School of Agriculture, Food and Ecosystem Sciences - Research Publications

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    Effects of mat composition and pressing time on citric acid-bonded ultra-low-density hemp hurd particleboard
    Fehrmann, J ; Belleville, B ; Ozarska, B ; Ismayati, M ; Dwianto, W (Elsevier, 2024-04-01)
    This study investigated the feasibility of using citric acid (CA) as a biobased and formaldehyde-free binder for producing ultra-low-density (320 to 338 kg/m3) hemp hurd particleboard (ULHPB). Mechanically decorticated hemp hurd chips were milled and then separated into fine (F), medium (M), and coarse (C) particle sizes. Three particle size mixes (PSM) were used to fabricate the panels: 100% C, 100% M, and a 50/50% mixture of CM. Each PSM was combined with low and high CA contents (20 and 30 wt%) and subjected to short and long pressing times (8 and 12 min) at 200 °C. Physico-mechanical characteristics were evaluated following Australian standard AS/NZS 1859.1 (2017) for reconstituted wood-based panels. Thermo-chemical analyses were performed to understand the properties of the raw hurd and to investigate the binding mechanisms in CA-ULHPB. The PSM had a significant impact on panel expansion (springback), internal bond strength (IB), water absorption (WA), and thickness swelling (TS) in most CA-ULHPB variants. PSM-C panels exhibited superior IB when pressed with 30 wt% CA for 12 min. The effect of PSMs diminished for WA and TS but CA content and pressing time remained highly significant. Py-GC/MS, FTIR spectroscopy and TGA indicated the formation of ester linkages with carbohydrate-derived OH-groups and the involvement of lignin moieties in the CA-ULHPB. This research identified optimal panel compositions and processing parameters for fabricating environmentally friendly composite panels using CA as a natural adhesive and hemp hurd as an agricultural by-product. The panels exhibited excellent properties and would be well suited as core layers in lightweight sandwich composites given their ultra-low-density range.
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    Gluing characteristics of Papua New Guinea timber species for various non-structural applications
    Belleville, B ; Lancelot, K ; Galore, E ; Fehrmann, J ; Ozarska, B (Universidad del Bío-Bío, 2023)
    Papua New Guinea (PNG) has abundant natural forest resources but there are many constraints which need to be addressed to support the development of competitive value-added wood industries. There is a need to develop knowledge and capacity in wood science and processing technologies which support successful domestic value-adding wood processing enterprises. A comprehensive testing program has been developed to assess the glue‐bond strength and performance of selected commercial PNG timber species in various climatic conditions to simulate service conditions in potential market destinations. Two criteria namely shear strength and wood failure have been used to determine if a species can meet the minimum requirements for either dry use or wet use applications. The performance of 24 different PNG commercial timber species has been assessed using a one-component cross-linking polyvinyl acetate emulsion adhesive. The bondability of the selected species has been carefully estimated considering the wood density and wood moisture content for the strength and durability in dry- and wet-use conditions. The testing results show that as the wood density as a wood property factor and moisture content as a service condition factor increase, high shear strength with high wood failure become more difficult to achieve consistently. The highest shear strength and wood failure results were achieved by softwood plantation species and low-density hardwood species. Based on the testing results, the selected species have been classified into bondability classes (bond very well, bond well, bond with difficulty, very difficult to bond).
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    Influence of particle granulometry and panel composition on the physico-mechanical properties of ultra-low-density hemp hurd particleboard
    Fehrmann, J ; Belleville, B ; Ozarska, B ; Gutowski, WVS ; Wilson, D (Wiley, 2023)
    This study investigated Australian hemp hurd (Cannabis sativa L., “Frog One”) as a lignocellulosic raw material for ultra-low-density hemp particleboard (ULHPB) with densities ranging from 213 to 309 kg/m3. The hurd was first milled and fractionated into three particle size categories, that is, fine (F), medium (M), and coarse (C). Twelve unique ULHPB variants were then fabricated comprising varying particle loadings from four particle size mixes, that is, 100% C, 100% M, 50%/50% CM, 25%/50%/25% CMF, and adhesive contents of bio-epoxy (EPX), phenol resorcinol formaldehyde (PRF), and emulsifiable methylene diphenyl diisocyanate (MDI), respectively. The panel assessments, conducted in accordance with the Australian reconstituted wood-based panels standard AS/NZS 1859.1 (2017), revealed a significant effect of particle dimension on most physico-mechanical properties. Furthermore, the resination method and pressing temperature controlled post-cure panel expansion and additional panel characteristics. Notably, MDI-ULHPB exhibited drastically different behavior and properties compared to EPX and PRF equivalents, demonstrating greater bending strength, stiffness, screw withdrawal strength, and dimensional stability. Importantly, all MDI variants conformed to the 15% thickness swelling limit for moisture resistant particleboard. Surface lamination of MDI-bonded ULHPB with sheets of aluminum, Masonite, and Kraft liner significantly improved the inherently low flexural properties, suggesting the potential suitability of ULHPB as a core layer in lightweight sandwich composite panels. The integration of agricultural by-products, such as hemp hurd, into engineered building materials presents a promising opportunity to mitigate the depletion of finite timber resources and aligns well with circular economy principles. Highlights • Utilizing agricultural residue as sustainable raw material in building products. • Hemp hurd enables ultra-low-density particleboard with thermosetting resins. • Coarse particle size mix enhances mechanical performance in panels. • Panel characteristics controlled by resination method and pressing temperature. • Lamination enhances functionality of lightweight hemp hurd sandwich panel.
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    Advancing enhanced wood manufacturing industries in Laos and Australia - Final Report
    Smith, H ; Leggate, W ; KANOWSKI, P ; Boer, K ; Ling, S ; Midgley, S ; Belleville, B ; Faircloth, A ; Robinson, R ; Lattanvongkot, B ; Boupha, L ; Phonetip, K (Australian Centre for International Agricultural Research (ACIAR), 2023-07-17)
    ACIAR invested in Lao PDR's plantation and wood products sector in 2005, with the third project, FST/2016/151 – Advancing enhanced wood manufacturing industries in Laos and Australia (VALTIP3), building on the results. The VALTIP3 project conducted research on plantation-wood value chains, mapping plantations, exploring actors like traders and women, developing innovative wood products, and implementing processing technologies. It also assessed policy, regulatory, and strategic settings in these areas. The projects built local capacity to meet the demand of plantation-wood processing companies in Laos for NUoL FFS graduates and government stakeholders seeking VALTIP3 team members' knowledge for policy changes.
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    Equilibrium Moisture Content Map for Laos
    Belleville, B ; Phonetip, K ; Souvansai, D (North Carolina State University, 2022-03-07)
    Providing the equilibrium moisture content values for territories is important for avoiding major problems due to dimensional changes in wooden products. This study evaluated the average equilibrium moisture content values for twelve months (from 1981 to 2020) for Laos and produced an equilibrium moisture content map. A model was used to generate the equilibrium moisture content values based on temperature and relative humidity data obtained from the POWER Data Access Viewer v2.0.0. for 18 provinces (148 districts) based on the geographic coordinates of each district in Laos. The lowest equilibrium moisture content (12% to 13%) values were found in Vientiane Capital City, Vientiane province, Louangprabang, Bokeo, Attapeu, Louang Namtha, Oudomxay, Houaphan, Sayaburi, Savannakhet, Salavan, and Champasak province. The rest of the districts, which had an equilibrium moisture content ranging from 13% to 16%, were mostly found on the eastern part of Laos and a small part of Northern Laos. The monthly swinging average value of the equilibrium moisture content ranged from 10% to 18% across the country. The equilibrium moisture content values for each district in Laos were also defined.
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    An investigation on peeling recovery and quality of senile plantation-grown rubber trees in Laos
    Belleville, B ; Chounlamounty, P ; Soukphaxay, K ; Phengthajam, V ; Saetern, L ; Smith, H ; Ozarska, B (Springer (part of Springer Nature), 2020)
    The study assessed the peeling potential of rubber trees past the prime latex-producing age when the latex yields become non-economical. Fifteen 25-year-old plantation-grown trees were harvested and peeled using spindleless lathe technology. Following peeling, veneer sheets were measured and graded to determine volume and quality recoveries. Relationships between billet characteristics and recoveries or quality were examined and a recovery predictive model proposed. Most of the main causes identified for downgrading face veneers were either processing-related issues or drying-induced defects. Thus, a combination of several optimisation techniques could annihilate most of the main causes of downgrading veneer, potentially leading to a substantial proportion of higher-quality veneers typically used where surface decorative appearance is a primary consideration. The results demonstrated that rubber trees past their latex-producing prime from unthinned and unpruned stands have qualities and desirable traits to potentially produce certain high-value engineered wood products. Senile rubber trees in Laos could represent significant additional revenue to growers and a source of raw material to the industry which, theoretically, could be converted into high-value products if other factors can be overcome.
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    Timber Trading and Pricing of Plantation Grown Teak (Tectona grandis Linn.F) in Laos
    Wanneng, P ; Ozarska, B ; Phimmavong, S ; Belleville, B ; Davidson, B (SPRINGER, 2021-12)
    The market demand and price of teak in Laos vary broadly and depend on several factors. The aim of this study was to assess timber trading and pricing based on a survey of teak buyers. The research investigated teak trading methods, markets and prices paid for particular timber types and quality grades. Three types of teak timber are commonly sold: 24.7% as standing trees, 39.6% as round logs and 35.7% as square logs. The main wood products produced from plantation teak include joinery products, door and window frames, and furniture (57.9%, 26.3% and 15.8% respectively). The end buyers of teak timber in Laos are sawmillers and wood manufacturer. Teak timbers supplied to end buyers from growers via the local traders account for 49.0%, followed by 41.3% by direct supply from teak growers and 9.7% via the local small sawmillers and wood manufacturers. The price of teak timber varies significantly based on four main factors: timber types, log sizes, log quality (grades) and distance from plantation site to road (for standing trees). The round log price of 250US$/m3, based on both log diameter size (D26-30 cm) and log quality grade (A grade), was much lower than the 321US$/m3 amount paid for the same size of round log (D26-30 cm) based on log diameter alone (no grading price). It can be concluded that there is a need to develop a clear system or standard for teak log grading and pricing in Laos.
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    Planing characteristics of Papua New Guinea timber species from plantations and regrowth forests
    Belleville, B ; Iru, R ; Tsiritsi, C ; Ozarska, B (SPRINGER, 2020-03)
    Although Papua New Guinea (PNG) has a rich and diverse forest cover, there is limited information on processing characteristics for plantations and regrowth forests available. Consequently, the PNG timber processing industry is restricted to a few species, producing low-quality products, which limits opportunities for the processors. Sound knowledge of machining characteristics based on some systematic methods has been identified as essential for assessing the ability in processing raw material into appearance products. Therefore, a testing program was conducted to assess the planing characteristics and most common causes for planing degrade of 25 species sourced from the Morobe and West New Britain provinces, PNG. A total of 18 wood species proved to machine very well with more than 90% of assessed boards being graded either “excellent and requiring very light sanding” or “good and requiring light sanding”. Eight species from this group obtained a perfect score, i.e. requiring very light sanding.
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    High-Tech Modular Building Components with High Contents of Australian Hardwoods
    Zhang, X ; LI, S ; Belleville, B ; Ozarska, B ; Gutowski, M ; Kuys, B (Forest & Wood Products Australia Limited, 2020-03-23)
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    Assessing the potential of hemp hurd (Cannabis sativa L.) for the production of environmentally friendly lightweight panels
    Fehrmann, J (The Industrial Hemp Western Australia Association Inc, 2020)
    Presentation prepared for the 2nd Australian Industrial Hemp Conference in Fremantle, WA from 25 -28 February 2020. Abstract and slides.