Iranian Journal of Wood and Paper Science Research

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Volumes of the Iranian Journal of Wood and Paper Science Research

Volume 41, Issue 1 , February 2026

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Editorial

Volume 41 Issue 1 spring - Serial Number 94

Volume 41, Issue 1 , February 2026

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Research Paper Composite wood products

Investigation of the Effect of Mixing Temperature on the Mechanical and Thermal Properties of Spruce Wood Flour and Recycled Polyethylene Composites

Jafar Ebrahimpour Kasmani; Ahmad Samariha; Alireza Khakifirooz

Volume 41, Issue 1 , February 2026, Pages 1-14

https://doi.org/10.22092/ijwpr.2025.370499.1812

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

Identifying the gaps between customers' expectations and perceptions of sales service quality dimensions in wooden home furniture companies

Saeed Hosseininasr; Ajang Tajdini; Shademan Pourmousa

Volume 41, Issue 1 , February 2026, Pages 15-31

https://doi.org/10.22092/ijwpr.2025.370770.1815

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

Effect of using waste tire powder as a filler of alcohol soluble PF resin on physical and mechanical properties of Populous nigra LVL

Hossein Babayi shahverdi; ّFarshid Faraji; Laya Jamali Rad; SeyyedMajid Zabihzadeh

Volume 41, Issue 1 , February 2026, Pages 32-45

https://doi.org/10.22092/ijwpr.2025.370941.1816

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

Green Extraction of Pectin from Lime Peel: Modeling and Optimization Using Response Surface Methodology

Seyedeh Motahareh Mohseni Shektaii; Seyed Majid Zabihzadeh; Maryam Ghorbani Kokandeh; Ghasem Asadpur

Volume 41, Issue 1 , February 2026, Pages 46-68

https://doi.org/10.22092/ijwpr.2025.371455.1820

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

Evaluation of the Performance of Water-Based Polyurethane Coating Applied by Spin Coating at Different Thicknesses on Beech Wood under Accelerated Aging Conditions

Fatemeh Hasanzadeh Fard; Mehdi Jonoobi; peyman ahmadi

Volume 41, Issue 1 , February 2026, Pages 69-91

https://doi.org/10.22092/ijwpr.2026.371631.1822

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

Investigation of chemical and thermal modification of bamboo (Phyllostachys vivax) cell wall through spectroscopy (FTIR) and scanning electron microscopy (SEM)

Masood Kafi; Rahmat Madandoust; Heydar Dashti Nasserabadi; Javad Torkaman

Volume 41, Issue 1 , February 2026, Pages 92-111

https://doi.org/10.22092/ijwpr.2026.371327.1819

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.

Identify the Chemical Composition of Tobacco Stem Wood Extractives (Nicotiana tabacum L. 'Coker 347') by Gas Chromatography- Mass Spectrometry

Volume 29, SPRING 1 , May 2014, , Pages 66-57

https://doi.org/10.22092/ijwpr.2014.4907

Abstract

Tobacco (Nicotianan tabacum) and an old industrial plant in the north, Iran to supply tobacco leaf to produce significant amounts of stem tobacco cultivation and the annual production is in the north of the country. In this research stems of tobacco variety Coker 347 randomly Gilan district, city of ... Read More

Investigation on the possibility of oriented strand board (OSB) production from hornbeam wood

Volume 34, Issue 1 , April 2019, , Pages 140-156

https://doi.org/10.22092/ijwpr.2019.125254.1523

Abstract

DOR:98.1000/1735-0913.1398.34.140.66.1.9.1586 In this study, the possibility of three-layered oriented strand board production from hornbeam (Carpinus betulus L.) wood was evaluated. Two levels of press time (6 and 8 minutes) and three levels of press temperature (180˚C, 200˚C and 220˚C) were applied ... Read More

Dielectric properties of oil impregnated kraft and soda pulps

Volume 28, Summer 2 , June 2013, , Pages 329-340

https://doi.org/10.22092/ijwpr.2013.2937

Abstract

This research was carried out with the aim of determining dielectric properties of bagasse unbleached soda pulp, long fiber kraft pulp and a mixture of both (20% kraft + 80% bagasse soda).The hand-sheets with 60 g/m2 basis weight were made after adjusting the freeness of pulps at levels of 200 ± ... Read More

Morphological Characteristics and Chemical Composition of Grapevine Branches (Vitis vinifera spp.) Grown in Astara

Volume 30, WINTER 4 , December 2015, , Pages 525-537

https://doi.org/10.22092/ijwpr.2015.102670

Abstract

This study has been conducted to determine morphological characteristics of fibers and amount of chemical components of grapevine branches cultivated in Astara in province of Guilan. For this purpose the number of 53 branches, with same size and diameter, were cut from some grapevine and sent to laboratory ... Read More

Evaluation of the local dynamic modulus of elasticity in wooden tie by the stress wave method

Volume 39, Issue 2 , June 2024, , Pages 133-145

https://doi.org/10.22092/ijwpr.2023.361802.1751

Abstract

Background and objectives: From the limitations of detecting the amount of useful life remaining in the components of the structures in the conditions of use with acoustic methods is the impossibility of calculating the modulus of elasticity due to the impossibility of removing the part from the structure. ... Read More Background and objectives: From the limitations of detecting the amount of useful life remaining in the components of the structures in the conditions of use with acoustic methods is the impossibility of calculating the modulus of elasticity due to the impossibility of removing the part from the structure. Therefore, most of the classifications during use in the components of structures such as historical buildings are based on measuring the speed of sound. In this research, to calculate the local and global density with the method of pin penetration rate in wooden tie in order to calculate the amount of their remaining useful life by combining stress wave and free longitudinal vibration methods has been studied. There was no significant difference between the values of global sound velocity and global modulus of elasticity with the local results of these factors at the five tested points in each of the wooden tie.Methodology: The number of three saturated wooden tie from Iran Railway Company and with the dimensions of 15x25x260 cm, which are made of beech species (Fagus orientalis) and the density was measured by pin penetration method at 5 points of each wooden tie (50 cm distance between each point) and the average results of 5 points were compared with the results of ISO 13910 standard method. The stress wave test was carried out at the same 5 points of density determination by pin penetration rate method to determine the local modulus of elasticity and the results of each point were compared with the global modulus of elasticity of the beam. Longitudinal vibration test was also performed to calculate the damping factor values of the samples.Results: The results showed that there was no significant difference at the 95% level between the values calculated with both the ISO 13910 standard methods and the pin penetration rate method, and there was a favorable linear correlation between the results of the two methods. According to the results, there was no significant difference between the global sound speed of the beams and their local sound speed in any of the five measured points at the 95% level and there was a linear correlation between the values of the global sound speed and each of the five local points. There was no significant difference at the 95% level between the values of the global modulus of elasticity and the values of the local modulus of elasticity calculated in each of the five points. Also, there was a linear correlation between the values of the global modulus of elasticity and the results of the local modulus of elasticity in each of the five points. There was an exponential correlation between the values obtained from the global modulus of elasticity and the damping factor of each of the wooden tie.Conclusion: The equality of density according to the ISO 13910 standard method and the nail penetration method, as well as the equality of the modulus of elasticity calculated by the stress wave method and the free longitudinal vibration method, make it possible to obtain all the data required for calculations without removing the part from the structure. The remaining strength of wooden components should be provided according to EN338 standard.

Research Paper

Evaluation of Wood Physical, Biometry and Mechanical Properties of Juniperus excelsa (A Case Study in the Hezar-Masjed Mountains, Dargaz)

Majid Kiaei

Articles in Press, Accepted Manuscript, Available Online from 15 March 2026

https://doi.org/10.22092/ijwpr.2026.371818.1825

Abstract

Background and Objective: Physical, biometric, and mechanical properties of wood are important indicators for assessing the quality and potential industrial and ecological applications of different wood species. Juniperus excelsa, due to its slow growth and unique cellular structure, exhibits distinctive ... Read More Background and Objective: Physical, biometric, and mechanical properties of wood are important indicators for assessing the quality and potential industrial and ecological applications of different wood species. Juniperus excelsa, due to its slow growth and unique cellular structure, exhibits distinctive characteristics in terms of density and mechanical strength. However, limited information is available regarding the variation of these properties along radial and longitudinal axes of the tree stem. This study aimed to investigate and analyze the changes in physical, biometric, and mechanical properties of J. excelsa wood along radial and longitudinal axes, and to identify patterns of variation from pith to bark and from the base to the top of the stem.Materials and Methods: Three healthy J. excelsa trees were selected in the Hezar Masjed Mountains (Darghaz, Iran), and three stem sections were collected from each tree at breast height (1.3 m), 3 and 6m. From each stem section, three radial samples from pith to bark were prepared for measuring physical properties (air-dried density, basic density, and volumetric shrinkage), biometric properties (tracheid length, tracheid diameter, and cell wall thickness), and mechanical properties (bending strength and modulus of elasticity). Data were analyzed using two-way ANOVA to examine the effects of radial and longitudinal positions on wood properties.Results: The mean air-dried density and basic density, and volumetric shrinkage were 0.442 and 0.413 g/cm³, and volumetric swelling was 10.80%, respectively. Tracheid length, tracheid diameter, and cell wall thickness were 1.572 mm, 31.41 µm, and 5.58 µm, respectively, while bending strength and modulus of elasticity were 41.66 MPa and 4.47 GPa. The study demonstrates that physical, biometric, and mechanical properties of J. excelsa wood are strongly influenced by the sampling position along radial and longitudinal axes, with identifiable patterns from pith to bark and from the base to the top of the tree.Conclusion: These findings provide valuable information for industrial applications of J. excelsa wood and sustainable management of its forest resources.Keywords: Juniperus excelsa,, wood density, volumetric swelling, Fiber dimension, modulus of rupture, modulus of elasticity, Background and Objective: Physical, biometric, and mechanical properties of wood are important indicators for assessing the quality and potential industrial and ecological applications of different wood species. Juniperus excelsa, due to its slow growth and unique cellular structure, exhibits distinctive characteristics in terms of density and mechanical strength. However, limited information is available regarding the variation of these properties along radial and longitudinal axes of the tree stem. This study aimed to investigate and analyze the changes in physical, biometric, and mechanical properties of J. excelsa wood along radial and longitudinal axes, and to identify patterns of variation from pith to bark and from the base to the top of the stem.Materials and Methods: Three healthy J. excelsa trees were selected in the Hezar Masjed Mountains (Darghaz, Iran), and three stem sections were collected from each tree at breast height (1.3 m), 3 and 6m. From each stem section, three radial samples from pith to bark were prepared for measuring physical properties (air-dried density, basic density, and volumetric shrinkage), biometric properties (tracheid length, tracheid diameter, and cell wall thickness), and mechanical properties (bending strength and modulus of elasticity). Data were analyzed using two-way ANOVA to examine the effects of radial and longitudinal positions on wood properties.Results: The mean air-dried density and basic density, and volumetric shrinkage were 0.442 and 0.413 g/cm³, and volumetric swelling was 10.80%, respectively. Tracheid length, tracheid diameter, and cell wall thickness were 1.572 mm, 31.41 µm, and 5.58 µm, respectively, while bending strength and modulus of elasticity were 41.66 MPa and 4.47 GPa. The study demonstrates that physical, biometric, and mechanical properties of J. excelsa wood are strongly influenced by the sampling position along radial and longitudinal axes, with identifiable patterns from pith to bark and from the base to the top of the tree.Conclusion: These findings provide valuable information for industrial applications of J. excelsa wood and sustainable management of its forest resources.Keywords: Juniperus excelsa, wood density, volumetric swelling, Fiber dimension, modulus of rupture, modulus of elasticity,

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Research Paper

Structure–property relationships of pectin reinforced with cellulose nanofibrils for sustainable bionanocomposite films

Seyedeh Motahareh Mohseni Shektai; Maryam Ghorbani Kokandeh; Ghasem Asadpur

Articles in Press, Accepted Manuscript, Available Online from 04 May 2026

https://doi.org/10.22092/ijwpr.2026.371750.1823

Abstract

AbstractBackground and Objective: The extensive use of petroleum-based polymers in the packaging industry, due to their non-biodegradable nature, has led to the accumulation of persistent waste, contamination of soil and surface waters, and ultimately the degradation of ecosystems. In this context, biopolymers ... Read More AbstractBackground and Objective: The extensive use of petroleum-based polymers in the packaging industry, due to their non-biodegradable nature, has led to the accumulation of persistent waste, contamination of soil and surface waters, and ultimately the degradation of ecosystems. In this context, biopolymers - particularly pectin extracted from citrus peels as an agricultural by-product - have emerged as suitable alternatives to conventional synthetic polymers. The extraction of pectin using organic acids such as citric acid represents a green and sustainable approach, owing to its safety, environmental compatibility, and ability to produce materials of appropriate quality. However, films made from neat pectin generally exhibit limitations in mechanical strength and barrier performance. Cellulose nanofibrils, due to their high elastic modulus, favorable tensile strength, and biodegradability, can be effectively employed as reinforcing agents within pectin matrices. The aim of this study was to fabricate and characterize pectin/CNF bionanocomposite films with enhanced properties for biodegradable packaging applications.Methodology: Pectin with a degree of esterification of 61.63% was extracted from lemon peel using citric acid, and cellulose nanofibrils (CNF) were supplied by NanoNovin Polymer Co. Films were prepared using the solution casting method. Briefly, pectin was dissolved in distilled water at 70 °C, glycerol was then added as a plasticizer, and the pH of the solution was adjusted to 4. Simultaneously, CNF was dispersed in distilled water at concentrations of 1, 3, and 5% (w/w) and subjected to ultrasonication for 30 min to ensure uniform dispersion. The CNF suspension was subsequently added to the pectin solution, and the mixture was homogenized for 25 min. After degassing in a vacuum oven, the film-forming solutions were cast into Petri dishes and dried for 48 h in a desiccator containing a saturated magnesium nitrate solution (52.8% relative humidity at 25 °C). The tensile properties, optical properties, thickness, water vapor permeability, and moisture absorption of the films were evaluated. Neat pectin films and films containing 5% CNF were selected for Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses. Statistical analysis of the data was performed using SPSS software.Results: The results demonstrated that the incorporation of cellulose nanofibrils (CNF) had a significant effect on the properties of pectin-based films. The Young’s modulus increased from 3.12 MPa for the neat pectin film to 8.08 MPa for the film containing 5% CNF. Likewise, the tensile strength increased from 1.42 to 2.60 MPa, and the tensile energy absorption increased from 12.94 to 22.43 J, indicating a simultaneous improvement in stiffness, strength, and toughness of the system. The water vapor permeability decreased by approximately 51% upon the addition of 5% CNF, from 4.54 × 10⁻¹¹ to 2.22 × 10⁻¹¹ g/m·s·Pa, demonstrating a substantial enhancement in barrier performance comparable to that of cellophane. In addition, the moisture absorption of the films decreased to 25.35% at a CNF content of 5%. In contrast, increasing the CNF content resulted in a reduction in film transparency from 98.26% to 80.09%. FTIR analysis confirmed the formation of strong hydrogen bonds between CNF and the pectin matrix. XRD patterns revealed an approximately 73% increase in diffraction intensity, indicating an improvement in the degree of crystallinity. Furthermore, SEM micrographs confirmed the relatively uniform dispersion of cellulose nanofibrils and good interfacial compatibility between CNF and the pectin matrix.Conclusion: The findings of this study demonstrated that pectin/cellulose nanofibril bionanocomposite films provide a favorable combination of mechanical and barrier properties. The enhanced performance of this system can be attributed to the formation of strong hydrogen bonds between the pectin matrix and CNF, an increased degree of crystallinity, and the development of a three-dimensional reinforcing network. Accordingly, pectin/cellulose nanofibril films represent a promising biodegradable alternative to conventional plastic packaging materials and can contribute effectively to reducing the environmental impacts of packaging waste within the framework of the circular economy and sustainable development.

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