Magazine covers
Volume 41, Issue 1 , February 2026
Editorial
Volume 41, Issue 1 , February 2026
Research Paper
Composite wood products
Jafar Ebrahimpour Kasmani; Ahmad Samariha; Alireza Khakifirooz
Abstract
Background and objectives: Considering the increasing attention to composites in various industries, the investigation and improvement of the mechanical and thermal properties of these materials have become particularly important. Given the environmental problems caused by the use of synthetic materials, ...
Read More
Background and objectives: Considering the increasing attention to composites in various industries, the investigation and improvement of the mechanical and thermal properties of these materials have become particularly important. Given the environmental problems caused by the use of synthetic materials, the use of natural and renewable materials such as spruce wood flour in combination with a polymer such as recycled polyethylene can be an effective solution for producing sustainable and environmentally friendly materials. This research aims to investigate the effect of mixing temperature on the mechanical and thermal properties of the composite made from spruce wood flour and recycled polyethylene. Temperature, as one of the key parameters in the composite production process, can have a significant impact on the physical, mechanical, and thermal properties. In this regard, investigating the effect of temperature on their mechanical and thermal behavior of this composite can help develop new products and improve their performance in various industries.Methodology: The use of wood flour as a natural and renewable material, along with recycled polyethylene, can contribute to the development of green and sustainable products. For this purpose, polyethylene (at a constant level of 50%), spruce wood flour (at a constant level of 50%), injection molding temperature (150, 170, and 190 degrees Celsius), and maleic anhydride grafted polypropylene (at a constant level of 3%) were mixed together using a twin-screw extruder. In this study, standard test specimens were made using the injection molding method. Mechanical properties including tensile and flexural strength, tensile and flexural modulus, as well as notched impact resistance were measured and evaluated. In addition, the thermal and flammability properties of the samples were also investigated.Results: The results showed that increasing the press temperature from 150 to 190 degrees Celsius significantly increased the tensile and flexural strength and modulus of the samples. Specifically, the notched impact resistance decreased by 8, 9.3, 7.5, 4.6, and 3.0 percent, respectively. These changes indicate the effect of temperature on the mechanical behavior and ability of this composite to withstand various loads. In addition, with increasing injection temperature, the thermal stability did not change much, and the amount of residual ash was 10.96, 10.96, 11.92, and 0.56 percent, respectively. These results indicate that even with temperature changes, the thermal stability of the composite is not significantly affected, and the amount of residual ash remains constant.Conclusion: The results of this research show that the mixing temperature directly affects the mechanical and thermal properties of the composite made from spruce wood flour and recycled polyethylene. Increasing the temperature can help improve the final performance of these types of composites in various applications, including packaging and the automotive industry. Choosing the right temperature and material composition can lead to the development of products with desirable characteristics and high performance. Overall, this research emphasizes the importance of temperature in the design and optimization of composites and can be used as a scientific basis for the development of new and sustainable materials in the future. Future studies could include a more detailed evaluation of the effects of temperature on other physical and chemical properties of this composite to gain a better understanding of their behavior under different conditions.
Research Paper
Management and Economics wood
Saeed Hosseininasr; Ajang Tajdini; Shademan Pourmousa
Abstract
Background and Objectives: Service quality is commonly defined as the difference between a customer's expectations before receiving a service and their perceptions of the service received. In wooden furniture companies; the quality of sales services enhances customer satisfaction and helps foster long-term ...
Read More
Background and Objectives: Service quality is commonly defined as the difference between a customer's expectations before receiving a service and their perceptions of the service received. In wooden furniture companies; the quality of sales services enhances customer satisfaction and helps foster long-term relationships. Accordingly, this study aimed to measure the quality of sales services provided by home wooden furniture companies by analyzing the gap between customers’ expectations and perceptions.Methodology: Customer satisfaction with service quality was measured across five dimensions: reliability, responsiveness, assurance, empathy, and tangibles. The main data collection tool was a modified SERVQUAL questionnaire, adapted to the context of wooden furniture sales services based on previous studies and research conditions. The research questionnaire was presented in three sections. The first section related to the demographic characteristics of the respondents. The second section of the questionnaire included 22 questions about the desired status (expectations) of customers regarding the quality of sales services, and the third section included the same number of questions about the current status (perceptions) of the respondents. The questions were scored using a five-point Likert scale. To examine the questionnaire’s validity and reliability, content validity methods and Cronbach’s alpha coefficient were employed. The statistical population of this study consisted of all customers visiting retail stores selling wooden home furniture in the city of Tehran. As the population was effectively infinite, a sample size of 386 respondents was determined. In this research, descriptive statistics—including frequency distribution, mean, and standard deviation—were used to describe the study variables. For hypothesis testing, the Wilcoxon test was used, and to rank the service quality dimensions from the customers’ perspective, the Friedman test was employed using SPSS software.Results: The results indicated that in home wooden furniture companies, customer expectations exceeded their perceptions in the all five dimensions of the SERVQUAL scale. The examination of the mean expectations and perceptions for each dimension of the SERVQUAL scale indicates a large gap in the sales services provided; such that the largest gap between customers’ perceptions and expectations in home wooden furniture companies relates to the responsiveness dimension (-1.27), and the smallest gap belongs to reliability (-1.13). The results of the Wilcoxon test for sales service quality and each of its dimensions showed that the gap between customers’ expectations and perceptions in home wooden furniture companies is significant at the 99% confidence level. It should be noted that this gap is negative, meaning that individuals’ expectations exceed their perceptions. The results of the Friedman test, regarding the prioritization of gaps across the dimensions from respondents’ viewpoints showed that empathy received the highest rank and physical factors the lowest. A lower mean rank indicated a larger gap between perceptions and expectations.Conclusion: In purchasing a variety of wooden furniture products, customers’ perceptions of the physical appearance of the purchased furniture, the neatness of sales and service staff and their methods of communication with customers, and the modernity and proper arrangement of company facilities in accordance with the type of services offered all fell short of their expectations. In the reliability dimension, the smallest gap between customer expectations and perceptions was found in the quality of sales services. In the direct showrooms of wooden furniture manufacturers, the ability to communicate with customers, sensitivity to customer needs, and the staff’s competencies to provide services affect customer satisfaction. Today, increased competition in the export market for diverse wooden furniture products has prompted many companies to consider service quality- including sales services- as a strategic tool in their operations.
Research Paper
Physics and Mechanical Wood
Hossein Babayi shahverdi; ّFarshid Faraji; Laya Jamali Rad; SeyyedMajid Zabihzadeh
Abstract
Background and Objective: Laminated Veneer Lumber (LVL) is one of the most important engineered wood products, offering efficient utilization of fast-growing species such as poplar. Despite its advantages, LVL suffers from dimensional instability and limited durability under moisture exposure, which ...
Read More
Background and Objective: Laminated Veneer Lumber (LVL) is one of the most important engineered wood products, offering efficient utilization of fast-growing species such as poplar. Despite its advantages, LVL suffers from dimensional instability and limited durability under moisture exposure, which restricts its wider applications. In recent years, various fillers have been added to phenol-formaldehyde (PF) resins to enhance physical and mechanical properties of LVL. Waste tire powder, owing to its hydrophobic and polymeric nature, has emerged as a promising alternative to traditional fillers such as wheat flour. Recycling waste tires not only contributes to sustainable waste management but also offers a low-cost resource for wood composites. This study aimed to investigate the effect of particle size (40, 60, 80 mesh) and content (10, 20, 30%) of waste tire powder on the mechanical and physical properties of poplar LVL.Materials and Methods: Two 12-year-old poplar (Populous nigra) trees were harvested and peeled into 2.2 mm veneers, which were conditioned to about 5% moisture content. Phenol-formaldehyde resin dissolved in methanol without additives was used as the adhesive. Waste tire powder obtained from a recycling plant was sieved into three particle sizes (40, 60, 80 mesh). It was incorporated into the PF resin at 10, 20, and 30% based on the dry weight of resin. For comparison, control samples were prepared using 20% wheat flour as filler. In total, 27 experimental LVL panels (9 treatments × 3 replications) plus 3 control panels were produced. The panels were hot-pressed at 180°C under a pressure of 30 kg/cm² for 8 minutes. Mechanical properties including modulus of rupture (MOR) and modulus of elasticity (MOE) were evaluated according to EN 310, screw and nail withdrawal resistance according to ASTM D 1037, and physical properties including water absorption and thickness swelling (24 h immersion) according to EN 317. A completely randomized design was applied, and data were analyzed using analysis of variance (ANOVA). Multiple comparisons of means were performed using Turkey’s test at 95% and 99% confidence levels.Results: The results indicated that both particle size and content of waste tire powder significantly affected the physical and mechanical performance of poplar LVL. MOR decreased in all treatments compared with the control; however, the reduction was less pronounced at 20% and 30% content, which showed no significant difference from each other. MOE followed a similar trend, with finer particles (60 and 80 mesh) outperforming coarser particles (40 mesh). Screw and nail withdrawal resistance were highly influenced by the interaction of both factors. The combination of 20% tire powder with 80-mesh particles resulted in the highest screw holding strength (an improvement over the control), while the weakest performance was observed at 10% content and 40 mesh. Regarding physical properties, waste tire powder showed a remarkable positive effect. Treatments with higher contents and finer particles exhibited significant reductions in water absorption and thickness swelling compared with the control. Specifically, panels with 30% and 80 mesh achieved the lowest water absorption, while 20% with 60 mesh provided the best dimensional stability with over 40% reduction in thickness swelling. These findings suggest that finer tire particles at moderate-to-high contents enhance resin distribution, reduce voids, and improve interfacial bonding, thereby increasing resistance to moisture.Conclusion: Based on the findings, the use of waste tire powder in phenol formaldehyde resin can be proposed as a sustainable approach in the production of Populous nigra LVL. Although mechanical properties such as flexural strength were slightly reduced, the modulus of elasticity and joint strength were maintained under optimal conditions. On the other hand, the improvement of physical properties such as reduced water absorption and thickness swelling is likely the result of the positive interaction between tire powder and the hydrophobic nature of phenol formaldehyde adhesive. Therefore, the use of tire powder in adhesive formulation can be an effective approach to improve sustainability and develop a circular economy in the engineered wood industry, while contributing to the recycling of waste tires.
Research Paper
Chemical conversion
Seyedeh Motahareh Mohseni Shektaii; Seyed Majid Zabihzadeh; Maryam Ghorbani Kokandeh; Ghasem Asadpur
Abstract
Background and objectives: Pectin is a multifunctional polysaccharide widely used in the food, pharmaceutical, and packaging industries. Owing to its valuable functional properties, global demand for pectin exceeds 30,000 tons per year, with an annual market growth of approximately 4–5%. Lime peel ...
Read More
Background and objectives: Pectin is a multifunctional polysaccharide widely used in the food, pharmaceutical, and packaging industries. Owing to its valuable functional properties, global demand for pectin exceeds 30,000 tons per year, with an annual market growth of approximately 4–5%. Lime peel (Citrus aurantifolia), particularly its inner white layer (albedo), is rich in pectin and represents an economical and sustainable raw material for pectin production. Utilizing this agro-industrial by-product not only provides added economic value but also contributes to reducing the environmental impacts associated with waste disposal. Conventional pectin extraction methods rely on mineral acids, which, despite ensuring high extraction yields, are associated with elevated production costs and environmental concerns. In contrast, organic acids such as citric acid function as green solvents, providing desirable yields while minimizing adverse environmental effects. Accordingly, the present study aimed to optimize acid extraction of pectin from lime peel to achieve maximum yield and desirable quality characteristics, including high purity and adjustable degree of methoxylation.Methodology: Lime albedo was separated from fresh fruit, washed, chopped, and dried at 50 °C to a constant weight, then ground and passed through a 20-mesh sieve. For acid extraction, 10 g of albedo powder was mixed with an aqueous citric acid solution at a fixed liquid-to-solid ratio of 30:1 (v/w) under three pH levels (1, 2, and 3). The resulting suspension was subjected to extraction at temperatures of 65, 80, and 95 °C and for extraction times of 30, 60, and 90 minutes. After centrifugation, pectin was precipitated using absolute ethanol, washed with 96% ethanol, dried at 40 °C, and subsequently powdered. A Box–Behnken experimental design was employed with three independent variables (temperature, time, and pH) at three levels, comprising 15 experimental runs. Extraction yield was calculated gravimetrically; galacturonic acid content (GalA) was determined by a colorimetric method using the m-hydroxydiphenyl reagent with absorbance measured at 520 nm; and degree of esterification (DE) was quantified via a two-step titration method (neutralization and saponification). Data were fitted to a second-order polynomial model using Design Expert version 13, and the optimal model was selected based on analysis of variance (ANOVA), coefficient of determination (R²), adjusted R², and lack-of-fit tests.Results: The pectin extraction yield was significantly influenced by the processing conditions and varied between 8.21% and 53.8%. The highest yield was obtained at 80 °C, 90 minutes, and pH 1, whereas the lowest yield occurred at pH 3 under lower temperature conditions. The degree of esterification (DE) also showed a clear dependency on extraction parameters; the highest DE value (61.11%) was achieved under milder conditions (80 °C, 30 minutes, pH 3), indicating the production of high-methoxyl pectin. In contrast, more severe extraction conditions—such as pH 1 combined with prolonged extraction time—led to a marked reduction in DE to approximately 9.13%, resulting in low-methoxyl pectin. Galacturonic acid content was similarly affected by extraction severity; the highest purity (87.83%) was observed at pH 3, 30 minutes, and 80 °C, while significantly lower purity values were recorded under highly acidic conditions. The regression models developed for yield, DE, and GalA exhibited excellent statistical performance, with coefficients of determination (R²) exceeding 0.98, confirming the high accuracy and predictive capability of the models in describing the extraction system.Conclusion: The findings of this study confirm the effectiveness of citric acid as a green and environmentally friendly solvent for extracting pectin from lime peel. Under optimized conditions, pectin with high yield, high purity, and an adjustable degree of esterification was successfully obtained. The application of response surface methodology enabled precise modeling of the extraction process, and the close agreement between predicted and experimental values demonstrated the strong validity and reliability of the developed model.Given its high purity and tunable methoxyl content, the extracted pectin is suitable for a wide range of applications in the food, pharmaceutical, and bio-based packaging industries. Utilizing lime peel - an abundant by-product of the lime juice industry - as a raw material not only provides a valuable source for pectin production but also contributes to sustainable development, agricultural waste management, and the reduction of environmental impacts. This approach offers an effective strategy for converting plant-based waste materials into value-added products within related industries.
Research Paper
Wood Modification and Wood Preservation
Fatemeh Hasanzadeh Fard; Mehdi Jonoobi; peyman ahmadi
Abstract
Background and Objectives: Surface coating plays a crucial role in enhancing the durability, dimensional stability, and environmental resistance of wood. In this context, water-based polyurethane (WBPU) coatings have attracted increasing attention as sustainable alternatives to solvent-based systems ...
Read More
Background and Objectives: Surface coating plays a crucial role in enhancing the durability, dimensional stability, and environmental resistance of wood. In this context, water-based polyurethane (WBPU) coatings have attracted increasing attention as sustainable alternatives to solvent-based systems due to their lower VOC emissions and satisfactory mechanical and aesthetic performance. However, the functional efficiency of these coatings is strongly influenced by the application method and, in particular, by coating thickness. Despite its significance, systematic investigations on the effect of coating thickness especially when applied using advanced techniques such as spin coating under aging conditions remain limited. The present study introduces spin coating as a novel approach for wood finishing and evaluates the influence of different WBPU coating thicknesses on the surface and mechanical performance of beech wood (Fagus orientalis). The main objective is to determine an optimal coating thickness that provides a balanced performance in terms of hydrophobicity, adhesion, visual stability, and resistance to accelerated aging.Materials and Methods: Beech wood specimens were coated using a commercial acrylic-based WBPU applied via spin coating at four different application levels (3, 6, 9, and 12 coating cycles). Each cycle involved a fixed spin speed of 2000 rpm and a duration of 30 seconds. The thickness of the resulting films was measured through stereomicroscopy and image analysis. A comprehensive set of physical and surface tests was conducted both before and after artificial aging, including water absorption (ASTM D5795), surface roughness (SJ-201P profilometer), dynamic water contact angle (ASTM D5946), color variation (CIE-Lab, ΔE), tensile pull-off adhesion strength (ASTM D4541), and scratch adhesion (ASTM D3359). The accelerated aging process simulated environmental degradation through a humidity-temperature chamber, allowing for the assessment of coating durability over time. In addition, multi-objective optimization using Minitab’s Response Optimizer was employed to identify the film thickness that offered the best overall functional performance.Results: Results showed a nearly linear increase in film thickness from 75 µm (3 cycles) to 286 µm (12 cycles). Thicker coatings demonstrated lower water absorption and higher contact angles exceeding 90° indicating enhanced hydrophobic properties. After aging, thicker films also showed reduced color change (ΔE), with the 9-cycle treatment presenting the best balance of aesthetic and mechanical attributes. This treatment exhibited the highest tensile adhesion strength (2.99 MPa) before aging, and it retained significant adhesion after aging, suggesting strong interfacial bonding and structural integrity. In contrast, the 12-cycle treatment, while superior in terms of water resistance, showed a noticeable drop in adhesion, potentially due to internal stresses or micro-cracks caused by excessive film thickness. Scratch adhesion remained high (5B) in all treatments before aging, but minor deterioration was observed in thicker coatings after aging.The multi-criteria optimization revealed that a film thickness of approximately 206 µm corresponding closely to the 9-cycle treatment provided the highest composite desirability score (0.94) across all evaluated parameters. This result confirms that increasing thickness beyond an optimal range does not necessarily improve overall performance and may instead compromise adhesion or visual consistency due to mechanical stress accumulation during drying or exposure.Conclusion: In conclusion, spin coating is demonstrated to be an effective and innovative method for applying uniform, controllable WBPU coatings on wooden substrates. This study confirms that coating thickness is a pivotal factor influencing water resistance, surface quality, color stability, and adhesion. An intermediate thickness (210 µm) offers the most favorable combination of performance attributes, making it suitable for practical use in interior wood products, furniture, and protective applications. The research supports the integration of spin coating into sustainable wood finishing systems and provides a foundation for further exploration of advanced coating technologies in the wood science field.
Research Paper
Wood Modification and Wood Preservation
Masood Kafi; Rahmat Madandoust; Heydar Dashti Nasserabadi; Javad Torkaman
Abstract
Background and Objectives: Cellulosic fibers particularly plant-based fibers have gained increasing importance as sustainable alternatives to synthetic materials in composite, automotive, and construction industries due to their renewability, low production cost, light weight, and favorable mechanical ...
Read More
Background and Objectives: Cellulosic fibers particularly plant-based fibers have gained increasing importance as sustainable alternatives to synthetic materials in composite, automotive, and construction industries due to their renewability, low production cost, light weight, and favorable mechanical properties. Bamboo, characterized by its rapid growth, orderly fibrous structure, high strength, and biodegradability, represents a prominent resource for bio‑composites. The bamboo cell wall is primarily composed of cellulose, hemicellulose, and lignin, with cellulose microfibrils embedded in a flexible hemicellulosic matrix within the primary wall. However, the intrinsic hydrophilicity and weak interfacial bonding of bamboo fibers pose major challenges in composite applications, necessitating chemical and thermal modification. This study aims to evaluate the effectiveness of boric acid (H3BO3), sodium hydroxide (NaOH), and boiling-water treatments on the physical and structural properties of bamboo. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to characterize the modifications.
Materials and Methods: Bamboo samples (Phyllostachys vivax) were air-dried and cut into 3 × 3 cm specimens. The samples were divided into four groups: untreated control, boiling-water treatment (6 h immersion), boric acid treatment (1 h immersion in 6% solution), and sodium hydroxide treatment (10 h immersion in 1% solution). Prior to treatment, samples were oven-dried at (103 ± 2°C), and mass, volume, and density were recorded. Surface and thickness swelling were quantified using stereo-microscope images analyzed in Image J. Water absorption was measured at 24, 48, and 72 hours, and subsequently at weekly intervals up to four weeks. Molecular structural changes were assessed using FTIR, and microstructural variations were examined through SEM imaging.
Results: Physical assessments revealed that control samples exhibited moderate reductions in mass (8.38%) and volume (3.91%) after oven-drying. Samples treated with boiling water and NaOH showed increased density due to substantial mass and volume loss associated with extractive degradation. In contrast, boric acid treatment resulted in lower mass loss and a notable 6.80% increase in volume, leading to reduced density. After 28 days of immersion, all chemical and thermal treatments increased water absorption. Boric acid treatment exhibited the highest water uptake due to the hygroscopic nature of boron, whereas NaOH treatment showed increased porosity resulting from lignin and hemicellulose removal. Regarding swelling, boiling-water and NaOH treatments increased swelling, while boric acid treatment effectively reduced it through the formation of cross-linking bonds. FTIR analysis indicated that NaOH treatment degraded hemicellulose and lignin. In the boric acid spectrum, a reduction in hydroxyl peak intensity and the emergence of new B–O cross-linking bands were observed. SEM images confirmed a compact structure in the control sample, slight porosity in the boiling-water treatment, boron deposition in the boric acid treatment, and pronounced porosity in the NaOH treatment. These observations clearly demonstrated the role of boric acid in producing high water absorption but low swelling, and the role of NaOH in generating high swelling yet improved fiber–matrix adhesion.
Conclusion: This study demonstrates that chemical and thermal treatments effectively alter the bamboo cell-wall structure. Boric acid treatment, despite increasing water absorption, significantly reduces swelling and provides desirable dimensional stability for structural applications of bamboo—particularly as reinforcement in concrete. Conversely, NaOH treatment increases swelling and porosity but enhances fiber–matrix adhesion in composites. These findings, supported by spectral and microscopic analyses, address the challenges associated with the hydrophilicity of plant fibers and highlight the strong potential of bamboo in bio‑composite applications. Future research should focus on optimizing combined treatments and evaluating the industrial performance of treated bamboo products.
)