapol
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Eakvanich, Visit
;
Dangwilailux, Panya
Currently, workers in the ribbed smoked sheet (RSS) rubber production industry face increasing health risks, primarily due to their direct involvement in converting fresh latex into raw rubber sheets. This process involves the manual addition of appropriately diluted commercial formic acid and acetic acid to induce coagulation, resulting in a tofu-like consistency, which is subsequently processed into rubber sheets. Previous studies have indicated that the use of commercial formic and acetic acids poses significant health hazards to workers and contributes to environmental pollution. Therefore, this study explores the feasibility of replacing commercial formic and acetic acids with wood vinegar derived from para-rubber wood, bamboo, and eucalyptus in the RSS production process. Wood vinegar samples from the three biomass sources were analyzed for their organic compound compositions using gas chromatography and subsequently used as coagulants in the preparation of raw rubber sheets. The drying kinetics and antifungal properties of the resulting sheets were then evaluated. The results revealed that wood vinegar derived from para-rubber wood contained the highest concentration of acetic acid (41.34%), followed by bamboo (38.19%) and eucalyptus (31.25%). Rubber sheets coagulated with wood vinegar from para-rubber wood and bamboo exhibited drying kinetics comparable to those obtained using acetic acid, with the two-term exponential model providing the best fit. Conversely, rubber sheets coagulated with eucalyptus-derived wood vinegar, which had a relatively high concentration of phenolic derivatives (22.08%), followed drying behavior consistent with the Midilli et al. model, similar to sheets treated with formic acid. In terms of antifungal properties, five fungal genera—Aspergillus, Penicillium, Fusarium, Trichoderma, and Paecilomyces—were identified on the rubber sheets. Fungal growth was most pronounced in the control samples (untreated with wood vinegar), whereas samples treated with wood vinegar exhibited significantly reduced fungal colonization. These findings indicate that wood vinegar is effective in inhibiting fungal growth on the surface of rubber sheets and may serve as a safer and more environmentally friendly alternative to commercial acid coagulants.
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Sound Absorption Properties of Natural Fiber Composite from Areca Nut Shells Fibers with Polyvinyl Alcohol
(2025-01-01)
Kalasee, Wachara
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Eakvanich, Visit
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Rachsiriwatcharabul, Natworapol
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Wattana, Wassachol
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Dangwilailux, Panya
This research investigates the development of sound-absorbing composites using areca nut shells fibers (ANS) bonded with polyvinyl alcohol glue, aiming to create an environmentally friendly and sustainable alternative to conventional synthetic materials. The research explores the effects of varying thicknesses (10, 20, and 30 mm) and fiber lengths (10, 20, and 30 mm) on the sound absorption performance of the composites. The sound absorption coefficient (SAC) was measured using the impedance tube method to determine the composites’ effectiveness across different frequency ranges. The results indicate that the thickness of the composite significantly enhances sound absorption, particularly in the low-frequency range (1,500–2,500 Hz). Composites with a fiber length of 30 mm demonstrated the most effective sound absorption properties at 0.90 above 1,600 Hz (ANS-T30-L30). Additionally, blending fibers of different lengths led to SAC changed behavior. This study contributes to the growing body of knowledge on sustainable materials by utilizing agricultural waste to produce functional and eco-friendly sound-absorbing composites.

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