Iranian Journal of Wood and Paper Science Research

Editorial

Volume 40 Issue 2 Summer - Serial Number 91

Volume 40, Issue 2 , May 2025

https://doi.org/10.22092/ijwpr.2025.133808

Abstract

Editorial

Research Paper Management and Economics wood

Identifying and ranking the characteristics of agile attitude in the successful implementation of agility in the wooden furniture and decoration industry using the Fuzzy Delphi and Fuzzy FUCOM

Hamidreza Talaie; Shahab Bayatzadeh

Volume 40, Issue 2 , May 2025, Pages 95-111

https://doi.org/10.22092/ijwpr.2025.368220.1794

Abstract

Background and Objective: The wood industry in Iran is one of the key industries with high potential for the production of products such as furniture and interior decoration. However, this industry faces challenges such as traditional structures, lack of modern skills, and limited use of digital technologies, ... Read More Background and Objective: The wood industry in Iran is one of the key industries with high potential for the production of products such as furniture and interior decoration. However, this industry faces challenges such as traditional structures, lack of modern skills, and limited use of digital technologies, which hinder its competitiveness in both domestic and international markets. Agile thinking, as a strategic approach, can address these issues by enhancing flexibility, quick response capabilities, and continuous learning, paving the way for sustainable growth. This research aims to identify and rank the characteristics of agile thinking and introduce and localize the necessary tools for successful agility implementation in Iran’s furniture and wood decoration industry. The significance of this topic lies in improving competitiveness, reducing costs, and adapting to environmental and market changes. Materials and Methods: This descriptive-survey research, with an analytical approach and practical results, utilizes the fuzzy Delphi and fuzzy Fuzzy Order of Comparison (FOC) methods to identify and weigh the factors of agile thinking. In the first step, 17 main factors were identified through a review of literature and previous studies. These factors included characteristics such as flexibility, continuous learning, failure management, and continuous improvement. Then, using a fuzzy Delphi questionnaire, which was provided to 10 experts in the wood and furniture industry, the factors were confirmed and prioritized. In the fuzzy Delphi process, linguistic terms and triangular fuzzy numbers were used to analyze the data, and after two rounds, 12 factors were finally confirmed. In the next step, the fuzzy FOC method was employed to weigh these factors. This method, using fuzzy pairwise comparisons and analysis of the defined constraints in the model, calculated the final weights of the factors. All calculations were performed using LINGO 18 software. Results: Flexibility, with a weight of 33.5%, was identified as the most important factor. This factor includes sub-factors such as open-mindedness, adequate information, and adaptability to changes, which play a vital role in responding quickly to environmental changes. Failure management, with a weight of 32.8%, was also a prominent factor and includes components such as accepting failure and constructive criticism, which help in learning from past experiences. Learning new skills (18.2%) focusing on in-service training, digital infrastructure, and skill development enhances the capabilities of employees and organizations. Continuous improvement (15.6%), including time management, strengthening accountability, and creating a trust-based environment, contributes to increasing productivity and quality of organizational processes. Data analysis revealed that flexibility and failure management, especially in dynamic industrial environments like the wood industry, play crucial roles in organizational success. Additionally, employee training and fostering a culture of continuous learning are effective tools for adapting to rapid technological and market changes. Conclusion: The findings suggest that strengthening the agile mindset, including flexibility, continuous learning, and failure management, can enhance agility in Iran’s wood industry and improve its competitiveness in domestic and international markets. These results emphasize the importance of investing in employee training, developing digital infrastructure, and promoting a culture of accepting failure. Moreover, implementing these approaches can improve organizational performance, increase sustainability, and accelerate the transformation of this industry, paving the way for sustainable growth.

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Research Paper Composite wood products

Evaluation of engineering characteristic of particleboard made from rice husk and industrial wood particles

Reza Hajihassani; kamyar salehi; Fardad Golbabaei; Hashem Rahamin; meysam mehdinia

Volume 40, Issue 2 , May 2025, Pages 112-123

https://doi.org/10.22092/ijwpr.2025.368862.1801

Abstract

Background and Objectives: The country's forest resources limitation and prohibition of wood import, have caused several problems in providing lignocellulosic raw materials. Therefore, the use of lignocellulosic waste resources shows important role in this field. Particleboard is one of the wood composite ... Read More Background and Objectives: The country's forest resources limitation and prohibition of wood import, have caused several problems in providing lignocellulosic raw materials. Therefore, the use of lignocellulosic waste resources shows important role in this field. Particleboard is one of the wood composite products which can be produced using various types of lignocellulosic materials such as agricultural residue. One of the available agricultural wastes in the country is rice husk, which can be used in production of particleboard. However, the use of agricultural lignocellulosic residues impose negative impact on engineering characteristic of produced boards. Therefore, the objective of this research is to evaluate the possibility of rice husk application in particleboard production and also obtain an optimal composition of raw material and the other production conditions.Methodology: Rice husk and industrial wood particles were collected from the Gilan province and 22 Bahman Particleboard Company, respectively. The steps in particleboard production included screening, drying, gluing, formation and pressing. In this study, the composition of raw material (100% industrial wood particles, 90% industrial wood particles and 10% rice husk, 80% industrial wood particles and 20% rice husk, 70% industrial wood particles and 30% rice husk) was considered as a variable factor and the other factors including the resin consumption (10% based on dry weight of the board), pressing temperature (180 °C), pressing pressure (25 kg/cm2) and pressing time (4 minutes) were considered as fixed factors. A total of 12 laboratory boards with three replications were produced for each treatment. Then, the samples were prepared from each board according to the EN326-1 guidelines. Physical and mechanical tests included measurement of water absorption and thickness swelling after 2 and 24 hours of immersion in water, bending strength, modulus of elasticity and internal bonding. The results were analyzed based on a complete randomized design within the framework of a factorial experiment by SPSS software. Duncan's multiple range test was used to compare mean values.Results: The results of this study showed that the composition of raw materials affects all physical and mechanical properties of manufactured boards. Increasing of rice husk consumption decreased the bending strength, modulus of elasticity and internal bonding and also increased the water absorption and thickness swelling after 2 and 24 hours immersion in water.Conclusion: In general, the results of current study revealed that consumption of rice husk in small quantity (up to 10% composition of the raw material) can provide boards with acceptable physical and mechanical properties; but higher amounts, lead to a decrease in physical and mechanical properties of the boards. Therefore, small amounts of rice husk can be used as substituted raw materials in combination with industrial wood particles in particleboard industry.

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Research Paper Composite wood products

The effect of heat treatment on physical and mechanical properties of particleboard produced from orchard trees pruning - industrial wood particles

Morteza Ghanbari; vahid vaziri; Farshid Faraji; loya jamalirad

Volume 40, Issue 2 , May 2025, Pages 124-137

https://doi.org/10.22092/ijwpr.2025.367890.1789

Abstract

Background and objective: Wood, as a natural and renewable material, in addition to its numerous advantages, possess some disadvantages, including its deterioration when exposed to outdoor conditions and its dimensional instability due to fluctuations in relative humidity in the surrounding environment. ... Read More Background and objective: Wood, as a natural and renewable material, in addition to its numerous advantages, possess some disadvantages, including its deterioration when exposed to outdoor conditions and its dimensional instability due to fluctuations in relative humidity in the surrounding environment. Heat treatment can enhance the dimensional stability of panel products, such as particleboard, fiberboard, and OSB. Because heat treatment causes chemical changes in wood, including decrease in hemicellulose and the number of hydroxyl groups. The main objective of this research was to assess the effect of steam pretreatment of orchid tree pruning - wood particles on the physical and mechanical properties of particleboard. Materials and methods: Industrial wood particles from Sanate Choube Shomal Company were used. The ratio of wood chips to orchid tree pruning was used at the level of 70:30. Heat pretreatment was conducted on the wood particles at the temperature of 180 °C with three different retention times (15, 30, and 45 minutes). Urea formaldehyde resin was applied at 10 percent level based on the dry weight of the raw material as well as ammonium chloride was used as a catalyst at a 2 percent level of the dry weight of the adhesive. After the heat treatment and the mixing processes, the raw materials were formed into a mat and then pressed at temperature of 160 °C for 5 minutes. The physical and mechanical properties of the boards were evaluated according to European standards test methods (EN326-1). The analysis of the physical and mechanical properties of the panels were performed using variance analysis at a 95% probability level. Results: The results showed that the boards made from treated particles with a 45-minute treatment duration exhibited the highest bending strength, modulus of elasticity, and internal bonding. Since heat treatment softens and ramified the lignin and increased the crystallization of cellulose, which improves the strength of the board. Thickness swelling and water absorption of the boards were significantly improved with increased treatment duration. The main reason for dimensional stability can be attributed reduction of hemicellulose content and hydroxyl groups within the wood component. Conclusion: Based on the findings of this research, heat treatment significantly improved the dimensional stability of the boards. Bending strength, modulus of elasticity, and internal bonding in the treated samples displayed the highest measured values. In comparison to the properties of the treated boards at 30-minute and 45-minute duration demonstrated the potential to produce particleboards with desirable attributes suitable for interior application (Type P2) for application in dry conditions.

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Research Paper Pulp and paper

Modification of kraft pulp fibers by acid oxidation method

Arman Sadafi Ardejani; Esmaeil Rasooly Garmaroody; Pyam Ghorbannezhad sorkhkolaei

Volume 40, Issue 2 , May 2025, Pages 138-148

https://doi.org/10.22092/ijwpr.2025.367997.1790

Abstract

Background and purpose: Cellulose fiber has an anionic property to some extent due to having acid groups created during the chemical cooking and pulp bleaching. These acid groups may be carboxylic groups (COOH) which have more activity and reactivity compared to the hydroxyl groups present on the carbohydrates ... Read More Background and purpose: Cellulose fiber has an anionic property to some extent due to having acid groups created during the chemical cooking and pulp bleaching. These acid groups may be carboxylic groups (COOH) which have more activity and reactivity compared to the hydroxyl groups present on the carbohydrates of lignocellulosic materials. If it is possible to increase the number of these groups on the fiber surface, it can improve the strength of the final paper. This research was done in order to improve the characteristics of kraft pulp from Chuka pulp and Paper Company by using acid oxidation method with hydrogen peroxide. Materials and methods: In this research, kraft pulp, which was collected from Chuka Company, was used as a raw material. In this regard, first, kraft pulp were subjected to acid oxidation treatment using hydrogen peroxide the rate of 1, 3, 5 and 10% at 85 °C, in 90 min., pH = 4 and consistency of 2.5%. At the end of this step, the pulps were thoroughly washed with distilled water and used for the next steps. Then the structural characteristics of the fibers such as kappa number, WRV, carboxyl groups, viscosity and FT-IR analysis were evaluated and compared with the control sample of Chuka kraft pulp. SPSS software was used for the statistical analysis of this research and the data were statistically analyzed using the analysis of variance technique. The comparison between different samples and treatments was done based on the grouping of averages and by Duncan's test method at a confidence level of 95%. Results: The results showed that the oxidized pulps with up to 3% peroxide consumption had the lowest kappa, carboxyl groups and viscosity and the highest WRV. Increasing the consumption of peroxide the rate of greater than 3% has caused an increase in Kappa number, carboxyl groups and viscosity, and instead they have faced with the decrease in WRV. These changes were also confirmed by FT-IR evaluations. The reason for the decrease in kappa number up to 3% concentration is due to the removal of lignin from the fiber wall, and the reason for its increase in concentrations at more than 3% peroxide, is probably due to the creation of acidic hexuronic groups during the oxidation process, which usually cause errors in the measurement of kappa. In addition, the removal of lignin improved the WRV properties of the fibers and further reduced this property. The content of carboxyl groups for both alkaline and acidic conditions seems to be more or less unchanged, which means that in C6, most aldehydes are converted into carboxyl groups, and in C2 and C3, oxidation often causes the formation of ketones. On the other hand, it seems that increasing the carboxyl groups in treatments above 3% has led to an increase in the molecular weight of cellulose, which has increased the viscosity. Conclusion: The evaluation of the results showed that the oxidation of acidic hydrogen peroxide has modified and improved the characteristics of kraft pulp, and its effects are expected to be positive on the characteristics of the final papers. In this regard, 1% and 3% acid oxidation treatments with hydrogen peroxide seems more suitable for paper production.

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Research Paper Pulp and paper

Investigating the resistance and barrier properties of bio nano composite films of Carboxymethyl chitosan/ Guar gum/ Nanocrystalline cellulose

bardia sodeifi; Seyed Hassan Sharifi

Volume 40, Issue 2 , May 2025, Pages 149-165

https://doi.org/10.22092/ijwpr.2025.368144.1791

Abstract

Background and objectives: The use of polymers with petroleum derivatives in the packaging industry has caused environmental problems due to their non-biodegradability. Development of active and biodegradable packaging is possible by coating biopolymers on packaging materials. In this research, we tried ... Read More Background and objectives: The use of polymers with petroleum derivatives in the packaging industry has caused environmental problems due to their non-biodegradability. Development of active and biodegradable packaging is possible by coating biopolymers on packaging materials. In this research, we tried to use biodegradable materials that are easily decomposed after use in the environment. In this regard, the effect of different treatments with Carboxymethyl chitosan (CMCh), purified Guar gum (PGG) and Nanocrystalline cellulose (NCC) on resistance and barrier properties of paper was evaluated. Methodology: Carboxymethyl chitosan powder and purified Guar gum were dissolved separately in distilled water along with glycerol (40% by weight of biopolymers) as softener. Then the bio composite solutions were heated on a magnetic stirrer for 120 and 90 minutes until the biopolymers were completely dissolved. At the end, they were kept in a static state for 30 minutes to cool down and remove the air bubbles completely. Also, nanocrystal cellulose suspension (3, 6 and 9% based on the weight of biopolymers) was prepared by dissolving in distilled water by ultrasonic device for 3 minutes and then was added to bio composite solution with mixing ratios (30:70, 50:50 and 70:30) and the final suspension was heated on a magnetic stirrer for 120 minutes and it was completely dissolved. Then, in order to cool down and remove the air bubbles completely, it was put in a static state for 30 minutes. At the end, it was centrifuged and let it stand still for 2 minutes to completely remove the air bubbles. Finally, 25 grams of gel was poured into a polystyrene petri dish with a diameter of 10 cm and the petri dishes were placed in an oven at 50 °C for 24 hours. Also, the morphological tests of Carboxymethyl chitosan and bio Nano composite films and the resistance and barrier characteristics of the treatments were studied. Results: The results of measuring the resistance characteristics of biopolymer films showed that with the increase of Nanocrystal cellulose up to the level of 6%, the tensile strength of the treatments increased significantly, and the highest amount was related to the films CMCh/PGG/NCC (50/50/6%). Also, with the increase of cellulose Nanocrystals up to the level of 9% due to the accumulation of Nanocrystal particles in one area, the tensile strength of bio nano composites decreased. Also, due to the origin of its crystallinity, cellulose Nanocrystals led to the brittleness and reduced flexibility of the treatments to reduce the Elongation at break of bio nano composite films. The solubility of bio composite films has decreased by adding NCC to the biopolymer matrix due to the establishment of hydrogen interactions between the components of this matrix with nanoparticles at different levels, and the lowest water Solubility is related to the films CMCh/PGG/NCC (50/50/6%). The water vapor permeability of the treatments decreased by adding NCC to the CMCh/PGG matrix due to reasons such as the crystalline structure and the hydrophobic nature of cellulose fibers, the reduction of pores and the reduction of the diffusion coefficient of vapor molecules, and the best impermeability was obtained by films CMCh/PGG/NCC (50/50/6%) because of uniform dispersion of nanoparticles. Conclusion: According to the results, by adding cellulose Nanocrystals to the composite suspension; Tensile strength, resistance to water solubility and impermeability to water vapor of the films increased and only their Elongation at break decreased and the best resistance and barrier properties of bio nano composites produced in the presence of 6% Nanocrystalline cellulose were obtained.

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Research Paper Pulp and paper

The effect of separate and combined coating of nano graphene-fluorine-zein on the barrier and mechanical properties of brown kraft liner for fruit packaging

Jafar Ebrahimpour Kasmani; Ahmad Samariha

Volume 40, Issue 2 , May 2025, Pages 166-179

https://doi.org/10.22092/ijwpr.2025.367277.1782

Abstract

Background and objectives: Fruit packaging cardboard protects fruits from impacts, pressure, and damage during transportation, while helping to maintain their freshness and quality. To achieve these objectives, it is essential to enhance the strength of the cardboard and minimize the interaction between ... Read More Background and objectives: Fruit packaging cardboard protects fruits from impacts, pressure, and damage during transportation, while helping to maintain their freshness and quality. To achieve these objectives, it is essential to enhance the strength of the cardboard and minimize the interaction between its interior and exterior. At the same time, it must be biodegradable, durable, and environmentally friendly. Kraft paper is recognized as a suitable option for preserving the quality of fruits. Therefore, this research aims to improve the barrier and mechanical properties of cardboard by applying coatings of nano-graphene, fluorine, and zein, both separately and in combination, to provide consumers with higher quality cardboard. Methodology: The brown kraft liner paper with a basis weight of 120 grams was obtained from the Mazandaran Wood and Paper Company. The nanographene type AO-4 was sourced from Graphene Supermarket in the USA, zein protein from Sigma Aldrich, and fluorine from Mine Kavaran Production Group. For coating, the nanographene, zein, and fluorine were weighed in specified weight percentages and mixed with 100 grams of distilled water for 30 minutes at 50 degrees Celsius, 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 added as a retention aid to enhance the coating. The coating solutions were applied to the paper sheets using an Auto Bar Coater (GBC - A4 GIST Co., Ltd). The physical and mechanical properties were measured according to TAPPI and ISO standards. The experimental design was completely randomized, and data analysis was performed using one-way ANOVA and Duncan's test at a 95% confidence level. Results: The one-way ANOVA analysis indicated that there are significant differences at the 5% level among the thickness swelling, water absorption, and porosity of the 8 types of paper. The greatest thickness swelling was observed in the brown liner paper coated with graphene and fluorine, while the lowest thickness swelling was found in the control sample, with a difference of 27% between the maximum and minimum thickness swelling. The lowest water absorption was noted in the brown liner board paper coated with zein, fluorine, and nano-graphene, with a difference of 647.5% between the maximum and minimum water absorption. Additionally, the least porosity was attributed to the paper coated with nano-graphene, showing a difference of 7365.8% between the maximum and minimum porosity. Density analysis revealed that the highest density was observed in the sample coated with zein and nano-graphene, with a difference of 14.5% between the maximum and minimum density. Furthermore, the highest surface smoothness was recorded in the paper coated with nano-graphene and zein, with a difference of 23.9% between the maximum and minimum surface smoothness. For the tensile and tear resistance index, no significant difference was observed at the 5% level, with differences of 15.5% and 26.4% between the maximum and minimum tensile and tear resistance indices, respectively. However, for burst resistance, the lowest value was found in the paper coated with fluorine and zein, with a difference of 14.2% between the maximum and minimum burst resistance. In terms of ring crush test, the highest resistance was related to the paper coated with zein, fluorine, and nano-graphene, with a difference of 16.1% between the maximum and minimum ring crush test. Conclusion: The goal of food packaging is to extend shelf life and protect against spoilage factors. Paper and cardboard, as packaging materials, have specific advantages and disadvantages, including a lack of resistance to moisture. This research addresses the improvement of the physical and mechanical properties of kraft liner paper for fruit packaging and has demonstrated that coating increases thickness swelling and reduces water absorption. These coatings enhance the prevention of water absorption by penetrating the pores of the paper. Various factors affect water permeability, including the paper structure and the type of coating. The use of nano-graphene and zein leads to a reduction in paper porosity and an improvement in its mechanical properties. In this study, coating the paper with nano-graphene and zein significantly increased barrier properties and improved paper quality. Additionally, the results indicate that these compounds can help reduce water absorption and porosity of the paper.

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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.

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

Articles in Press, Accepted Manuscript, Available Online from 28 April 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

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

Articles in Press, Accepted Manuscript, Available Online from 24 May 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

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

Articles in Press, Accepted Manuscript, Available Online from 25 May 2025

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

Abstract

Abstract Background 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 Abstract Background 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

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

Articles in Press, Accepted Manuscript, Available Online from 09 June 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

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

Ramin Vaysi; Hossien Resalati; Rabi Behrooze

Articles in Press, Accepted Manuscript, Available Online from 09 June 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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