Research Paper
Chemistry of wood
Majid Kiaei
Abstract
Abstract: Background and objective: This study aimed to extract, identify, and compare the chemical compounds in acetone-soluble extracts from the bark and wood of Populus alba using gas chromatography–mass spectrometry (GC-MS). Materials and Methods: Three healthy trees were selected from the ...
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Abstract: Background and objective: This study aimed to extract, identify, and compare the chemical compounds in acetone-soluble extracts from the bark and wood of Populus alba using gas chromatography–mass spectrometry (GC-MS). Materials and Methods: Three healthy trees were selected from the Marzanabad region. After preparing disks at breast height, bark and wood samples were separately collected and milled into powder. Organic compounds were extracted according to the TAPPI standard method using a Soxhlet apparatus. After derivatization of the compounds with the BSTFA reagent, the samples were injected into the GC–MS instrument. Identification of compounds was performed based on retention time, calculation of the Kovats retention index, and comparison of mass spectra with the device’s library and Adams’ table.Results: Results showed that the percentage of acetone soluble extractives in poplar bark was considerably higher than in its wood. In total, 17 chemical compounds in bark and 18 compounds in wood were identified. p-Xylene was found to be the predominant compound in both parts, accounting for over 36% of total extractives, with its content being significantly higher in bark than in wood. Additionally, compounds such as ethylbenzene, 1,2 dimethylbenzene, limonene isomers, aliphatic hydrocarbons, and certain fatty acids were commonly identified in both bark and wood, although their relative distribution differed between bark and wood samples.Conclusions: The superior content and diversity of extractives in poplar bark indicate that this part, despite its currently limited application, can be considered as a potential source of valuable aromatic and organic compounds for use in chemical, wood, and bioprocessing industries.Keywords: Populus alba, extractives, bark, gas chromatography-mass spectrometryAbstract: Background and objective: This study aimed to extract, identify, and compare the chemical compounds in acetone-soluble extracts from the bark and wood of Populus alba using gas chromatography–mass spectrometry (GC-MS). Materials and Methods: Three healthy trees were selected from the Marzanabad region. After preparing disks at breast height, bark and wood samples were separately collected and milled into powder. Organic compounds were extracted according to the TAPPI standard method using a Soxhlet apparatus. After derivatization of the compounds with the BSTFA reagent, the samples were injected into the GC–MS instrument. Identification of compounds was performed based on retention time, calculation of the Kovats retention index, and comparison of mass spectra with the device’s library and Adams’ table.Results: Results showed that the percentage of acetone soluble extractives in poplar bark was considerably higher than in its wood. In total, 17 chemical compounds in bark and 18 compounds in wood were identified. p-Xylene was found to be the predominant compound in both parts, accounting for over 36% of total extractives, with its content being significantly higher in bark than in wood. Additionally, compounds such as ethylbenzene, 1,2 dimethylbenzene, limonene isomers, aliphatic hydrocarbons, and certain fatty acids were commonly identified in both bark and wood, although their relative distribution differed between bark and wood samples.Conclusions: The superior content and diversity of extractives in poplar bark indicate that this part, despite its currently limited application, can be considered as a potential source of valuable aromatic and organic compounds for use in chemical, wood, and bioprocessing industries.Keywords: Populus alba, extractives, bark, gas chromatography-mass spectrometry
Research Paper
Wood Modification and Wood Preservation
meysam mehdinia; hossein mohammadi; mostafa sefidrouh
Abstract
AbstractLaminated Strand Lumber (LSL) is an engineered wood product widely used in construction and furniture industries. This study investigated the effect of adhesive type (phenol-formaldehyde and MDI) and preservative type (nano-zinc oxide, zinc borate, and nano-graphene) at four levels (0, 0.5, 1, ...
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AbstractLaminated Strand Lumber (LSL) is an engineered wood product widely used in construction and furniture industries. This study investigated the effect of adhesive type (phenol-formaldehyde and MDI) and preservative type (nano-zinc oxide, zinc borate, and nano-graphene) at four levels (0, 0.5, 1, and 1.5%) on the resistance of LSL to the subterranean termite Microcerotermes diversus. Specimens were manufactured from beech wood (Fagus orientalis) strands, and termite resistance tests were conducted according to AWPA standards for 21 days. Results showed that all three preservatives significantly reduced weight loss compared to controls. Nano-zinc oxide exhibited the best performance with an average weight loss of 0.91%, followed by zinc borate (1.42%) and nano-graphene (2.12%). Increasing preservative concentration from 0.5% to 1.5% improved weight loss reduction by up to 130% compared to controls. Additionally, specimens manufactured with PF adhesive showed higher resistance than those with MDI. Images confirmed reduced termite presence around nano-zinc oxide-treated specimens. Overall, nano-zinc oxide is recommended as the most effective preservative against termites in LSL manufacturing.AbstractLaminated Strand Lumber (LSL) is an engineered wood product widely used in construction and furniture industries. This study investigated the effect of adhesive type (phenol-formaldehyde and MDI) and preservative type (nano-zinc oxide, zinc borate, and nano-graphene) at four levels (0, 0.5, 1, and 1.5%) on the resistance of LSL to the subterranean termite Microcerotermes diversus. Specimens were manufactured from beech wood (Fagus orientalis) strands, and termite resistance tests were conducted according to AWPA standards for 21 days. Results showed that all three preservatives significantly reduced weight loss compared to controls. Nano-zinc oxide exhibited the best performance with an average weight loss of 0.91%, followed by zinc borate (1.42%) and nano-graphene (2.12%). Increasing preservative concentration from 0.5% to 1.5% improved weight loss reduction by up to 130% compared to controls. Additionally, specimens manufactured with PF adhesive showed higher resistance than those with MDI. Images confirmed reduced termite presence around nano-zinc oxide-treated specimens. Overall, nano-zinc oxide is recommended as the most effective preservative against termites in LSL manufacturing.AbstractLaminated Strand Lumber (LSL) is an engineered wood product widely used in construction and furniture industries. This study investigated the effect of adhesive type (phenol-formaldehyde and MDI) and preservative type (nano-zinc oxide, zinc borate, and nano-graphene) at four levels (0, 0.5, 1, and 1.5%) on the resistance of LSL to the subterranean termite Microcerotermes diversus. Specimens were manufactured from beech wood (Fagus orientalis) strands, and termite resistance tests were conducted according to AWPA standards for 21 days. Results showed that all three preservatives significantly reduced weight loss compared to controls. Nano-zinc oxide exhibited the best performance with an average weight loss of 0.91%, followed by zinc borate (1.42%) and nano-graphene (2.12%). Increasing preservative concentration from 0.5% to 1.5% improved weight loss reduction by up to 130% compared to controls. Additionally, specimens manufactured with PF adhesive showed higher resistance than those with MDI. Images confirmed reduced termite presence around nano-zinc oxide-treated specimens. Overall, nano-zinc oxide is recommended as the most effective preservative against termites in LSL manufacturing.
Research Paper
Pulp and paper
Ramin Vaysi
Abstract
Background and aim: Currently, in Iran, NSSC pulp and fluting paper are produced from mixed species and waste paper. Considering the forest breathing plan in recent years, competition from other industries in supplying consumable wood raw materials and as a result of price increases, this industry has ...
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Background and aim: Currently, in Iran, NSSC pulp and fluting paper are produced from mixed species and waste paper. Considering the forest breathing plan in recent years, competition from other industries in supplying consumable wood raw materials and as a result of price increases, this industry has faced a shortage and challenge of consumable lignocellulosic raw materials, which is currently partially supplied by using waste paper.On the other hand, due to the cutting down of some citrus trees, especially oranges, and the expansion of kiwi cultivation in their place, large amounts of citrus wood are produced annually in the north of the country, which is mostly used in the particleboard, fiberboard, or firewood industries. Due to its good accessibility, ease and low cost of transportation, the use of these woods in pulp and paper production can also be considered and is important. For this purpose, this study was conducted to investigate the possibility of producing NSSC pulp and fluting paper from citrus wood (orange) in the Mazandaran Wood and Paper Industries (MWPI).Materials and Methods: To conduct this research, a random amount of wood chips were prepared from citrus (orange) wood in western Mazandaran (Tonkabon region) and using the MWPI cooking conditions, NSSC pulp was prepared. In the first stage, the biometric properties of their fibers were measured. In the next step, the refined NSSC pulp of orange wood was mixed with the NSSC pulp of MWPI in proportions of 60, 45, 30, 15, 75 and 100 percent. From the selected samples and according to TAPPI standard tests, handsheets with a basis weight of 113 g/m2 was prepared. Then, the optical properties of the prepared papers, especially the brightness, yellowness and opacity, as well as the resistance properties, especially the resistance to tearing, bursting, tensile and breaking length of the resulting papers, were measured and compared using TAPPI standard tests.Results: The results of fiber biometrics showed that the average fiber length, flexibility coefficient, and Rankel coefficient of orange wood were 734.8 microns, 46.9, and 136.02 microns, respectively. The results of this study showed that under the cooking conditions of MWPI and at a temperature of 170 degrees Celsius and a cooking time of 112 minutes, NSSC pulp can be produced with an efficiency of 76%. The results showed that the highest values of breaking length, ring crush test (RCT) and tensile strength were observed in the paper obtained from orange NSSC pulp. The highest tear, burst strengths and CMT were observed in the paper obtained from a mixture of 75% orange NSSC pulp + 25% factory NSSC pulp, and the lowest values were observed in the fluting paper obtained from factory NSSC pulp. Therefore, according to the above results, in addition to the fact that pure NSSC citrus pulp (orange) can be substituted for the aforementioned factory NSSC pulp, even with an increase of 15-100% of NSSC citrus pulp (orange) to the factory NSSC pulp, most of the above resistances show a significant increase. However, the best properties of fluting paper were observed in the paper obtained by mixing 75% orange NSSC pulp + 25% factory NSSC pulp.Discussion: Considering that the biometric characteristics of orange wood fibers are similar to some of the hardwoods forests of the northern part of the country, and even its fiber length and Rankel coefficient are much better than many industrial hardwoods species, which has improved many of the resistances obtained. Therefore, a 75% mixture of citrus NSSC pulp (orange) can be used to replace part of the NSSC pulp of MWPI, in order to reduce the problem of gardeners regarding the more suitable sale of citrus wood (orange), and to provide the possibility of using citrus NSSC pulp (orange) instead of part of the NSSC pulp produced by the aforementioned factory. Therefore, by supplying a portion of the raw materials for the pulp and paper industries from citrus orchards in the interior (north) of the country, the outflow of a significant amount of foreign exchange from the country for the purchase and supply of raw materials for paper factories will be prevented.
Research Paper
Composite wood products
Iman Rezvani; Mehdi Jonoobi; Alireza Ashori; Peyman َAhmadi; sima sepahvand
Abstract
Background and Objectives: The pulp and paper industry generate substantial amounts of paper sludge annually, the disposal of which imposes considerable economic costs and environmental challenges. Recycling this waste in cementitious materials offers a sustainable approach to reducing cement consumption, ...
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Background and Objectives: The pulp and paper industry generate substantial amounts of paper sludge annually, the disposal of which imposes considerable economic costs and environmental challenges. Recycling this waste in cementitious materials offers a sustainable approach to reducing cement consumption, mitigating CO₂ emissions associated with cement production, and promoting industrial waste valorization. Although numerous studies have investigated the incorporation of paper sludge into cement-based materials, limited information is available regarding the combined effects of paper sludge replacement ratio and particle size on the physical and mechanical properties of cementitious composites, as well as the capability of statistical models to predict these effects. Therefore, the objective of this study was to evaluate the influence of paper sludge replacement ratio and particle size on the compressive strength, modulus of rupture, modulus of elasticity, water absorption, density, and porosity of cementitious composites, and to assess the applicability of Response Surface Methodology (RSM) for modeling and analyzing these responses.Materials and Methods: In this study, cement-based composites were produced using paper mill sludge at three replacement levels of 10%, 20%, and 30% by weight of cement, along with a control sample (0% sludge), and four particle-size ranges of 0.5, 1, 1.5, and 2 mm. The experiments were conducted based on a full factorial design with three replicates, resulting in a total of 48 specimens. After curing, compressive strength, modulus of rupture, modulus of elasticity, 72-h water absorption, density, and porosity were measured. To investigate the effects of replacement percentage and particle size and to evaluate their interaction effects, analysis of variance (ANOVA) and a second-order regression model within the response surface methodology (RSM) framework were employed. The significance of the models and factor effects was evaluated at the 0.05 significance level, while the goodness of fit of the models was assessed using the coefficients of determination (R²) and adjusted coefficients of determination (Adjusted R²).Results: The results showed that the percentage of paper mill sludge replacement was the dominant factor for most of the responses investigated, whereas the effect of particle size was generally limited within the studied range and was significant only for the modulus of elasticity (P = 0.023). The interaction effect between replacement percentage and particle size was not statistically significant for any of the responses (P > 0.05). As the replacement percentage increased, compressive strength and density exhibited decreasing trends, whereas water absorption and porosity increased. Compressive strength decreased from approximately 18.34 to 10.26 MPa, while water absorption increased from 8.85% to 38.21% and porosity from 11.89% to 35.93%. The density of the composites also decreased with increasing sludge content, indicating a reduction in the specific gravity of the resulting composites. At low replacement levels, particularly around 10%, a relative increase in compressive strength and modulus of rupture was observed; however, this trend was not statistically significant for the modulus of rupture. At higher replacement levels, increasing sludge content was associated with increased porosity and water absorption, accompanied by an overall decline in mechanical performance. In the RSM analysis, the water absorption model showed the best fit (R² = 83.9% and Adjusted R² = 72.5%), whereas the models for some responses were not statistically significant and therefore had limited predictive capability. Overall, the results demonstrated that the percentage of paper mill sludge replacement was a more influential factor than particle size in determining most of the properties of the cement-based composites.Conclusions: The findings demonstrate that the paper sludge replacement ratio is the dominant parameter controlling the physical and mechanical performance of cementitious composites, whereas the influence of particle size between 0.5 and 2 mm is relatively limited. Incorporating low amounts of paper sludge, particularly around 10% replacement, maintained satisfactory mechanical performance while reducing cement consumption. In contrast, higher replacement levels increased water absorption and porosity, resulting in lower strength and stiffness. Overall, paper sludge shows considerable potential as a sustainable cement replacement material and can contribute to reducing cement consumption, promoting the valorization of paper industry waste, and supporting the development of environmentally friendly cementitious materials, particularly for non-structural applications. Keywords: Response Surface Methodology; paper sludge; cementitious composites; mechanical properties; sustainable development; optimization.
Research Paper
Physics and Mechanical Wood
Shahrzad Omrani Ghahjaverestani; Amir Lashgari; Mehran Roohnia; Ajang Tajdini; Seyyed Khosrow Hossein Ashrafi
Abstract
Abstract:Background and objectives: Wood remains the preferred material for acoustic resonators and soundboards due to its orthotropic behavior, low density, high stiffness, and exceptional low vibration damping properties. To simultaneously optimize surface protection and acoustic efficiency, wood surface ...
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Abstract:Background and objectives: Wood remains the preferred material for acoustic resonators and soundboards due to its orthotropic behavior, low density, high stiffness, and exceptional low vibration damping properties. To simultaneously optimize surface protection and acoustic efficiency, wood surface modification using natural spirit )alcohol-based( multilayer coatings has been proposed as an efficient solution. However, the type of formulation and layering of the coating can have different effects on the vibration properties. This study aimed to evaluate and compare the effects of two natural multilayer spirit coating systems (orange spirit coating and dragon’s blood resin spirit coating) on the physical, mechanical, and dynamic-acoustical properties of spruce (Picea abies) wood to identify the optimal coating formulation.Methodology: Ten healthy, defect-free samples of spruce (Picea abies( wood were prepared, measuring 150×12×2 mm (longitudinal, radial, and tangential) along the grain timber. After surface treatment, the samples were stored in a climate-controlled room (21°C and 65% relative humidity). Non-destructive forced flexural vibration testing was performed before coating application and the samples were classified based on standard criteria. The samples were divided into two groups of five; the first group was coated with multi-layer orange spirit coating and the second group was coated with multi-layer dragon’s blood spirit coating (including treatment steps, filler, middle layer (sealing) and final coating (topcoat)). The traditional French polishing technique was used to apply the coatings. After dring and condition of the samples at the end of each coating stage, the forced vibration test was repeated. The acoustic signals were recorded using Audacity software and analyzed using the NDT-lab® system. The parameters of density, dynamic elastic modulus, vibration velocity, acoustic coefficient, damping coefficient, acoustic conversion efficiency and mechanical impedance were calculated and the data were compared with Excel software and regression analysis. Results: The results showed that the application of both types of coatings caused changes in the physical and acoustic properties of spruce wood, but the stability and trends of these changes differed between the two coatings. In the orange spirit coating, the density and vibration velocity increased with a high coefficient of determination (R2 = 0.94) and the specific elastic modulus was maintained. The acoustic coefficient decreased relatively in both coatings, but in the orange spirit coating this decrease was more limited and accompanied by a higher coefficient of determination (R2 = 0.90). The damping coefficient evaluation showed that the orange spirit coating provided a more uniform distribution and better stability in the vibration behavior without causing sudden drastic changes (R2 = 0.96), while the dragon’s blood spirit coating showed heterogeneous fluctuations in damping. Furthermore, the acoustic conversion efficiency of the orange spirit coating remained closer to the raw wood values at different stages (R2 = 0.91). Mechanical impedance also showed a more uniform increase and better stabilization in samples coated with orange spirit coating compared to dragon’s blood spirit coating. Conclusion: Both natural spirit coatings were able to maintain the lightweight structure of the wood. However, the orange spirit coating, due to the formation of a more uniform layer and more controlled penetration, provided substantially better performance in maintaining and improving mechanical stability, vibration velocity, acoustic coefficient, and acoustic conversion efficiency. This coating caused minimal adverse changes in the damping coefficient. Overall, the spirit alcohol coating is recommended as a superior natural coating for optimizing the acoustic performance of spruce wood soundboards in musical instrument construction and architectural acoustic applications.Summary: These findings indicate that the use of appropriately formulated multi-layer natural coatings can improve the surface protection of resonator wood without significantly degrading its acoustic properties. Therefore, the results of this study provide a valuable basis for the design and development of sustainable natural coating systems for use in musical instruments and other acoustic engineering applications requiring high vibrational stability and durability.
Pulp and Paper
Pulp and paper
Ramin Vaysi; Davood Majlesi
Abstract
Background and aim: The increasing reliance of the papermaking industry on recycled fiber furnishes, together with the progressive degradation of fiber quality through multiple recycling cycles, represents a major challenge in maintaining adequate strength performance in paper products. Reductions in ...
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Background and aim: The increasing reliance of the papermaking industry on recycled fiber furnishes, together with the progressive degradation of fiber quality through multiple recycling cycles, represents a major challenge in maintaining adequate strength performance in paper products. Reductions in fiber length, flexibility, and bonding capacity weaken inter-fiber bonding and consequently diminish the structural integrity of recycled-fiber papers. These issues are particularly critical in packaging grades that demand high mechanical strength. Chemical strengthening agents and fiber-reinforcement strategies offer potential solutions; however, the optimal dosages of cationic starch and alum, as well as the appropriate proportion of imported long fibers required to enhance sheet performance, remain insufficiently explored. This study therefore aimed to investigate the individual and interactive effects of these three additives on the physical and mechanical properties of handsheets produced from recycled pulp.Materials and Methods: Recycled pulp supplied by Kaveh Paper Mill was refined to approximately 300 mL CSF and used as the base furnish. Cationic starch, following preparation and gelatinization, was added to the furnish at four dosage levels (0, 1, 1.5, and 2% based on oven-dry fiber). Alum (aluminum sulfate, 17% purity) with acidic pH was applied at three levels (0, 1.5, and 2%). Imported long fibers were repulped and blended with the recycled furnish at 0, 10, and 15%. Laboratory handsheets with a basis weight of 130 g/m² were produced according to TAPPI standards. Mechanical properties—including tensile strength, tear index, burst strength, Ring Crush Test (RCT), and Corrugated Medium Test (CMT)—were evaluated, along with physical properties such as water absorption and sheet thickness. Statistical analyses were conducted using a factorial experimental design with ANOVA and Duncan’s multiple range test.Results: Cationic starch significantly improved all measured strength properties, with the 1.5% dosage yielding the greatest enhancement. This improvement is attributed to increased cationic charge density, enhanced fiber–fiber bonding, and densification of the fiber network through stronger hydrogen bonding. In contrast, alum at dosages above the optimal level reduced mechanical performance; the 2% treatment, in particular, produced marked decreases in tensile, tear, and burst strengths. These reductions may be linked to excessive alum deposition, charge reversal effects, and impaired inter-fiber bonding resulting in a more brittle fiber matrix.The addition of imported long fibers led to substantial improvements in mechanical strength by contributing longer, more flexible, and more collapsible fibers to the network. The 15% addition provided the most pronounced reinforcement, especially when combined with 1.5% cationic starch, which yielded the highest overall strength values. In terms of physical behavior, cationic starch reduced water absorption and increased sheet density due to enhanced fiber consolidation, whereas alum increased water absorption owing to its hydrophilic nature. The incorporation of long fibers increased sheet thickness as a result of forming a bulkier fiber structure.Conclusion: Overall, the findings demonstrate that an optimized combination of chemical additives and fiber reinforcement can significantly enhance the quality of papers produced from recycled pulp. The synergistic application of 1.5% cationic starch and 15% imported long fibers was identified as the most effective treatment for improving both mechanical strength and physical performance. These results offer practical guidance for improving the efficiency of recycled-fiber-based papermaking systems and reducing dependence on virgin fibers in industrial production.
Composite Wood Products
Composite wood products
Mobina Azimi; Steve Severtson; Elmira Kaffash Saea
Abstract
One of the main causes of environmental damage and pollution is petroleum-based plastics and packaging materials. Despite the numerous advantages of petroleum-based plastics in the packaging industry, such as affordable cost, high mechanical strength, and moisture resistance, their non-biodegradability ...
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One of the main causes of environmental damage and pollution is petroleum-based plastics and packaging materials. Despite the numerous advantages of petroleum-based plastics in the packaging industry, such as affordable cost, high mechanical strength, and moisture resistance, their non-biodegradability leads to persistent accumulation in the environment and poses serious risks to ecosystems and human health. In this regard, nanobiopolymers such as nanocellulose and bio-nanocomposites derived from it, due to their biocompatibility, renewability, and reasonable production costs, are promising alternatives for various applications including packaging. Despite the numerous technical and environmental advantages of nanocellulose, energy consumption and relatively high production costs remain global challenges to the commercial development of this nanobiopolymer. To address this, Kaffash-Saie et al. (2021) successfully produced cellulose nanofibers directly from sawdust through a simultaneous oxidation/purification process. The present study aims to directly produce cellulose nanocrystals from wood sawdust, which differ from cellulose nanofibers both in production stages and in morphological and technical characteristics. Direct production of cellulose nanocrystals from sawdust implies reduced energy consumption, chemical usage, water consumption, wastewater generation, and ultimately lower production costs compared to samples produced by conventional methods. The prepared cellulose nanocrystals were then used to reinforce carboxymethyl cellulose (CMC)-based films.Materials and Methods: The wooden raw material used in this study was Fir wood sawdust (Abies alba), obtained from the furniture industry workshop of the university. Chemical materials included sodium hydroxide, sodium hypochlorite, and hydrogen peroxide (purchased from Mojallali Co.), as well as sodium sulfite, sodium bromide, and TEMPO (purchased from Sigma-Aldrich). For the direct production of cellulose nanocrystals from sawdust, the purification and oxidation steps were performed simultaneously. At the end of this stage, an oxidized bleached cellulose pulp was obtained, in which the hydroxyl group at the C6 position of the pyranose ring was replaced by a carboxyl group. For comparison, cellulose nanocrystals were also produced indirectly (conventional method) from Fir sawdust. After producing both types of nanocrystals, they were added to carboxymethyl cellulose polymer at weight ratios of 0.5%, 1%, 3%, 5%, and 10% to produce nanocomposites via solution casting. Finally, the characteristics of the nanocrystals and the prepared nanocomposites were investigated and compared. Analytical methods used included Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and static tensile testing.Results: TEM images showed that the average diameter of nanocrystals produced by direct and indirect methods was 8±4 nm and 7±4 nm, respectively, with no significant dimensional or morphological differences observed between them. FE-SEM images showed uniform dispersion of nanocrystals within the CMC matrix. XRD patterns confirmed an increase in the crystallinity of nanocomposites with increasing cellulose nanocrystal content, while FTIR spectra revealed no significant structural differences between the samples. The results of static tensile testing showed that the neat CMC film had a tensile strength of 34 MPa. Upon the addition of 1% and 10% cellulose nanocrystals by both methods, tensile strength increased, with the increase being more pronounced at 10% nanocrystal content. At 10% mixing ratio, the tensile strength for direct and indirect method nanocrystals reached 58 MPa and 62 MPa, respectively.
Research Paper
Nano composite
Armin Jamali; Hossein Yousefi; Mahdi Mashkour; Steven J. Severtson; Alain Dufresne; Prashant Kumar
Abstract
Background and Objective: One of the most effective and direct methods to combat various types of air pollution is the use of filters. However, commercially available versions are manufactured from petroleum-based raw materials, and their waste has become a global challenge. In this regard, replacing ...
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Background and Objective: One of the most effective and direct methods to combat various types of air pollution is the use of filters. However, commercially available versions are manufactured from petroleum-based raw materials, and their waste has become a global challenge. In this regard, replacing these materials with bio-based raw materials can potentially not only solve the waste problem but also enhance filtration efficiency. Among these materials are cellulose nanofibers. The focus of most research has been on fabricating air filters via casting method using wood cellulose nanofibers. Studies on bacterial cellulose nanofibers and, fundamentally, investigations into different coating methods of these nanobiomaterials are very limited. Therefore, the present study aimed to investigate and compare the effects of two coating methods—dip coating and fog-spray coating—for fabricating air filter media using wood cellulose nanofibers and bacterial cellulose nanofibers.Materials and Methods: For this purpose, wood cellulose nanofibers (WCNF) produced by mechanical method with a degree of polymerization of 700-1200 nm and bacterial cellulose nanofibers (BCNF) synthesized by bacteria with a degree of polymerization of 1500-2500 nm were procured from Nanonovin Polymer Company. Cellulosic fabric with a grammage of 30 g/m² was prepared as the substrate for coating from Live Company and cut into dimensions of 15×15 cm. To fabricate the samples, the nanobiomaterials were first diluted to a concentration of 0.5% by weight using distilled water and then coated onto the cellulosic fabric substrate at a grammage of 2 g/m² using dip coating and fog-spray coating methods. The samples were then transferred to a freeze dryer and prepared at -50°C and 0.04 mbar for 24 hours. To evaluate the raw materials used in this study, tests such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), and zeta potential measurement were employed. To evaluate and compare the performance of the fabricated samples, tests including field emission scanning electron microscopy (FESEM), particle removal efficiency, pressure drop measurement, and filter quality factor calculation were used.Results: The results of FTIR and XRD tests showed that the raw materials used, including the fabric substrate, wood cellulose nanofibers, and bacterial cellulose nanofibers, are all cellulose type Iβ, whose chemical similarity potentially enhanced the formation of hydrogen bonds between the nanobiomaterials and the substrate. FESEM images indicated more uniform distribution and a network structure with finer pores in the samples coated via the fog-spray method compared to the dip coating method. Filtration performance evaluation demonstrated that both coating methods achieved over 90% removal efficiency for all particles in the range of 0.3 to 10 microns. The fog-spray method showed superior performance for both types of nanomaterials, which is attributed to the formation of a more uniform surface layer with more precise grammage control. Bacterial cellulose nanofibers, due to their higher degree of polymerization (1500-2500 nm) and more negative zeta potential (-25 compared to -12), showed higher removal efficiency than wood cellulose nanofibers in both coating methods. The best performance belonged to the bacterial cellulose nanofiber sample coated via the fog-spray method, which achieved a removal efficiency of 99.56% for 300 nm particles and a pressure drop of 112 Pa, earning the highest quality factor among all samples. The removal efficiency of 300 nm particles for BCNF-D, BCNF-F, WCNF-D, and WCNF-F samples were 93.92%, 99.56%, 91.63%, and 95.4%, respectively, and their pressure drops were 88±8, 112±7, 96±4, and 118±8 Pa, respectively.Conclusion: Both dip coating and fog-spray coating methods demonstrated high potential for fabricating bio-based air filter media. However, the media fabricated via the fog-spray method were more efficient than those fabricated via the dip coating method for both nanobiomaterials. On the other hand, the removal efficiency of samples fabricated using bacterial cellulose nanofibers was also higher than those fabricated using wood cellulose nanofibers. The fog-spray method for wood cellulose nanofibers enabled the fabrication of filters with N95 performance and for bacterial cellulose nanofibers enabled the fabrication of filters with N99 performance in this study.
Research Paper
Management and Economics wood
Azim Zarei; Sadegh Imani Parkohi; Elham Sadat Kia
Abstract
Problem definition and objectives: Given the importance of the wood and paper industries in the economy of Mazandaran province and their key role in employment and regional development, these industries, despite having numerous potentials such as access to natural resources and existing infrastructure, ...
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Problem definition and objectives: Given the importance of the wood and paper industries in the economy of Mazandaran province and their key role in employment and regional development, these industries, despite having numerous potentials such as access to natural resources and existing infrastructure, have faced multiple challenges in recent years. Heavy reliance on natural resources, vulnerability to environmental hazards, fluctuations in raw material prices, and widespread supply chain disruptions have posed serious threats to the sustainable performance of these industries. In such a complex and dynamic environment, sole reliance on traditional management methods, which mainly focus on internal productivity and operational control, is no longer sufficient to meet today's needs. This inadequacy reveals the necessity of adopting a systematic, integrated, and strategic approach capable of simultaneously managing the complexities of the external environment and the networked relationships of the value chain. Understanding this gap and the mentioned necessity, this study investigates the strategic and macro role of supply chain management as a comprehensive solution to overcome these challenges and enhance performance. The main objective of this research is to analyze the impact of supply chain management on the performance of the wood and paper industries in Mazandaran province, considering the mediating role of organizational competence and the moderating role of supply chain resilience.
Methodology: This research is applied in terms of purpose and descriptive-survey and causal in terms of method. The statistical population of the study includes 85 employees, financial managers, and senior managers of the wood and paper industries of Mazandaran province in the winter of 2025. From among them, using the Morgan table, 70 individuals were selected as the statistical sample through convenience sampling. Data were collected using four standard questionnaires (Lee, 2021; Kaplan & Norton, 2001; and Prayag et al., 2018). For data analysis, content validity was first confirmed by faculty experts. Then, using KMO and Bartlett's tests, construct validity was examined through confirmatory factor analysis (CFA), and discriminant validity was assessed using the AVE index. Reliability was also evaluated using Cronbach's alpha and composite reliability (CR). Finally, the data were analyzed at both descriptive and inferential levels using SPSS 25 and SmartPLS 4 software, employing a structural equation modeling approach (PLS-SEM).
Results: The results showed that supply chain management has a direct and significant impact on organizational competence and organizational performance. Furthermore, organizational competence, as a mediating variable, partially strengthens the impact of supply chain management on performance. More importantly, supply chain resilience plays a strong moderating role in the relationship between supply chain management and performance, meaning that the organization's ability to cope with disruptions significantly increases the positive impact of SCM on performance.
Conclusion: These findings recommend that managers of Mazandaran's wood and paper industries focus simultaneously on improving SCM strategies, strengthening organizational competencies, and increasing supply chain resilience against unforeseen events to achieve higher performance. These measures not only lead to improved performance but also bring sustainable competitive advantage to the organization. It is suggested that managers adopt an integrated and simultaneous approach in two areas to improve organizational performance: 'supply chain management' (with an emphasis on enterprise resource planning, inventory management, and warehousing systems) and 'organizational competencies' (including production, marketing, and R&D capabilities). Furthermore, given the moderating role of supply chain resilience, it is essential for managers to enhance the organization’s ability to face unexpected and risky conditions in the supply chain by developing strategic programs.
Research Paper
Management and Economics wood
Ahmad Samariha; Majid Farzi
Abstract
AbstractBackground and Objective: The development of high-value-added and environmentally compatible wood products has gained increasing importance in line with the principles of sustainable development in bio-based industries. ThermoWood, owing to its enhanced durability and dimensional stability and ...
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AbstractBackground and Objective: The development of high-value-added and environmentally compatible wood products has gained increasing importance in line with the principles of sustainable development in bio-based industries. ThermoWood, owing to its enhanced durability and dimensional stability and its reduced reliance on chemical preservatives, is considered an important product in this context. Despite the growing market for this product in Iran, economic studies based on cash-flow analysis and investment risk assessment for the establishment of ThermoWood manufacturing plants remain limited. Therefore, this study aimed to evaluate the economic and financial feasibility of establishing a ThermoWood manufacturing plant with a nominal production capacity of 625,000 m² per year in Mahdasht Industrial Park, Karaj.Materials and Methods: This applied study was conducted using a descriptive–analytical approach. The plant's operating capacity under the target utilization rate of 80% was assumed to be 500,000 m² per year. Fixed investment and working capital requirements were estimated at 1,494.36 billion tomans and 614.96 billion tomans, respectively, resulting in a total investment requirement of 2,109.32 billion tomans. The economic evaluation was conducted over a 22-year horizon, comprising two years of construction and 20 years of operation, using a 25% discount rate. The Net Present Value (NPV), Internal Rate of Return (IRR), Payback Period, Return on Investment (ROI), and Break-Even Point (BEP) were calculated. In addition, the sensitivity of the results to changes in the product selling price, raw wood price, and exchange rate was examined.Results: The results indicated that the Return on Investment (ROI) in the representative year of operation was approximately 24%, while the break-even point was approximately 24% of nominal production capacity. Based on an evaluation from the perspective of the total investment, the project yielded an NPV of 21,185 billion tomans, an IRR of 65.3%, and a payback period of 4.46 years. From the shareholders' perspective, the NPV was 22,165.48 billion tomans, the IRR was 170.4%, and the payback period for shareholders' equity contribution was calculated at 2.72 years. Sensitivity analysis demonstrated that the product selling price was the most influential variable affecting the economic value of the project. In an approximate analysis based on a stable cash-flow framework, a 30% decrease in the product selling price reduced the NPV to approximately −398.63 billion tomans, whereas a 30% increase in the selling price increased the NPV to approximately 3,450.23 billion tomans. Under the pessimistic scenario, involving a 20% decrease in the product selling price, a 20% increase in the raw wood price, and a 25% increase in the exchange rate, the approximate NPV reached −260.01 billion tomans.Conclusion: Based on the assumptions and prices prevailing in 1405 (2026), the establishment of a ThermoWood manufacturing plant in Mahdasht Industrial Park was found to be economically feasible. However, the high sensitivity of the economic indicators to the product selling price and raw wood procurement costs indicates that achieving the projected returns depends substantially on effective sales-market management and securing a reliable and sustainable supply of raw materials. Furthermore, given that 70.8% of the investment is allocated to fixed assets and that imported equipment constitutes a substantial portion of the capital expenditure, effective foreign-exchange risk management and equipment procurement planning are important factors in mitigating investment risk. The findings should be interpreted within the framework of the assumptions underlying the financial model, particularly the assumed nominal growth rates of product selling prices and operating costs.
Research Paper
Pulp and paper
Behrouz Sohrabi; Yahya Hamzeh; Mohammad Azadfallah; Ali Abdolkhani
Abstract
ABSTRACTBackground and Objectives: Repeated drying and re-pulping cycles cause hornification, which reduces fiber swelling, flexibility, and bonding ability. Consequently, papers produced from recycled pulp, may exhibit lower strength properties than papers made from virgin fibers. The use of strength ...
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ABSTRACTBackground and Objectives: Repeated drying and re-pulping cycles cause hornification, which reduces fiber swelling, flexibility, and bonding ability. Consequently, papers produced from recycled pulp, may exhibit lower strength properties than papers made from virgin fibers. The use of strength additives is a common approach to compensate for this loss in performance. Although cationic additives generally show good performance because of their favorable adsorption onto the anionic surface of cellulose fibers, anionic additives have a lower tendency to adsorb directly onto the fiber surface when used alone. Therefore, the combined use of cationic and anionic additives may improve the performance of anionic materials. The objective of this study was to investigate and compare the performance of cationic and anionic additives used individually and in combination, and to determine suitable application conditions for improving the strength properties of paper produced from recycled OCC pulp.Materials and Methods: Recycled OCC pulp was used as the raw material. Cationic starch, anionic starch, carboxymethyl cellulose (CMC), and alum were selected as wet-end additives. First, handsheets without additives were prepared as control samples, and their strength properties were determined. The effects of each additive, applied individually at different dosages, on burst strength were then evaluated, and an appropriate dosage was determined based on the results. In the second stage, combined systems consisting of alum and anionic starch, as well as a three-component system containing CMC, alum, and anionic starch, were investigated. For the alum-anionic starch system, the effects of both additive dosage and addition sequence were evaluated. In the final stage, selected conditions for the cationic starch-CMC, alum-anionic starch, and three-component cationic starch-alum-anionic starch systems were compared in terms of burst strength, tensile strength, ring crush test (RCT), corrugated crush test (CCT), and corrugating medium test (CMT). Water absorption was also evaluated using the Cobb60 test.Results: The results showed that cationic starch and CMC, when used individually, were capable of substantially increasing burst strength. For cationic starch, the increase in burst strength was pronounced up to a dosage of approximately 2%, while further increases resulted in a lower rate of improvement. Similarly, CMC produced its greatest improvement at approximately 1%, with additional increases in dosage providing only limited benefits. This behavior indicates diminishing marginal returns and a tendency toward quasi-saturation at higher additive dosages. In contrast, anionic starch and alum, when used individually, produced only limited improvements in burst strength. However, their combined application resulted in a substantial increase in strength. The results also demonstrated that the addition sequence played an important role. Adding alum to the pulp first, followed by anionic starch, produced better performance than adding anionic starch before alum or premixing the two additives prior to their addition to the pulp. In the final comparison, 1% CMC increased burst strength by approximately 48%, whereas 2% cationic starch, the alum–anionic starch system, and the three-component cationic starch–alum–anionic starch system increased burst strength by approximately 54%, 58%, and 77%, respectively. The three-component system also provided the greatest overall improvement in other strength properties, increasing tensile strength by approximately 70%, RCT by 100%, CCT by 71%, and CMT by 139%. None of the additive combinations investigated produced a significant change in the water absorption of the paper.Conclusion: The results demonstrated that the performance of wet-end strength additives in recycled pulp depends not only on their ionic nature and dosage, but also on their application method, combination, and addition sequence. While cationic starch and CMC showed good performance when used individually, the combination of alum and anionic starch largely overcame the limited performance of anionic starch when used alone. The three-component cationic starch–alum–anionic starch system produced the greatest overall improvement in paper strength properties. However, increasing the number of components in a chemical system does not necessarily result in a proportional increase in economic efficiency. The selection of an appropriate system should therefore consider the balance among strength improvement, additive consumption, and process complexity. Overall, the findings demonstrate that targeted management of the type, dosage, and addition sequence of cationic and anionic additives at the wet end can provide an effective strategy for improving the strength performance of papers produced from recycled OCC pulp.
Research Paper
Nano composite
Fatemeh Kazemnezhad khorami; sepideh Hamedi; kermanian hossein; Omid Ramezani; Zahra Razmpour; Farzaneh Havaseli.Ashtiani
Abstract
Background and objectives: Rapid changes in lifestyle have increased the demand for processed and packaged foods. The barrier properties of packaging limit the exposure of food components to external factors, such as microorganisms, air, and light, thereby delaying food spoilage. In recent years, edible ...
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Background and objectives: Rapid changes in lifestyle have increased the demand for processed and packaged foods. The barrier properties of packaging limit the exposure of food components to external factors, such as microorganisms, air, and light, thereby delaying food spoilage. In recent years, edible films based on natural polymers, particularly polysaccharides, have attracted considerable attention owing to their biodegradability, safety, and environmental advantages. Edible coatings form a thin protective layer on food products, helping to protect them from spoilage factors and extend their shelf life. They also offer a potential alternative to petroleum-based packaging materials and may help mitigate their associated environmental concerns. Therefore, this study aimed to investigate the effects of halloysite nanotubes (HNTs) on the properties of an edible film based on flaxseed mucilage (FM).Methodology: Flaxseed mucilage was extracted by water soaking followed by ethanol precipitation. Biodegradable edible films based on FM were subsequently prepared using the solvent-casting and evaporation method. The effects of different HNT concentrations (1, 3, and 5 wt%) on the moisture absorption, barrier, optical, and thermal properties of the FM films were evaluated. Fourier-transform infrared (FTIR) spectroscopy was used to investigate potential interactions between FM and HNTs. The thermal stability of the films was evaluated by thermogravimetric analysis (TGA) from room temperature to 600 °C under a nitrogen atmosphere. The distribution of HNTs within the polymer matrix was qualitatively assessed by elemental mapping of Si and Al using energy-dispersive X-ray spectroscopy (EDX). Moisture absorption was determined by sequential weighing at 75% relative humidity, while water vapor permeability (WVP) was measured according to ASTM E96. The mechanical properties were evaluated according to ASTM D882. Film color parameters, including lightness (L*), redness–greenness (a*), and yellowness–blueness (b*), were determined using a colorimeter. The antibacterial activity of the films against the Gram-negative bacterium Escherichia coli and the Gram-positive bacterium Staphylococcus aureus was evaluated using the colony-counting method. Film biodegradability was also visually assessed following soil burial for 40 days.Results: FTIR analysis showed a decrease in the intensity of the hydroxyl-associated absorption band at 3291 cm⁻¹ following HNT incorporation, suggesting possible hydrogen-bonding interactions between the hydroxyl groups of FM and the HNT surfaces. Thermal stability increased with increasing HNT content, with the 5% HNT-containing film exhibiting the highest thermal stability among the formulations investigated. EDX mapping showed an increase in the relative density of Si and Al signals with increasing HNT content, with the highest signal density observed in the film containing 5% HNT. Moisture absorption significantly decreased as the HNT content increased from 3% to 5%; among the formulations investigated, the 5% HNT-containing film exhibited the lowest moisture absorption (54.8%). WVP showed a similar decreasing trend, decreasing from 11.5 for the control film to 5.9 for the film containing 5% HNT. Increasing HNT content also improved the tensile strength of the FM films, with the 5% HNT-containing film reaching a tensile strength of 69.31 MPa. HNT incorporation altered the color characteristics of the films, as indicated by increased lightness (L*) and whiteness and decreased yellowness (b*). The antibacterial activity of the films also increased markedly following HNT incorporation. After 40 days of soil burial, the pure FM film exhibited faster apparent degradation than the HNT-containing films, while increasing HNT content delayed the apparent degradation process; the 5% HNT-containing film exhibited the slowest apparent degradation among the formulations investigated.Conclusion: Overall, the incorporation of HNTs as a reinforcing agent improved several functional and physicochemical properties of FM-based edible films. Among the formulations investigated, the film containing 5% HNT exhibited the highest thermal stability and lowest moisture absorption, together with improved tensile strength and antibacterial activity. These findings suggest that HNT-reinforced FM films, particularly those containing 5% HNT, have potential for use in the development of biodegradable edible food-packaging materials.
