Iranian Journal of Wood and Paper Science Research

Editorial

Volume 41 Issue 2 summer - Serial Number 95

Volume 41, Issue 2 , June 2026

Abstract

Editorial

Research Paper Pulp and paper

Identification and comparative of organic chemical components in fluting and kraft liner papers using gas chromatography–mass spectrometry (GC-MS)

Ramin Vaysi

Volume 41, Issue 2 , June 2026, Pages 113-125

https://doi.org/10.22092/ijwpr.2026.371055.1818

Abstract

Background and aim: Fluting paper and Kraft liner paper are among the most important grades of paper produced in the pulp and paper industry, particularly for the manufacture of corrugated board. Fluting paper is typically made from a mixture of hardwood fibers using the Neutral Sulfite Semi-Chemical ... Read More Background and aim: Fluting paper and Kraft liner paper are among the most important grades of paper produced in the pulp and paper industry, particularly for the manufacture of corrugated board. Fluting paper is typically made from a mixture of hardwood fibers using the Neutral Sulfite Semi-Chemical (NSSC) pulping process adding some softwood pulp, while kraft liner paper is produced from similar raw materials through the Kraft pulping process also adding some softwood pulp. However, due to limitations in wood supply and competition for primary raw materials, a significant portion pulp for these papers in Iran is recycled fibers, such as OCC and converting mill rejects. This study employs Gas Chromatography-Mass Spectrometry (GC-MS) to precisely identify and compare the organic compounds present in corrugated paper and kraft liner paper. The primary aim of this research is to evaluate the impact of various chemical constituents on the structural and functional properties of these two types of papers. Additionally, the study attempt to find these chemical roles in optimizing production processes and improving the overall quality of the final product within the paper manufacturing industry.Materials and Methods: In this study, fluting paper samples were collected from the production line of machine No. 2 at Mazandaran Wood and Paper Mill, and kraft liner paper samples were obtained from Chooka paper mill in Gilan. Initially, the ash content and extractable substances in the samples were quantified according to TAPPI standards. The extractable substances were then separated from the paper pulp using acetone as a solvent. The remaining extracts were transferred to glass vials, to which BSTFA (N, O-Bis(trimethylsilyl)trifluoroacetamide) reagent was added. The samples were heated in a water bath at 70°C for one hour before being injected into the GC-MS system for analysis. Compound identification was performed using retention time chromatograms, the Quats index and Adams table.Results: GC-MS analysis of the fluting paper identified a total of 76 compounds, with the most abundant being benzaldehyde (20.44%), benzene methanol (5.32%), 9-octadecenoic acid (5.16%), bis(2-ethylhexyl) phthalate (4.33%), gamma-sitosterol (1.34%), and beta-sitosterol (1.01%). These compounds primarily consisted of aromatic hydrocarbons and natural fatty acids. In contrast, GC-MS analysis of kraft liner paper identified 28 compounds, with the major components being bis(2-ethylhexyl) phthalate (28.21%), hexadecanoic acid (24.25%), 9-octadecenoic acid (11.67%), octadecanoic acid (10.45%), hexadecane (7.12%), pimaric acid (2.06%), 1,2-benzenedicarboxylic acid (1.17%), squalene (1.40%), and syringyl aldehyde (0.31%). These substances were predominantly industrial plasticizers and fatty acids, which play an important role in the composition and functional properties of Kraft liner paper. The GC-MS analysis of fluting paper also revealed the presence of compounds such as p-xylene, benzaldehyde, dibenzyl, formylmorpholine, and benzyl alcohol, which were not detected in kraft liner paper. Additionally, light alkanes (such as decane, dodecane, and nonadecane) and phytosterols, specifically beta- and gamma-sitosterol, were uniquely present in fluting paper, supporting the hypothesis of differences in fiber sources or the use of specific additives in fluting paper production. In contrast, phenolic and aromatic compounds detected in fluting paper may be derived from adhesives, inks, or residual chemicals in the manufacturing process. For kraft liner paper, compounds such as abietic acid, pimeric acid, and isocunabic acid were identified, which were absent in fluting paper. Additionally, long-chain hydrocarbons such as tetracosane and squalene were found specifically in this sample, indicating the potential use of softwood fibers or non-fibrous additives like rosin.Conclusion: The comparison of GC-MS profiles between fluting paper and kraft liner paper revealed that both grades of paper share common chemical constituents, including long-chain alkanes and natural fatty acids. Furthermore, bis(2-ethylhexyl) phthalate, an industrial plasticizer, plays a significant role in improving the mechanical properties of both paper types. The observed differences in specific compounds, such as the presence of aromatic compounds and light alkanes in fluting paper and long-chain hydrocarbons and resins in kraft liner paper, suggest variations in fiber sources, pulping processes, and the use of additives. These differences could provide valuable insights for optimizing paper formulations and enhancing the quality of paper products.

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Research Paper Physics and anatomy

Anatomical, Physical, and Chemical Properties of Stem and Branch Wood of Populus nigra

Majid Kiaei; sadegh karimi

Volume 41, Issue 2 , June 2026, Pages 126-139

https://doi.org/10.22092/ijwpr.2026.371526.1821

Abstract

Background and Objectives: Poplar (Populus nigra) is widely used in afforestation programs due to its rapid growth and easy availability, making it an important source of raw material for wood-based industries. This study aimed to evaluate and compare the physical, anatomical, and chemical properties ... Read More Background and Objectives: Poplar (Populus nigra) is widely used in afforestation programs due to its rapid growth and easy availability, making it an important source of raw material for wood-based industries. This study aimed to evaluate and compare the physical, anatomical, and chemical properties of stem and branch wood of this species, as well as to examine their variation along the branch axis.Materials and methods: ،Three trees were selected and from each tree, one sample at breast height of the stem and three samples from three branches at different elevation of the tree were taken. Fiber length, fiber diameter, cell-wall thickness, lumen diameter, biometric indices, vessel diameter, wood density, lignin, cellulose, hot-water extractives, and alcohol–acetone extractives were measured using appropriate preparation and test methodsResults: The results showed that all measured properties differed significantly between stem and branch wood. Stem fibers are longer, diameter, and wall thickness are wider, indicating a higher level of anatomical maturity. In contrast, branch wood with its smaller fibers exhibited higher slenderness ratio and Runkel ratio. Branch wood also showed fairly higher density, while vessel diameter was larger in the stem and displayed a decreasing trend from the base to the tip of the branch. Chemically, cellulose, lignin, and extractive contents were all higher in stem wood, whereas these components declined gradually along the branch.Conclusion: Overall, the findings indicate that stem wood, due to its structural maturity and higher lignocellulosic content, is more suitable for wood and paper applications. However, branch wood owing to its higher density, acceptable papermaking indices, and adequate fiber characteristics can serve as an economical and accessible supplementary source for pulp production. These results highlight the potential role of branches in improving raw-material utilization and promoting sustainable wood-resource management

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Research Paper Chemistry of wood

Identification and Comparison of Metal Ions and Organic Compounds in Bamboo and Reed Stalks using Atomic Absorption, GC-MS Methods

Seyed Eshagh Ebadi

Volume 41, Issue 2 , June 2026, Pages 139-152

https://doi.org/10.22092/ijwpr.2026.370363.1811

Abstract

Background and Purpose: Due to the limited availability of raw materials required by Iran’s wood and paper industries, the utilization of lignocellulosic resources such as bagasse, reed, bamboo, cotton linters, cotton, kiwi pruning waste, rapeseed waste, and others plays a vital role in the country’s ... Read More Background and Purpose: Due to the limited availability of raw materials required by Iran’s wood and paper industries, the utilization of lignocellulosic resources such as bagasse, reed, bamboo, cotton linters, cotton, kiwi pruning waste, rapeseed waste, and others plays a vital role in the country’s fiber sector. Among these, bamboo and reed—being renewable resources—should not be overlooked, as their stalks can supply a portion of the non-wood lignocellulosic materials of Iran's industries‎. This study was conducted to identify the mineral elements and chemical components of organic ‎matter (in reed and bamboo stalks).Materials and methods: Thirty reed and bamboo stalks were selected and harvested from the western region of Mazandaran. Initially, stalks flour and ash content were prepared according to TAPPI standard methods. The types and concentrations of mineral elements were determined using 63% nitric acid and an atomic absorption spectrometer. Then, the extractive content of the samples was measured. The extractives were isolated using acetone solvent, and the remaining extract was transferred to a glass vial. BSTFA reagent was added, and the samples were heated in a water bath ‎(bain-marie bath)‎ at 70°C for one hour, followed by injection into the GC-MS system. Compound identification was based on the retention-time diagram, calculation of the Kovats index, and comparison with the Adams table.Findings: The results indicated that bamboo stalks had higher absorption levels of zinc, copper, and magnesium ions compared to reed. Conversely, reed stalks showed higher absorption of iron, lead, potassium, and manganese ions. GC-MS analysis revealed 96 compounds in reed stalks, with 2-Phenyl-N-methylaniline (25.99%), benzaldehyde (20.70%), 1,2-benzenedicarboxylic acid (11.48%), and xylene (1.16%) being the most prominent. In bamboo stalks, 104 compounds were identified, with benzaldehyde (46.43%), iron monocarbonyl (1.94%), bibenzyl (1.58%), and vanillin (0.09%) being the most abundant.Conclusion: The findings showed that magnesium had the highest absorption in reed, while lead had the lowest in bamboo. Chromatogram analysis identified nine compounds—xylene, benzaldehyde, benzyl chloride, benzene methanol, dodecane, tetradecane, bibenzyl, octadecane, and 1,2-benzenedicarboxylic acid—as common to both reed and bamboo. Vanillin and iron monocarbonyl were specific to bamboo, while bis (2-ethylhexyl) phthalate and gibberellin A3 were specific to reed. Among these, benzaldehyde was the most prevalent compound in both plants, indicating its potential role in the future applications of reed and bamboo stalks.

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Research Paper Physics and anatomy

Identification of ancient woods obtained from archaeological excavations in the Mansour-abad region of Yazd

Mohammad Emaminasab; Meysam Mehdinia; Hashem Rahamin; Kamyar Salehi; Roshanak Khatib Eghdami

Volume 41, Issue 2 , June 2026, Pages 153-166

https://doi.org/10.22092/ijwpr.2026.372427.1831

Abstract

Background and Objectives: Wood, as one of the most fundamental, renewable and biological materials, has played an important role in the development and advancement of human civilization. Accurate identification of archaeological wood can reveal patterns of natural resource exploitation and adaptive ... Read More Background and Objectives: Wood, as one of the most fundamental, renewable and biological materials, has played an important role in the development and advancement of human civilization. Accurate identification of archaeological wood can reveal patterns of natural resource exploitation and adaptive strategies of past populations to their surrounding environments. It also provides direct evidence for reconstructing past vegetation cover, timber trade networks, and the extent of human impact on ecosystems. Accordingly, the main objective of this study was the scientific identification of archaeological wood specimens recovered from excavations in the Mansur-abad region, Yazd Province, Iran.Materials and Methods: Six archaeological wood samples (three wooden scaffolding, two wooden basket, and one wooden shoe) obtained from the Geological Museum of the Geological Survey and Mineral Exploration were examined. Small samples were carefully removed from each specimen in accordance with museum regulations to minimize damage. For anatomical analysis, samples were softened in a solution of 98% ethanol, water, and glycerin. Thin sections (15 µm thick) were prepared in transverse, radial, and tangential sections using a sliding microtome. Sections were stained with 1% safranin solution, mounted on slides, and examined under a light microscope. Fiber maceration was carried out using Franklin’s method to measure cellular dimensions. Anatomical features were analyzed according to the feature list provided by the International Association of Wood Anatomists (IAWA).Results: All samples exhibited distinct growth ring boundaries. The basket sample, derived from a one-year-old branch with a single growth ring, contained less secondary xylem, and vessels were mostly solitary and occasionally radially arranged. In the wooden shoe sample, vessels showed a diagonal arrangement and were predominantly grouped in tangential and cluster patterns, especially in latewood. In the scaffolding samples, more than 90% of vessels were exclusively solitary. All specimens displayed simple perforation plates and alternate inter-vessel pits with diameters predominantly ranging from 4–7 µm. Helical thickenings, particularly in narrow vessels, and the presence of vascular tracheids were observed in all samples. Axial parenchyma was diffuse in the basket and scaffolding samples, and paratracheal in the shoe sample. Rays were generally wide and multi-seriate; they were homogeneous with procumbent cells in the scaffolding samples and heterogeneous in the others. Fiber maceration indicated longer vessel elements in the basket sample and shorter ones in the scaffolding and shoe samples. Evidence of biological degradation was observed in the cell walls of all specimens.Conclusion: Based on anatomical and morphological characteristics, the basket sample was identified as Amygdalus sp., the wooden shoe as Celtis sp., and the scaffolding samples as Elaeagnus angustifolia. Wild almond (Amygdalus scoparia) has a long, straight, and highly flexible shoots, making it one of the suitable species for basketry. In addition, the wood of Celtis has been appropriate for the manufacture of wooden footwear, and Elaeagnus angustifolia was a suitable choice for wooden mine scaffolding in the past time, due to its favorable physical and mechanical properties. Considering the distribution of these trees and shrubs in Yazd Province, whether cultivated or naturally occurring, their use in architectural structures and handicrafts reflects the detailed knowledge and efficient utilization of locally available woody resources by past communities.

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Research Paper Nano composite

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

Sead Majid Zabihzadeh; Seyedeh Motahareh Mohseni Shektai; Maryam Ghorbani Kokandeh; Ghasem Asadpur

Volume 41, Issue 2 , June 2026, Pages 167-184

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

Abstract

Background and Objective: The extensive use of petroleum-based polymers in the packaging industry and 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 Background and Objective: The extensive use of petroleum-based polymers in the packaging industry and 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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Research Paper Wood Modification and Wood Preservation

Influence of thermally modification on biological resistance and applied properties of wood

Reza Hajihassani; Sead Masoumeh Zamani; Fardad Golbabaei

Volume 41, Issue 2 , June 2026, Pages 185-197

https://doi.org/10.22092/ijwpr.2026.372631.1835

Abstract

Background and objectives: The purpose of this study was to investigate the effect of heat treatment on bio-durability and some physical and mechanical properties of two wood species (Fraxinus Sp. and Picea Sp.). So, thermo-wood samples were prepared from Fraxinus Sp. and Picea Sp. based on thermo-D ... Read More Background and objectives: The purpose of this study was to investigate the effect of heat treatment on bio-durability and some physical and mechanical properties of two wood species (Fraxinus Sp. and Picea Sp.). So, thermo-wood samples were prepared from Fraxinus Sp. and Picea Sp. based on thermo-D process. Heat-treated and untreated wood specimens were evaluated after exposing to white rot fungus for 16 weeks. The laccase activity and its effect on mass loss and wood density were also investigated. Moreover, some mechanical properties include impact strength and compression parallel to grain of both wood specimens was measured before and after exposing to fungus. The results showed that thermally modification improves the bio-durability of both wood species. The results also revealed reduction of mechanical properties due to heat treatment except compression parallel to grain.Materials and methods: In current study, the wood specimens were prepared from Ash and spruce woods. First, the prepared specimens were heat treated based on thermo-D process. Then, to investigate the biological resistance as well as physical and mechanical properties measurements, several specimens were prepared from heat treated and untreated wood. White rot fungus (Trametes versicolor) was used to evaluate the biological resistance of wood samples. Malt extract agar was also used as a culture medium. After preparing the white rot fungus, they were initially transferred on the culture medium in kolle dishes and then were placed inside the germinator to cover the surface of culture medium. Afterwards, the heat treated and untreated wood samples were exposed to the fungus and finally kolle dishes containing wood and fungus samples were transferred to the germinator. After 16 weeks, all specimens were taken from the germinator out and evaluated their physical and mechanical properties as well as biological resistance. The experiments included measurement of laccase activity, mass loss, density, impact strength and compression parallel to grain. The applied standards for physical, mechanical, and biological resistance experiments included EN113, ASTM D143-09, and ASTM D256. Eventually, the obtained results were statistically analyzed based on ANOVA method by SPSS software.Results: The results showed that the white rot fungus has been more efficiency on untreated specimens compared to thermo-wood in both wood species (Fraxinus Sp. and Picea Sp.). Therefor heat treatment improved the biological resistance, and also causes some changes in physical and mechanical properties of Ash and Spruce wood. The results also showed that thermal modification at high temperatures not only reduces the density of both woods, but also inhibited the reduction effect on density due to white rot fungus activity. Moreover, the results revealed that the compression parallel to grain of specimens was increased by heat treatment. On the other hand, reduction of this mechanical property due to the white rot fungus activity in thermo-wood samples was less than the controls. Evaluation of impact strength of specimens showed negative effect of heat treatment on this mechanical property. In addition, reduction of impact strength after exposure to the white rot fungus in heat treated specimens was higher than untreated.Conclusion: Based on the results, thermal modification can generally causes improvement of biological resistance, reduction of some physical and mechanical properties as well as more stability of applied properties of Ash and Spruce wood which is exposed to the white rot fungus.

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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

Identification of chemical compounds of Populus alba bark and wood using gas chromatography- mass spectrometry

Majid Kiaei

Articles in Press, Accepted Manuscript, Available Online from 20 May 2026

https://doi.org/10.22092/ijwpr.2026.372064.1828

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 ... Read More 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

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Research Paper

Quality Governance in Iran’s Recycled Paper Supply Chain: An Institutional Analysis and Reform Implications

Mohammad Reza Fathi; Kazem Teymouri

Articles in Press, Accepted Manuscript, Available Online from 25 May 2026

https://doi.org/10.22092/ijwpr.2026.372257.1829

Abstract

Background and Objective: The transition to a circular economy and the expansion of closed-loop supply chains have made recycled paper a strategic raw material in the paper industry. However, in reverse logistics and recycling chains, the quality of recycled materials is inherently uncertain, which affects ... Read More Background and Objective: The transition to a circular economy and the expansion of closed-loop supply chains have made recycled paper a strategic raw material in the paper industry. However, in reverse logistics and recycling chains, the quality of recycled materials is inherently uncertain, which affects production process stability, operational decisions, downtime and scrap costs, and market acceptance. In Iran as well, despite the economic and environmental inevitability of paper recycling, institutional and operational challenges have caused the quality of recycled inputs to remain variable and negotiable in many cases. Accordingly, this study aims to explain how “quality governance” is formed in Iran’s recycled paper supply chain, which boundary judgments and institutional assumptions reproduce the current quality situation, and, based on this understanding, what defensible reform implications and actionable recommendations can be proposed.Materials and Methods: This research adopted a qualitative approach, and its analytical framework is based on Critical Systems Heuristics and its twelve boundary questions. The logic of Critical Systems Heuristics relies on a systematic comparison between the current state and the desired state, making it possible to render explicit and open to critique the boundary judgments related to objectives, decision-making authority, valid knowledge, and the legitimacy of decisions. Data were collected through semi-structured interviews with 20 experts and key actors in the recycled paper supply chain. Participants were purposively selected from the main links of the chain and included managers and specialists from factories that use recycled paper (especially those responsible for procurement, production, and quality control), collection/sorting and processing actors, intermediaries and wholesalers, and individuals familiar with standards, testing, and oversight mechanisms. The experts’ professional activities were located in the country’s main hubs connected to the recycling network and the paper industry, and interviews were conducted to capture diverse perspectives in Tehran and Karaj, Isfahan, the northern provinces, and Khuzestan. After transcription, interview texts were coded using the twelve boundary questions and reorganized across four dimensions—motivation, control, knowledge, and legitimacy; then, to increase transparency and traceability, the results were translated into institutional axes and corresponding reform packages.Findings: The results showed that in the current state, the dominant goal of quality governance is largely focused on maintaining the flow of supply and transactions and ensuring short-term feedstock provision, while success criteria are defined mainly in economic and operational terms; therefore, quality is often reduced to the minimum level required for acceptance or continued production. In the control dimension, decision-making regarding acceptance/rejection, grading, and pricing is dispersed and multi-centered and, alongside some formal rules, remains significantly reliant on market conventions and case-by-case agreements. In addition, asymmetry in access to levers such as volume aggregation, market information, the ability to mix loads, access to large customers, and testing tools and results turns quality into a negotiable variable and reproduces quality fluctuations. In the knowledge dimension, although field experience plays a central role, the lack of integrated and reliable data and the absence of uniform procedures for sampling, testing, and producing defensible reports cause quality decisions and disputes to rely on informal information, limiting evidence-based dispute resolution. In the legitimacy dimension, weaknesses were observed in representation and accountability channels regarding quality claims and decisions; affected and cost-bearing groups do not necessarily have an effective ability to influence rules or follow up decisions, and as a result, the dominant logic tends toward a market-centered, transactional view.Conclusion: This study indicates that single-link or purely technical interventions are insufficient for sustainable quality improvement, and that reforming quality governance must simultaneously strengthen shared rules, reliable data, aligned incentives, and accountability. Based on the findings, four proposed executive reform packages are presented: (1) “standards and testing infrastructure” to turn quality into a measurable and defensible criterion through minimum indicators, uniform sampling/testing, and periodic audits; (2) “transparency and data governance” to reduce information asymmetry through a load quality sheet, record-keeping, and standardized access to documentation; (3) “quality-based contracts and incentive alignment” through quality-dependent pricing and reward/penalty mechanisms for nonconformance; and (4) “regulation, accountability, and dispute resolution” through clarified responsibilities and test-based arbitration. The gradual and coordinated implementation of these packages can enhance input quality stability, reduce the costs of poor quality, and improve supply reliability across the chain.

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Research Paper

Fabrication, Characterization and Evaluation of Technical Performance of Glass Fiber Reinforced (GFRP) Sandwich Panels with an Approach to Furniture Applications

meysam mehdinia; hamid zare; mosayeb dalvand; mohammad javad hassani

Articles in Press, Accepted Manuscript, Available Online from 26 May 2026

https://doi.org/10.22092/ijwpr.2026.372645.1836

Abstract

Background and objectives: The furniture industry, as one of the strategic sectors in the value chain of wood products, faces challenges such as increasing functional quality, reducing structural weight, increasing durability and reducing environmental impacts. The use of advanced materials and engineered ... Read More Background and objectives: The furniture industry, as one of the strategic sectors in the value chain of wood products, faces challenges such as increasing functional quality, reducing structural weight, increasing durability and reducing environmental impacts. The use of advanced materials and engineered structures can provide an effective solution to respond to these challenges. In the meantime, glass fiber reinforced (GFRP) sandwich panels are considered a promising option for furniture applications due to their high strength-to-weight ratio and ability to improve mechanical performance.The aim of this research is to investigate the manufacturing process and evaluate the technical performance of glass fiber reinforced sandwich panels and to assess the feasibility of their application in the panel furniture industry. Methodology: For this purpose, the effect of parameters including the type of glass fibers, fiber weight, type of resin used (two-component polyester and epoxy), and the arrangement of reinforcing layers (symmetrical and asymmetric) on the mechanical properties of the panels was investigated. The panels were produced with a honeycomb paper core and the reinforcing layers were attached to the surfaces using a lamination process. The samples were subjected to standard ASTM mechanical tests including bulk density, modulus of rupture, modulus of elasticity, edge pressure resistance, surface pressure resistance and shear strength. Results: The results showed that reinforcing sandwich panels with glass fibers significantly improved mechanical properties, especially flexural strength, modulus of elasticity and compressive and shear strengths. Also, the symmetrical arrangement of the reinforcing layers showed better structural performance than the asymmetrical arrangement due to a more uniform distribution of stresses.Conclusion: In summary, glass fiber reinforced sandwich panels, especially in symmetrical arrangements and using epoxy resin, are a suitable option for use in lightweight and durable panel furniture structures. In addition to improving mechanical performance, this approach can be effective in achieving sustainable development goals and optimizing resource consumption in the furniture industry by reducing raw material consumption and structural weight.Background and objectives: The furniture industry, as one of the strategic sectors in the value chain of wood products, faces challenges such as increasing functional quality, reducing structural weight, increasing durability and reducing environmental impacts. The use of advanced materials and engineered structures can provide an effective solution to respond to these challenges. In the meantime, glass fiber reinforced (GFRP) sandwich panels are considered a promising option for furniture applications due to their high strength-to-weight ratio and ability to improve mechanical performance.The aim of this research is to investigate the manufacturing process and evaluate the technical performance of glass fiber reinforced sandwich panels and to assess the feasibility of their application in the panel furniture industry. Methodology: For this purpose, the effect of parameters including the type of glass fibers, fiber weight, type of resin used (two-component polyester and epoxy), and the arrangement of reinforcing layers (symmetrical and asymmetric) on the mechanical properties of the panels was investigated. The panels were produced with a honeycomb paper core and the reinforcing layers were attached to the surfaces using a lamination process. The samples were subjected to standard ASTM mechanical tests including bulk density, modulus of rupture, modulus of elasticity, edge pressure resistance, surface pressure resistance and shear strength. Results: The results showed that reinforcing sandwich panels with glass fibers significantly improved mechanical properties, especially flexural strength, modulus of elasticity and compressive and shear strengths. Also, the symmetrical arrangement of the reinforcing layers showed better structural performance than the asymmetrical arrangement due to a more uniform distribution of stresses.Conclusion: In summary, glass fiber reinforced sandwich panels, especially in symmetrical arrangements and using epoxy resin, are a suitable option for use in lightweight and durable panel furniture structures. In addition to improving mechanical performance, this approach can be effective in achieving sustainable development goals and optimizing resource consumption in the furniture industry by reducing raw material consumption and structural weight.

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