Iranian Journal of Wood and Paper Science Research

Chemical conversion Chemical conversion

The Effect of Using Sericin-Modified Starch and Nanocellulose on the Properties of Paper Made from Old Corrugated Container (OCC)

hojjatullah akbari; fatemeh ravari; ghasem asadpur; Ashraf Sadat ghasemi

Volume 40, Issue 3 , October 2025

https://doi.org/10.22092/ijwpr.2025.368230.1795

Abstract

AbstractBackground and Objectives:The modification of paper components, including cellulose and chemical additives, through the incorporation of specific chemical agents plays a pivotal role in altering or reinforcing intermolecular bonding within the paper matrix. Such modifications can impart novel ... Read More AbstractBackground and Objectives:The modification of paper components, including cellulose and chemical additives, through the incorporation of specific chemical agents plays a pivotal role in altering or reinforcing intermolecular bonding within the paper matrix. Such modifications can impart novel characteristics that expand the functional applications of cellulose-based materials. The majority of strength-enhancing additives primarily rely on the formation of multiple hydrogen bonds to ensure their retention and effectiveness. Silk sericin, a natural macromolecule, is recognized as an adhesive-like protein (Figure 1). As a hydrophilic biopolymer, sericin exhibits excellent compatibility with other hydrophilic polymers, including starch, polyvinyl alcohol (PVA), and alginate. Due to its versatility and exceptional physicochemical properties, sericin has been extensively utilized in the fabrication of sponges, films, and hydrogels for diverse biomedical applications.The integration of biodegradable materials as alternatives to forest-derived resources holds significant importance in the papermaking industry. Although recycled pulp is widely used, a critical challenge remains the reduction in mechanical strength resulting from repeated recycling cycles. This study aims to modify starch and nanocellulose using sericin to exploit its polymeric properties for enhancing the mechanical performance of recycled paper. The research focuses on improving the physical and mechanical characteristics of paper produced from old corrugated container (OCC) pulp.Material and Methods:This study utilized sericin, nanocellulose, and starch. A nanocellulose-based hydrogel containing sericin was synthesized under controlled laboratory conditions. Functionalization of nanocellulose and starch was achieved via epichlorohydrin (ECH), wherein the hydroxyl groups of these materials reacted with the epoxy groups of ECH. The epoxide-functionalized nanocellulose and starch subsequently reacted with silk sericin, which contains amino acids with active side groups such as amine, carboxyl, and hydroxyl groups, leading to the formation of covalent or hydrogen bonds. The interaction between the amine and amide groups of sericin and the hydroxyl groups of nanocellulose and starch resulted in the establishment of hydrogen bonds, thereby forming the final composite material.The structural modifications of starch and nanocellulose were characterized using instrumental techniques such as Fourier Transform Infrared Spectroscopy (FT-IR), confirming the successful formation of starch-sericin and nanocellulose-sericin compounds. The modified materials were incorporated into recycled pulp at varying ratios (20/70, 30/70, 40/70, and 50/70), with 70% of the composition consisting of recycled pulp. Handmade paper samples with a grammage of 60 g/m² were produced, and their mechanical properties, including tensile strength index, tear length, burst strength index, tear resistance index, and freeness degree, were evaluated in accordance with relevant standards.Results:The incorporation of starch and nanocellulose modified with sericin resulted in a statistically significant enhancement of tensile strength, burst strength, and tear resistance in the recycled paper samples. The greatest improvement was observed in the samples containing 20/70 modified starch. The addition of these modified materials positively influenced the mechanical properties of the paper. Given that these additives do not intrinsically alter the inherent strength of the cellulose fibers, the observed changes in tensile strength are likely attributable to an increase or decrease in fiber bonding. This enhancement may stem from the penetration of the applied materials into the interfiber voids, thereby reinforcing the fiber network. Conversely, at higher sericin concentrations, a marginal decline in certain mechanical properties was observed in specific ratios.Tear resistance is a crucial parameter in paper evaluation, influenced by factors such as average fiber length, intrinsic fiber strength, fiber bonding, and fiber orientation. In this study, fiber bonding and orientation were identified as the most significant contributors to the observed mechanical behavior. The incorporation of sericin-modified nanocellulose led to increased air resistance and facilitated a more uniform fiber distribution within the paper structure, indirectly indicating improvements in internal bonding and sheet formation quality. Furthermore, the addition of modified starch and nanocellulose resulted in a reduction in pulp freeness across the tested compositions.Conclusion:The findings of this study demonstrate the successful bonding of sericin with starch and nanocellulose, leading to structural modifications that improve their functional properties. The utilization of sericin-modified starch and nanocellulose presents an effective and environmentally sustainable approach to enhancing the mechanical performance of recycled paper. This strategy not only improves the overall quality of paper products but also represents a significant advancement toward sustainable development through the utilization of renewable bio-based materials.

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Research Paper Pulp and paper

Effect of Diammonium Phosphate and Nanoclay on the Flame Retardancy and Strength Properties of Paper Made from Bagasse Soda Pulp

soleiman zaheri; Ali Ghasemian; Mohammadreza Dehghani Firouzabadi; Ghasem Asadpur

Volume 40, Issue 3 , October 2025

https://doi.org/10.22092/ijwpr.2025.368847.1800

Abstract

AbstractBackground and Objective:Cellulose-based paper is an important renewable resource composed of cellulose, hemicellulose, and lignin. Due to its advantages such as lightweight, flexibility, low cost, and environmental friendliness, it is widely used. However, cellulose-based paper is inherently ... Read More AbstractBackground and Objective:Cellulose-based paper is an important renewable resource composed of cellulose, hemicellulose, and lignin. Due to its advantages such as lightweight, flexibility, low cost, and environmental friendliness, it is widely used. However, cellulose-based paper is inherently flammable. As a result, modifying paper with organic flame retardants is of great significance to reduce fire hazards and expand the application range of cellulose-based paper. This study investigates the effect of diammonium phosphate and nanoclay, in combination with cationic starch, on the properties of paper produced from bagasse soda pulp.Materials and Methods:For this purpose, paper was obtained from bagasse soda pulp at Pars Paper Factory, with a basis weight of 120 g/m² and an average thickness of 0.185 mm. The paper was then coated with different concentrations of diammonium phosphate and nanoclay (10, 20, and 30%) along with 10% cationic starch. The coating process was carried out using an Auto Bar Coater, and the samples were dried in an oven at 60–65°C for 10 minutes. After drying, the samples were kept at room temperature for 2 days. Various tests were conducted on the samples, including liquid penetration resistance (Cobb test), thickness, contact angle, tensile strength, burst resistance, and tear resistance. Additionally, the fire-related properties of the paper, including thermal stability, burning behavior, and vertical flammability, were evaluated.Results:Coating paper with diammonium phosphate (DAP) and montmorillonite nanoclay in the presence of cationic starch improved the paper's hydrophobic properties and flame resistance. However, overall, the DAP-coated papers demonstrated better performance compared to those coated with nanoclay. This superiority is due to the formation of uniform layers and the blockage of surface pores, which prevents water penetration and increases hydrophobicity compared to nanoclay-coated and control samples. The use of DAP at an optimal concentration of 20% increased tensile strength but led to a reduction in tear and burst strength. At higher concentrations, this coating played a more effective role in enhancing the mechanical properties of the paper.Increasing the concentration of diammonium phosphate to 30% significantly increased the char yield, indicating improved thermal resistance of the paper. Both coating materials reduced the thermal decomposition temperature and increased the char yield, acting as barriers to prevent further combustion. In vertical flammability tests, DAP-coated papers at higher concentrations exhibited shorter ignition times and lower char lengths, displaying self-extinguishing behavior.The results of Fourier-transform infrared spectroscopy (FTIR) confirmed the flame-retardant performance in the condensed phase. Furthermore, the thermogravimetric analysis (TGA) of the samples showed that the treated samples had the highest char residue percentage compared to the control sample. The flame propagation pattern analysis also indicated improved fire resistance properties in the treated samples compared to the untreated ones. Additionally, all strength properties (such as tensile strength, burst strength, and tear strength) improved in the treated samples.Overall, this study demonstrated that coating with diammonium phosphate and nanoclay in the presence of cationic starch significantly improves the physical and flame resistance properties of bagasse paper. Notably, using DAP at a 30% concentration increased the char yield to 48.165%, equivalent to a 133% increase compared to the control sample and a 111% increase compared to nanoclay. These findings confirm that modifying paper made from bagasse soda pulp with this combination enables the production of paper with high flame-retardant properties, favorable char yield, and no emission of harmful substances such as halogens or formaldehyde.Conclusion:Overall, the use of diammonium phosphate and nanoclay in the presence of cationic starch as coating materials can improve the physical and mechanical properties of bagasse-based paper and make it more suitable for flame-resistant applications. Thus, these treated paper sheets can be used as fire-resistant paper-based materials.

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Research Paper Wood Modification and Wood Preservation

Mechanical properties of date palm wood; behavior of some characteristics after thermal modification treatment

mostafa maleki golandouz; ali Bayatkashkoli; Hadi Gholamiyan; Mahmoud Reza Hosseini Tabatabaei; Saeed Reza farrokhpayam

Volume 40, Issue 3 , October 2025

https://doi.org/10.22092/ijwpr.2025.368376.1796

Abstract

AbstractBackground and Objective: Date palm is one of the important sources of lignocellulosic materials in Iran. The structure of date palm wood is a monocot plant and is very different from the wood of dicot trees. This raw material needed to be studied, therefore, an environmentally friendly approach ... Read More AbstractBackground and Objective: Date palm is one of the important sources of lignocellulosic materials in Iran. The structure of date palm wood is a monocot plant and is very different from the wood of dicot trees. This raw material needed to be studied, therefore, an environmentally friendly approach to date palm modification and the behavior of some mechanical properties for use in the wood and furniture industry was investigated.Materials and Methods: Four date palms were obtained from Sistan and Baluchestan province in Zabol city. The trunks were cut into four two-meter sections along the trunk for lightness and ease of transportation in the wood cutting workshop of the Faculty of Natural Resources, Zabol University. Test samples were prepared from different positions along the cross sections and at different heights inside the trunk. The aforementioned samples were prepared and prepared for mechanical testing and thermal modification. To determine the mechanical properties before modification, tests of tensile strength parallel to the vascular bundles, tensile strength perpendicular to the vascular bundles, shear strength parallel to the vascular bundles, and compressive strength parallel to the vascular bundles were performed. The test specimens were modified for heat treatment in a heat chamber (oven) at 11 different temperatures (120 to 210°C) by maintaining a constant temperature for 2 hours and the same time. The behavior of some properties including flexural strength, modulus of elasticity, roughness meter, and resistance to screws and nails were tested before and after the thermal modification operation for the suitability in the furniture industry. Analysis of variance of heat treatment was performed at different temperatures.Results: The results showed that the average mechanical properties before modification, tensile strength tests parallel to vascular bundles, tensile strength perpendicular to vascular bundles, shear strength parallel to vascular bundles, and compressive strength parallel to vascular bundles were determined with an average of 85.07, 1.31, 3.58, and 19.79 kg/cm2, respectively. During the modification operation, light smoke and a very fragrant odor with a pleasant aroma were emitted in the laboratory. This phenomenon was one of the signs of changes in the properties of date palm after modification. Also, the behavior of some properties, including the bending strength (MOR) of unmodified and modified date palm samples, was recorded with an average of 39.109 and 70.719 kg/cm2, respectively. The highest average modulus of elasticity (MOE) was calculated to be 2356.38 and 2677.57 kg/cm2, respectively. The modification process at different temperatures showed that in the temperature range of 160 oC, an increase in MOR and an increase in MOE occurred. However, with increasing heat treatment temperature in subsequent samples, the MOR and MOE values decreased. In the 210 oC treatment, the samples had almost a superficial burn state. Also, the screw resistance test showed an increase in resistance compared to the nail after modification. The results of the roughness test after modification, in the temperature range of 150 and 160 oC, witnessed a low level of surface changes and smoothness. Conclusion: Referring to this research, it is the beginning of entering into creating basic knowledge for thermal modification of date palm wood. Overall, it offers promising ways to tailor the properties of this lignocellulosic material to suit different applications while maintaining its renewable and environmentally friendly nature. Embracing these advances may pave the way for the development of these innovative and sustainable materials in the wood, furniture, and home interior industries in the coming years.

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Research Paper Chemistry of wood

Aging and Starch Sizing are influential factors in the identification of historical papers with the FTIR-ATR spectroscopy method

Mohadeseh hosseini someah; Mehrnaz Azadi Boyaghchi; Kambiz Pourtahmasi; Maryam Afsharpour; Samad Nejad Ebrahimi

Volume 40, Issue 3 , October 2025

https://doi.org/10.22092/ijwpr.2025.100916.1792

Abstract

Background and Objectives: Historical papers identifying is one of the important stages of studying archival and paper works that ensure its proper conservation. Historical papers consist of fibers with organic carbohydrate compounds such as cellulose and hemicelluloses and lignin. The small amount of ... Read More Background and Objectives: Historical papers identifying is one of the important stages of studying archival and paper works that ensure its proper conservation. Historical papers consist of fibers with organic carbohydrate compounds such as cellulose and hemicelluloses and lignin. The small amount of lignin and alkaline fillers has made them last longer. In addition, the presence of Starch Sizing has increased its resistance as it creates a suitable level of writing. Many instrumental methods have been used to identify historical papers, including infrared spectroscopy. This research aims to investigate the effect of aging and sizing changes on two types of historical papers known as Samarqand and Daulatabad with this device method.Materials and methods: Among of the historical papers 8 samples were randomly selected. These samples were all selected with the characteristics of self-color and the same starch sizing content, which were measured using Logel's test for this purpose. Artificial aging test was used to investigate the changes in the internal structure of papers as well as the stains on the surface of historical papers, which is an accelerated method of destroying the molecular structure of organic materials of paper. To prepare the samples, about 5 g of historical paper samples D2 and S4 were removed and placed for 24 hours at 23°C and 50% relative humidity. Then they were transferred to the incubator for 24 days for accelerated aging test at 80°C temperature and 65% relative humidity. FTIR Spectroscopy was used in Tehran Art University. This model device is TENSOR 27 made by Bruker Germany company with ZnSe crystal analyzer surface and attenuated total reflection method in the range of 400 cm-1 to 4000 cm-1.Results: After two cycle of 12 days (576 hours and approximately equivalent to 50 years), the acidity values in two historical paper samples show a decrease in the pH number value. These values reveal the oxidation of cellulose, which is caused by the combined process of thermal and moisture accelerated aging. The results of increasing the acidity of the papers showed clear peaks in the region of 1730 cm-1 or increased their intensity. These absorption bands correspond to C=O bonds in the carbonyl groups, which were absent compared to the samples before aging and became apparent after aging. The comparison between two historical papers aged for 50 years more than the original paper samples in FTIR-ATR spectroscopy show that after aging, the intensity of cellulose and organic compounds has decreased compared to lignin and with the increase of lignin peak intensity in the region 1595 cm -1 has revealed itself. And these two samples are placed at a higher and farther height compared to their original paper samples, which is due to the increase in the amount of lignin compared to the amount of cellulose and organic compounds. Therefore, the role of aging and change of acidity in the change of fiber identification points according to the Garside diagram is wrong. Also, the effect of the external factor of starch food is also shown by the change in wave numbers and their intensity in the main points of 1595 cm-1, 1105 cm-1 and 2900 cm-1. In the spectroscopy of the original paper, the reduction of the peak intensity is quite evident, and this shows that the starch sizing has led to the covering of the paper surface and ultimately the reduction of the intensity of the spectrum. Therefore, by washing the papers, the intensity has changed and the amount of lignin has decreased slightly, but the measure of organic compounds and cellulose has increased.Conclusion: The result showed that the amount of acidity that appears with the increase of age and with the increase of lignin in historical papers has an effect on the intensity points obtained from FTIR-ATR spectroscopy and shifts them in the Garside diagram. Also, starch sizing is another factor that plays a significant role in changing the data of the Garside diagram in the identification of historical paper fibers and they show different points. Therefore, starch sizing and the aging process, which is related to the change in the amount of acidification of historical papers, affect the FTIR-ATR spectroscopy.

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Pulp and Paper Pulp and paper

The potential of using cotton linter as imported long fiber in newsprint production

Ramin Vaysi; Hossien Resalati; Rabi Behrooze

Volume 40, Issue 3 , October 2025

https://doi.org/10.22092/ijwpr.2025.369326.1803

Abstract

Background and aim: Currently, in Iran, CMP pulp and newsprint are produced from about 50% birch, 20% poplar, and about 30% mixtures of other wood species. To improve the strength properties and runbility of the papers during production and printing, it is necessary to use about 17% imported long fibers. ... Read More Background and aim: Currently, in Iran, CMP pulp and newsprint are produced from about 50% birch, 20% poplar, and about 30% mixtures of other wood species. To improve the strength properties and runbility of the papers during production and printing, it is necessary to use about 17% imported long fibers. This imported pulp, which is usually coniferous kraft pulp and is imported into Iran from other countries (Finland), creates dependency and causes large amounts of foreign exchange to be spent and withdrawn from the country annually. On the other hand, in the Behshahr Linter-Pak factory, which is located in distance about 50 kilometers from Mazandaran Wood and Paper industries (MWPI), more than 10,000 tons of purified cotton linter are produced annually. Which is of great importance due to its convenient availability, ease and low cost of transporting the material. For this purpose, this research was conducted with the aim of using cotton linter instead of imported long fiber pulp in newsprint.Materials and methods: To conduct this research, test samples of purified cotton linter from the Behshahr Linter-Pak factory, imported long fiber pulp and CMP pulp from the MWPI were randomly selected. In the first stage, freeness, fiber classification and biometric properties of their fibers were measured. Then, using a PFI mill laboratory refiner, imported long fiber pulp and cotton linter were refined to freeness of 500, 450, and 400 CSF, and CMP pulp was refined to freeness of CSF450, 400, and 350 CSF. In the next step, the refined pulp of imported long fibers and cotton linters was mixed separately and in proportions of 10, 15, 20, and 25 percent with the CMP pulp of MWPI. The handsheets with a basis weight of 60 gr/m2 was prepared from selected samples and according to TAPPI standard tests. A spectrophotometer was used to measure the optical properties of the prepared papers, accordingly, the brightness, yellowness and opacity of handsheets was determined. Then, the strength properties, especially the tear strength, burst, tensile and breaking length of the handsheets were measured and compared using standard TAPPI tests.Results: The results of the classification of cotton linter fibers and imported long fibers showed that the weight percentage of long fibers (14 and 48 meshes) of cotton linter and its dispersion were higher and its fine particles (fines) were lower than imported long fibers. Biometric characteristics of cotton linter fibers and imported long fibers showed that the average fiber length, felting and flexibility coefficients of cotton linter fibers were higher, and their total diameter, lumen diameter, double wall thickness, and Runkel coefficient were lower than those of imported long fibers. Also, with increasing refining rounds (rpm), the freeness in long fibers and cotton linter showed a decreasing trend. By increasing the percentage of cotton linter and imported long fibers mixed from 10 to 25 percent, the brightness and yellowness of the handsheets improved and its opacity decreased. By adding long fibers and cotton linter and a mixture of cotton linter + long fibers from 10 to 25% to CMP pulp, tensile, burst, tear strengths, and breaking length increased. This increase is milder with the addition of cotton linter to CMP pulp. The paper made from adding cotton linter to CMP pulp has always had the lowest strength properties, and paper made from adding imported long fibers to CMP pulp has had the highest strength properties.Discussion: Given that cotton linter does not respond well to refining due to its crystalline structure, beater may be more suitable due to its longer and gentler refining. In this regard, the strength properties of paper made from cotton linters have always been lower than those of imported long- fibers. However, the use of a mixture of cotton linter + long fibers, especially in freeness of 400 and 450 CSF, can replace a portion of imported long fibers in newsprint due to its suitable optical and strength properties comparable to imported long fibers.

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Pulp and Paper Pulp and paper

Evaluation of the effect of coating with graphene, Zein-Fluorine on the physical properties and printability of white liner paper from Mazandaran Wood and Paper Factory

Jafar Ebrahimpour Kasmani; Ahmad Samariha

Volume 40, Issue 3 , October 2025

https://doi.org/10.22092/ijwpr.2025.369187.1802

Abstract

Paper and cardboard, as biodegradable and lightweight materials, are widely used in the packaging of various industries. Coating paper improves its properties and enhances print quality. Biopolymer coatings have advantages over conventional polymers due to their biodegradability and non-toxicity. The ... Read More Paper and cardboard, as biodegradable and lightweight materials, are widely used in the packaging of various industries. Coating paper improves its properties and enhances print quality. Biopolymer coatings have advantages over conventional polymers due to their biodegradability and non-toxicity. The aim of this study is to prepare a coated cardboard sheet with nanomaterials and mineral compounds as a packaging tool and to evaluate the physical properties and printability of white liner paper from Mazandaran Wood and Paper Company. Various amounts of three materials—nanographene, zein protein, and fluorine—along with an acrylamide resin were used for coating the paper using a blade method. The properties examined included thickness, ash paper content, air permeability, roughness, opacity, whiteness, brightness, yellowness, gloss, optical density, and adhesion. This research investigates the effect of surface coating of cardboard (top liner) with nanographene, protein solutions, and mineral materials. Therefore, the goal of this study is to create a barrier against air permeation by coating the outer surface of the cardboard (top liner) with one or more layers of coating that include nanographene, protein solutions, and mineral materials. This coating is designed as the first layer of the cardboard that is in direct contact with the outside, aiming not only to reduce the interaction between the inside and outside of the cardboard but also to enhance printability.Methodology: The white liner paper with a basis weight of 110 grams was obtained from the Mazandaran Wood and Paper Company. The AO-4 type nanographene was sourced from Graphene Supermarket in the USA, zein protein from Sigma Aldrich, and fluorine from the Minekavan production group. For coating, nanographene, zein, and fluorine were weighed according to specified weight percentages and mixed with 100 grams of distilled water at 50 degrees Celsius for 30 minutes, depending on the treatment conditions. Then, 2.5 grams of styrene-butadiene latex and 0.5 grams of dispersant D200 were added to the mixture and homogenized for 20 minutes at 1500 RPM. A 5% cationic starch solution was also used as a retention aid to enhance the coating. The physical and optical properties were measured according to standard methods. The experimental design was completely randomized. Data analysis was performed using one-way analysis of variance and Duncan's test at a 95% confidence level.Results: The results of the one-way analysis of variance indicated that there is not a significant difference in thickness, ash content, air permeability, roughness, opacity, whiteness, brightness, yellowness, gloss, and optical density of these papers at a 5% probability level. The greatest thickness is associated with the white liner paper coated with zein and fluorine, while the least thickness belongs to the control sample. Regarding ash content, the highest amount is found in the white liner paper coated with fluorine and graphene. For air permeability, the paper coated with fluorine and nanographene shows the best performance. Roughness results indicate that the white liner paper coated with zein and fluorine has the highest roughness. Additionally, the lowest levels opacity and whiteness are related to the white liner paper coated with zein, nanographene, and fluorine. The adhesion test showed that the coated layers and flexo composite adhered well to the paper.The results obtained from microscopic studies showed that the addition of nanographene, zein, and fluorine improved the quality of the fiber coating on the paper, and using the laboratory coating method allowed for a more uniform surface to be created on the paper. A significant increase in paper thickness was observed, attributed to changes in the thickness of the base paper. Air permeability increased significantly with coating, and in some cases, this resistance was so high that it could not be measured. The use of fluorine and zein resulted in maximum roughness, while nanographene produced the least roughness. Additionally, the opacity of the papers decreased after coating. Furthermore, optical density improved in the composite coatings, indicating better print quality. The results suggest that the adhesion of the coating layer to the flexo ink was excellent, and compared to the uncoated samples, the amount of paper delamination was lower.

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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.

Physics and Mechanical Wood

Investigation of Physical and Mechanical Properties of Walnut Wood (Juglans regia) from Barkala Region, Kordkuy County, Golestan Province

mohammad najafianashrafi

Articles in Press, Accepted Manuscript, Available Online from 21 July 2025

https://doi.org/10.22092/ijwpr.2025.369404.1804

Abstract

AbstractBackground and Objective: Wood is a unique renewable natural resource that plays a vital role in the socio-economic development of countries. Walnut (Juglans regia) is a durable and thick-trunked tree species found in temperate and subtropical forests of Asia, Europe, and America. In Iran, it ... Read More AbstractBackground and Objective: Wood is a unique renewable natural resource that plays a vital role in the socio-economic development of countries. Walnut (Juglans regia) is a durable and thick-trunked tree species found in temperate and subtropical forests of Asia, Europe, and America. In Iran, it is one of the most important wood species, widely used in industries such as furniture, veneer, and construction panels. Therefore, obtaining detailed physical and mechanical characteristics of this species is essential.Materials and Methods: In this study, sampling was carried out from walnut trees in the forests of Barkala village, Kordkuy County (Golestan Province), at an altitude of 1434 meters above sea level. Three healthy trees were randomly selected and harvested. The average diameter at breast height was 51.3 cm, and the average age of the trees was approximately 51 years. Tests were conducted according to ISO 3129 and ASTM D-143 standards for physical and mechanical properties, respectively. Approximately 319 samples were tested for physical properties and 246 for mechanical properties. Physical characteristics examined included oven-dry density, basic density, green density, maximum moisture content, shrinkage, and swelling. Mechanical properties included bending strength, modulus of elasticity, compression parallel to grain, tensile strength (parallel and perpendicular), shear strength parallel to grain, hardness, and cleavage resistance. The samples prepared for mechanical tests were placed in a climate chamber for four weeks at a temperature of 20 degrees and a relative humidity of 65 percent so that the humidity of all samples during mechanical tests was 12. To perform mechanical tests, a SANTOM 150 machine with appropriate load cells for each test located at Imam Mohammad Baqer National University of Skills and Knowledge, Sari, was used.Results: The green, oven-dry, and basic densities were found to be 1.16, 0.63, and 0.54 g/cm³, respectively. Longitudinal, radial, tangential, and volumetric shrinkage were 0.4%, 5.65%, 8.30%, and 14.35%, respectively. Corresponding swelling values were 0.51%, 5.71%, 8.88%, and 15.1%, and the maximum moisture content reached 105.14%. Mechanical properties measured included: bending strength (102.46 N/mm²), modulus of elasticity (10246.02 N/mm²), compression parallel to grain (34.11 N/mm²), tensile strength parallel and perpendicular to grain (146.17 and 9.66 N/mm²), shear strength parallel to grain (11.54 N/mm²), hardness (6622.70 N), and cleavage resistance (1.69 N/mm²). The results obtained show the positive effect of age on the mechanical properties of wood. Of course, factors such as geographical factors and altitude above sea level also have an effect on the physical properties of wood, such as swelling and elongation of wood. Of course, in this study, it was found that the effect of tree age on the mechanical properties of wood has a completely positive effect.Conclusion: The walnut trees from the Barkala region of Kordkuy in Golestan Province showed favorable density and generally superior mechanical properties compared to walnut wood from four other provinces previously studied. This may be due to the higher average age of the trees in this region. Given the strong mechanical properties, this wood is well-suited for use in parquet flooring, furniture, veneer, and construction panels.

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Composite Wood Products

The Role of Nano Calcium Carbonate in Improving the Mechanical Properties of Poplar Wood Flour and Recycled Polypropylene Nanocomposites

Alireza KHAKIFIROOZ; Ahmad Samariha; Hirsa Jouya Ardekani

Articles in Press, Accepted Manuscript, Available Online from 20 August 2025

https://doi.org/10.22092/ijwpr.2025.369762.1807

Abstract

Background and objectives: Given the increasing use of nanocomposites in various industries, improving the mechanical and physical properties of these materials has become particularly important. Nanocomposites, due to their combination of different materials, exhibit unique features such as lightness, ... Read More Background and objectives: Given the increasing use of nanocomposites in various industries, improving the mechanical and physical properties of these materials has become particularly important. Nanocomposites, due to their combination of different materials, exhibit unique features such as lightness, strength, and resistance to environmental factors. In this context, calcium carbonate nanoparticles are recognized as an effective reinforcing agent that can enhance the performance of poplar wood flour and recycled polypropylene nanocomposites. This research examines the impact of calcium carbonate nanoparticle content on the mechanical properties of these nanocomposites. As a reinforcing material, calcium carbonate nanoparticles can improve mechanical properties by enhancing adhesion and stress transfer between different phases of the nanocomposite. The main objective of this study is to evaluate the effects of the size and amount of calcium carbonate nanoparticles on the elastic modulus, tensile strength, and other mechanical characteristics of the nanocomposites. Given the diversity of applications for nanocomposites in packaging, automotive, and construction industries, the results of this study could contribute to the development of lightweight and durable materials in these sectors. Additionally, this research could provide strategies for the optimal use of recycled materials, which in turn would help preserve the environment and reduce costs.Methodology: For this purpose, polypropylene was used at three levels (50%, 60%, and 70%), poplar wood flour at three levels (30%, 40%, and 50%), and calcium carbonate nanoparticles at four levels (0%, 1%, 2%, and 3% by weight). Additionally, maleic anhydride grafted polypropylene was included at a fixed level of 3%. These materials were mixed using a twin-screw extruder, and standard test samples were produced using the injection molding method. Subsequently, mechanical properties, including tensile and flexural strength, tensile and flexural modulus, impact resistance, and hardness, were measured according to ASTM standards D 638, D 747, D 256, D 224, and D 703.Results: The results related to the F-value and significance level indicated that the effect of wood flour content on mechanical properties, including tensile strength, flexural strength, tensile and flexural modulus, impact resistance, and hardness, was significant at the 95 percent confidence level. Additionally, the effect of nano calcium carbonate on tensile and flexural strength, flexural modulus, and hardness was also significant at the 95 percent confidence level, whereas the flexural modulus and impact resistance were not significant at this level. The interaction effects between wood flour and nano calcium carbonate on all resistances were not significant at the 95 percent confidence level.Conclusion: The findings of this research indicate that increasing the amount of poplar wood flour from 30 to 50 percent has a significant impact on the mechanical properties of nanocomposites, particularly in enhancing tensile and flexural strength, modulus, and hardness. This improvement is attributed to increased adhesion and stress transfer between phases. However, the increase in wood flour content leads to reduced impact resistance and greater brittleness of the composite. Adding nano calcium carbonate up to 3 weight percent also improves mechanical properties, but similarly to wood flour, it reduces impact resistance. Overall, the appropriate selection of the type and amount of additives can enhance the performance of nanocomposites, while attention to negative effects such as reduced impact resistance is also essential.

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