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journal of materials research and technology 2022;20:4630 e 4658
chain, particularly in the Asia Pacific region, is a major chal- lenge [37]. Manufacturers still stick to conventional raw ma- terials for particleboard production and hesitate to adopt alternative feedstocks. It is a malicious cycle where the manufacturers blame the inconsistent supply of raw mate- rials. At the same time, the planters are reluctant to convert their cultivations because there is no demand for them. This weak link must be solved for the agricultural e waste-based particleboard to flourish. Accumulating agricultural wastes without proper discarding measures could pose a serious environmental threat to developing countries [195]. Intro- ducing relevant policies should enhance awareness and market acceptability among stakeholders and the public. Despite the scientific and technological advances, there are substantial challenges regarding the wider industrial utiliza- tion of agricultural biomass in particleboard manufacturing. Fresh agricultural biomass has a higher moisture content which makes it heavier, incurring higher transportation and storage costs [196]. More importantly, raw material with high moisture content is less compressible during board pressing. Adjustments in the processing parameters might be neces- sary. In addition, agricultural biomass generally has a lower apparent density than conventional wood particles. Low density causes a high volume per unit weight of agricultural biomass than wood particles [9]. Therefore, a sufficient compaction ratio might not be achieved within a limited pressing time. Moreover, a higher volume of agricultural biomass requires more resin for sufficient coverage to attain adequate bonding. Using the same resin content for agricul- tural biomass used for wood particles means that every par- ticle is covered with less adhesive, which could adversely affect the final performance of the resultant boards. Another issue of the particleboard fabricated of agricul- tural biomass is its deteriorated dimensional stability and water absorption. This issue is more significant on the straw-, stalk-, husk- and shell-based particleboard and could be overcome by adding hydrophobic agents such as wax during the production process. Meanwhile, grass- and leave-based particleboard have relatively lower TS and WA values due to their waxy layer on the surfaces and lower cellulosic content. However, due to the waxy layer, water-based UF resin is un- suitable for use as a binder during grass- and leave-based particleboard production. Bagasse-based particleboard gives satisfactory physical and mechanical properties compared to the other agricultural biomass counterparts. Nevertheless, most agricultural biomass-based particleboard panels have relatively poorer mechanical strength than those of wood- based panels. The incorporation of woody particles is deemed necessary to improve the strength of particleboard. Meanwhile, the introduction of recycled wood particles in producing new particleboard shows promising results. Never- theless, it is interesting to note that the content ratio of recycled wood particles was not proportional to the physical and me- chanical properties values. Further studies onvarioustreatment conditions and different ratios of recycled wood particles are required to determine the optimum parameters to produce particleboard with the best physical and mechanical properties. An important issue with particleboard and other engi- neered wood products, fabricated from agricultural waste biomass and/or recycled wood waste is the lack of sufficient
bonded with two types of adhesives, i.e. polyvinyl acetate (PVA) and Fabricol AG222 (FAG222) as insulation materials. Through the assessment of impact categories, it was found that EPS had a higher impact on GWP, ODP, and HTP. Mark- edly, both PVA-bonded and FAG222-bonded particleboard showed satisfactory environmental impacts. However, the PVA-bonded panel exhibited better results when landfilling was the preferred disposal technique. In the production process of 1 m 3 particleboard, Shang et al. [192] discovered a reduction of 40 kg CO 2 equivalent (CO 2 eq) of greenhouse gas (GHG) emission between straw parti- cleboard (600 kg CO 2 eq GHG emission) and wood particle- board (640 kg CO 2 eq GHG emission). On the other hand, straw particleboard consumed less non-renewable energy (2700 MJ) than wood particleboards (2800 MJ). The LCA results demon- strated that the environmental impacts of using straw for manufacturing straw particleboard and cement-bonded particleboard were significantly reduced by 6% and 10%, respectively, compared with using wood as a feedstock. The share of wood resources in processing and drying of the raw material with regards to non-renewable energy consumption and GWP impact was higher than straw particleboards as the moisture content of natural wood is higher. Moreover, due to the omittance of the peeling machine, straw particleboard consumed lower non-renewable energy. The authors concluded that the straw particleboard is the optimal scheme for recycling and reusing crop straw resources. However, power consumption during forming process and straw transportation distance are the main constraints that affect its environmental performance and should be improved. In the case of using recycled wood waste in cement-bonded particleboard production, Hossain et al. [193] reported that recycling wood waste at a rate of 10% could save around 11,016 tonnes of CO 2 eq per year. The total savings of GHGs emissions for cement-bonded particleboard production could reach 55,079 tonnes of CO 2 eq per year if 50% of the total wood waste could be recovered and reutilized yearly for the production of cement-bonded particleboard. Reutilization of wood waste reduced the induced emission, increased carbon sequestra- tion, and avoided emission, which led to the increased saving of GHGs emissions. Hoglmeier et al. [194] compared the environmental performance of utilizing recovered wood in cascades versus primary wood in manufacturing particle- board. Overall, the environmental footprint caused by the cascading system was around 10% e 25% lower than the pri- mary wood system. The authors concluded that the cascading effects are minor compared to the use of primary wood. However, when considering land occupation and trans- formation, cascading proved to be an even more preferable treatment option for waste wood as a reduction of 99.1% and 51.2% was recorded, respectively. Markedly, applying agri- cultural biomass and recycled wood in particleboard manufacturing provides environmentally benign alternatives to conventional wood.
8.
Problems, prospects, and challenges
Particleboard manufacturers face an inconsistent supply of raw materials, and the absence of an established supply
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