Iranian Journal of Wood and Paper Science Research

Public Titles

1404-1

Volume 40, Issue 1 , March 2025

https://doi.org/10.22092/ijwpr.2025.133199

Abstract

Public Titles

Volume 40 Issue 1 spring - Serial Number 90

Volume 40, Issue 1 , March 2025

https://doi.org/10.22092/ijwpr.2025.133173

Abstract

Research Paper Management and Economics wood

Identifying and evaluating criteria for selecting sustainable and resilient suppliers (Case study: Wooden furniture and decoration industry

Shahab Bayatzadeh; Hamidreza Talaie

Volume 40, Issue 1 , March 2025, Pages 1-19

https://doi.org/10.22092/ijwpr.2025.367868.1788

Abstract

Background and Objectives: The wood industry, especially in the furniture and decoration sectors, is one of the small industries with high entrepreneurial potential that faces numerous challenges in the field of sustainability and resilience due to irresponsible exploitation. The aim of this study is ... Read More Background and Objectives: The wood industry, especially in the furniture and decoration sectors, is one of the small industries with high entrepreneurial potential that faces numerous challenges in the field of sustainability and resilience due to irresponsible exploitation. The aim of this study is to identify and prioritize criteria for selecting sustainable and resilient suppliers in the Iranian furniture and decoration industry to help reduce environmental impacts, increase productivity, and ensure the continuity of resource supply through improving supply chain performance. This study is designed to fill the scientific gaps in the comprehensive assessment of suppliers in this industry.Methodology: This research was conducted to identify and prioritize criteria for selecting sustainable and resilient suppliers in the furniture and decoration industry. The research method was designed analytically and applied with a descriptive-survey approach. First, through a comprehensive review of the research literature, the primary criteria related to supplier selection were identified. These criteria were placed in four main categories: economic, environmental, social, and resilience, and included 17 criteria. In order to verify the identified criteria, the fuzzy Delphi method was used. A questionnaire based on the identified criteria was prepared and distributed among 10 experts in the furniture and decoration industry, including supply chain managers and environmental specialists. The experts were selected based on at least 15 years of work experience and familiarity with the principles of sustainability and resilience. The questionnaires were analyzed in two stages, and the third stage was stopped due to the reduction of the difference in opinions between the responses to less than 0.2. For weighing the criteria, the fuzzy Best-Worst Method (FBWM) was applied. This method calculates the weight of each criterion by selecting the most important and least important criteria and conducting pairwise comparisons. The model was solved using LINGO software, and the final ranking of the criteria was extracted. This method, aiming to reduce subjective errors and manage uncertainties in the data, provides an appropriate approach for prioritization in complex environments like the wood industry.Results: The results showed that resilience-related and environmental criteria hold higher importance compared to economic and social criteria. This prioritization highlights the crucial role of these two categories in managing the wood supply chain, especially in dealing with disruptions and ensuring the sustainability of natural resources. The criteria examined included Risk Awareness, Sustainable Resource Use, Supply Chain Flexibility, Recovery Capability, Pollution Control, Cost Efficiency, Delivery Timeliness, Worker Safety, Responsiveness, Quality, Environmental Certifications, Community Impact, Financial Stability, Supplier Relationship, Geographical Location, Technology, and Reputation. Risk Awareness (0.171) and Sustainable Resource Use (0.123) were identified as the most significant factors. Supply Chain Flexibility and Recovery Capability also ranked highly. In the economic category, Cost Efficiency and Delivery Timeliness were the most important criteria. Social criteria such as Worker Safety and Community Impact ranked lower, while Supplier Relationship and Reputation received the least importance. These findings emphasize the wood industry’s focus on resilience and environmental protection, with economic and social criteria considered as supporting factors in later priorities.Conclusion: The findings indicate that in an industry like wood, resilience and environmental sustainability play a key role in supplier selection. This research provides a framework that can assist managers in conducting comprehensive supplier evaluations and making optimal decisions to ensure the continuity of the supply chain and reduce environmental impacts. Future research can further explore global and regional conditions to develop more dynamic models for evaluation.

Research Paper Chemical conversion

Fabrication of Nanocellulosic biosensor as an indicator of meat spoilage

Ali Ghasemi Chahardehi; Ghasem Asadpour; Sead Majid zabihzadeh; Esmaeil Rasooly Garmaroody

Volume 40, Issue 1 , March 2025, Pages 20-34

https://doi.org/10.22092/ijwpr.2025.367510.1786

Abstract

Background and purpose: The annual amount of food waste includes about one third of the global production of edible food. One of the main causes of meat waste is the disease caused by microorganisms. Using continuous and real-time tracking of food spoilage, waste can be significantly reduced. One of ... Read More Background and purpose: The annual amount of food waste includes about one third of the global production of edible food. One of the main causes of meat waste is the disease caused by microorganisms. Using continuous and real-time tracking of food spoilage, waste can be significantly reduced. One of the main ways to identify the change in the quality of the food inside the package is the change in pH. by employing natural polymers containing pH-sensitive substances, it is possible to know the condition of the meat inside the package. Anthocyanins are natural substances sensitive to pH. This research investigated the use of eggplant peel extract to make a pH-sensitive Nanocellulosic biofilm as an indicator of meat spoilage inside the package.Materials and methods: Eggplant peel, after crushing and passing through a sieve, was subjected to extraction in two separate methods (with and without formic acid). The amount of anthocyanin in each method was investigated and then the appropriate extraction method was selected based on the amount of anthocyanin obtained. The resulting anthocyanin, as the main substance sensitive to pH changes, was used in different percentages until the desired result was reached, to make nanocellulose film. In the production of nanocellulose film, anthocyanin was stabilized with the help of two types of cross-linking polymers, namely Penta sodium triphosphate and polyvinyl alcohol, in two separate paths, inside the nanofibrocellulose film, by casting method, at a temperature of 38̊Ϲ for 72 hours in an oven. The resulting film, as an indicator of meat spoilage, was placed inside the packaging of meat products. Some of the mentioned packages were kept at room temperature for three days and some others were kept in the refrigerator for seven days. The change in color of the films was evident in both cases, which indicated the microbial contamination of the meat.Result: The results showed that the amount of anthocyanin in the extraction method with formic acid is twice that of the extraction method without it. The L a b test related to Nanocellulosic films showed that the b factor increased three and a half times in the films inside the package after spoilage the meat. Examination of the films with XRD showed that the addition of the binding polymer as well as the extract increases the degree of crystallinity of the nanocellulose film. Also, the results of FTIR showed that by adding binding polymers, new functional groups are created in the nanocellulose film, before and after being placed inside the packaging.Conclusion: In this research, eggplant peel extract was used to make pH-sensitive nanocellulose film. In terms of anthocyanin content, the method with formic acid was superior to the method without it. Nanocellulose film, in the vicinity of rotten meat, changed color and became greenish yellow. The results show an increase in the degree of crystallinity due to the interaction between the components of the film. The extract itself also turned red in acidic pH and greenish-brown in alkaline pH. Finally, it was found that by using the visible color change of the aforementioned biodegradable nanocellulose film, it is possible to visually know the condition of the food inside the package.

Mechanical conversion of wood and wooden fittings Mechanical conversion of wood and wooden fittings

Improving the performance of polyvinyl acetate adhesive in order to increase the strength and stability of tongue and groove joints in traditional beech wood structures

Vahid Sokhandan; Hamidreza Mansouri; Mohammad Dahmardeh Ghaleno; Mohammad Shamsian

Volume 40, Issue 1 , March 2025, Pages 35-53

https://doi.org/10.22092/ijwpr.2025.366640.1778

Abstract

Background and Objectives: Historical wooden constructions clearly depict the identity, architecture, culture and lifestyle of the people of a period of history and are available to future generations as precious treasures. Therefore, the disconnection of the joints of historical wooden constructions ... Read More Background and Objectives: Historical wooden constructions clearly depict the identity, architecture, culture and lifestyle of the people of a period of history and are available to future generations as precious treasures. Therefore, the disconnection of the joints of historical wooden constructions is a big problem to preserve these valuable works in the long term. This research was carried out with the aim of improving and strengthening polyvinyl acetate (PVAc) adhesive using using nanocellulose fibers (NFC) and glass nanofibers (GNF) to improve the joints of the tongue and groove in the traditional beech wood constructions.Materials and methods: In this research, in order to study the effects of reinforcements on the properties of PVAc adhesive, NFC and GNF were investigated at three different levels including 0, 3, and 6% based on the dry weight of the adhesive (9 treatments; each treatment with 3 repetitions). The connection of the palate and the tongue using polyvinyl acetate glue without NFC and GNF were considered as control samples. After preparing the samples, quantitative and qualitative tests including tensile strength, bending strength (modulus of rupture and modulus of elasticity), accelerated aging test, FTIR spectroscopy and evaluation of the samples using electron microscope scanning (SEM) was done.Results: According to the results, there was a significant difference between the studied treatments in terms of tensile strength and modulus of rupture and modulus of elasticity (P<0.05). Among the examined treatments, the highest amount of tensile strength (13.9 MPa), modulus of rupture (130.5 MPa) and modulus of elasticity (11785.36 MPa) were observed in PVAc treatment modified with 3% CNF and 3% GNF. In addition, the results showed a significant difference between the treatments in terms of accelerated aging rate (P<0.05). The lowest rate of accelerated aging (4.0) was observed in PVAc treatment modified with 3% NFC and 3% GNF. FTIR spectroscopy showed that when CNFs are inserted into the PVAc polymer matrix, hydrogen bonds are formed between the hydroxyl groups (OH) of polymer chains and the hydroxyl groups of nanocellulose, which causes the formation of coherent three-dimensional networks. Also, according to the observations from scanning electron microscope (SEM), it was found that CNFs and GNFs were relatively well dispersed in the PVAc polymer matrix.Conclusion: This study showed that by adding 3% NFC and 3% GNF to PVAc adhesive, the mechanical properties of joints in beech wood structures increase. Considering this issue, it is recommended to use a combination of cellulose nanofibers (NFC) and glass nanofibers (GNF) in order to improve the resistance properties of joints in traditional wooden structures.

Pulp and Paper Nano composite

Investigation of the use of carboxymethylcellulose-based magnetic biocomposite in paper coating

Shaghaiegh Rezanezhad; Noureddin Nazarnezhad; Hosein Resalati; Seyed Majid Zabihzadeh

Volume 40, Issue 1 , March 2025, Pages 54-66

https://doi.org/10.22092/ijwpr.2025.367727.1787

Abstract

Background and objectives: Carboxy methyl cellulose (CMC) is one the ether derivatives of cellulose and is widely used in various industries. This material is one of the most important and widely used cellulose derivatives, which has been considered in many researches as a substrate for the production ... Read More Background and objectives: Carboxy methyl cellulose (CMC) is one the ether derivatives of cellulose and is widely used in various industries. This material is one of the most important and widely used cellulose derivatives, which has been considered in many researches as a substrate for the production of composite materials due to the presence of the carboxy methyl and hydroxyl groups. CMC can also be used as a substrate for the production of the magnetic cellulose compounds. Magnetic materials such as iron oxide are able to form effective bonds with hydroxyl groups in CMC and produce magnetic composites with biodegradable properties. The purpose of this research is to produce and analyze the magnetic properties of biocomposite made from CMC and then coat it on the surface of paper.Methodology: In this research, CMC was used as a substrate for the production of magnetic biocomposite. The in-situ synthesis was used to produce biocomposite. In the process, iron salts (4 and 6 H2O) and CMC were mixed together in an aqueous solution and under nitrogen atmosphere, then by adding ammonium hydroxide to pH 11, iron oxide particles (magnetite) were formed on CMC. The materials were stirred in water bath for 1 hour at 40 °C, in order to complete the reactions and increase the production efficiency of magnetic particles. Handsheets with 120 ± 5 g/m2 weight was prepared by using commercial kraft fibers, and then coated with magnetic biocomposite. The synthesized magnetic materials and coated paper with magnetic biocomposite were analyzed by X-ray diffraction. The size of iron oxide was tested by an atomic force microscope. Also, the morphology and surface characteristics of magnetic particles, magnetic biocomposite and coated fibers and paper were investigated by scanning electron microscope. The magnetic properties of the samples were evaluated with a vibrating magnetometer. Furthermore, the strengths properties of the coated paper were examined with tensile, tear, water absorption and air resistance tests.Results: The results of the magnetic test showed that in the first phase, the magnetic biocomposite was successfully prepared and the sample showed super paramagnetic properties. The highest magnetic saturation in the iron oxide sample was about 25 emu/g. Also, the CMC magnetic biocomposite had a magnetic saturation about 4 emu/g. The results of the microscopic evaluation of the iron oxide particles showed a uniform cubic structure. The formation of this structure is due to the accumulation of particles. In addition, mechanical engagement and connection of the magnetic biocomposite with the paper was observed. Also, the microscopic analyze of the iron oxide showed the most frequent of particles size were 45 nm. The results of the strength properties of the paper showed that the coating with magnetic material decreased the tensile and tear indices. The air resistance in the coated paper samples has increased compared to the control sample. Based on the results of Cobb test (water absorption), the lowest water absorption is related to the coated paper with CMC magnetic biocomposite. The X-ray diffraction pattern of the iron oxide sample showed five important peaks at 2 theta angles of 35, 41, 50, 67 and 74 degrees, which the main peaks indicated the iron oxide.Conclusion: The purpose of this research was to analyze the magnetic property in the CMC biocomposite and then coat it on the surface of the paper. Therefore, the experiments were carried out in 2 stages. In the first stage, CMC magnetic biocomposite was made by in situ synthesis process with iron salts. In the second phase, handsheet was prepared by using commercial kraft fibers and coated ones. The results of the testing samples showed the successfully production of magnetic biocomposite. Also, the paper coated with this material has suitable magnetic properties.

Research Paper Pulp and paper

The effect of fiber oxidation on the properties of corrugated paperboard

Esmaeil Rasooly Garmaroody; Omid Esmaeili; Sead Rahman jafari Petrody

Volume 40, Issue 1 , March 2025, Pages 67-80

https://doi.org/10.22092/ijwpr.2025.367374.1784

Abstract

Background and purpose: Paying attention to the resistance properties of paper during its production and consumption has always been particularly fashionable for paper makers. In the case of NSSC pulp, it is very important to maintain its resistance and continuous production for the production of floating ... Read More Background and purpose: Paying attention to the resistance properties of paper during its production and consumption has always been particularly fashionable for paper makers. In the case of NSSC pulp, it is very important to maintain its resistance and continuous production for the production of floating papers or the combination in the production of various types of liner paper. The use of recycled papers in pure form or in combination with virgin papers has shown that the resistance properties of the resulting papers are reduced. Therefore, in order to use recycled paper, either pure or combined with virgin pulp, it is necessary to take measures to improve the quality of the final paper.Materials and methods: This research was conducted to investigate the effects of using oxidation methods with hydrogen peroxide and hypochlorite to monitor the characteristics of congress corrugated pulp by combining NSSC and OCC pulps. In this research, firstly, the desired pulps were oxidized using hydrogen peroxide and sodium hypochlorite in different proportions, and then according to the TAPPI standard, handmade papers of 127 g/cm2 were made from them. Finally, the mentioned papers in terms of physical characteristics such as Cobb-60 and Air resistance; And the mechanical strength were evaluatedResults: The control treatments have more water absorption resistance and its amount decreases with the oxidation treatment of the pulps. Papers obtained from pulps oxidized with hypochlorite have more resistance to air passage than with peroxide. In this sense, the paper obtained from pure OCC treatment has the lowest air resistance. Papers obtained from pulps oxidized with peroxide have more tear index. Therefore, it seems that peroxide is preferred in terms of tearing properties compared to hypochlorite. In most cases, papers obtained from hypochlorite treatment have more tensile index. The use of oxidation with hypochlorite increases the forld resistance. In terms of CMT, RCT and CCT resistances, combined oxidation processes have been more effective, especially in treatments containing long fibers. The effect of oxidation with peroxide and hypochlorite on the resistance of the paper surface in NSSC and OCC papers are completely different and act in the opposite direction. But in combined treatments, more CMT is obtained. The effect of both oxidants on the characteristics of resistance to ring crushing (RCT) in NSSC and OCC papers in pure treatments has an upward trend, and in the combined state, it causes a decrease in RCT in the papers. The effect of oxidation with hypochlorite on the paper edge cramp resistance (CCT) has been higher compared to peroxideConclusion: The use of oxidation treatment with peroxide for all pulps makes the resulting papers have a higher tearing index. However, in the use of hypochlorite, the resistance characteristics affected by the bond between fibers, such as tensile strength and folding resistance, have been improved. In terms of resistance characteristics such as CMT, RCT and CCT resistance, the combination of peroxide and hypochlorite treatments along with long fibers have been more effective, therefore, considering the importance of these characteristics in the production of congress paper, it is suggested that these treatments should be prioritized.

Research Paper Chemistry of wood

Evaluation of antioxidant properties of extracts from the heartwood and sapwood of Melia azedarach

Maryam Ahmadi; Seyed Majid Zabihzadeh; Noureddin Nazarnezhad; Ghasem Asadpour; Pourya Biparva

Volume 40, Issue 1 , March 2025, Pages 81-94

https://doi.org/10.22092/ijwpr.2025.368212.1793

Abstract

Background and objectives: Plant extracts contain antioxidant compounds, which have garnered increasing attention in various scientific and industrial fields due to their significance. Among the most important groups of compounds present in plant extracts are phenolic compounds. These compounds not only ... Read More Background and objectives: Plant extracts contain antioxidant compounds, which have garnered increasing attention in various scientific and industrial fields due to their significance. Among the most important groups of compounds present in plant extracts are phenolic compounds. These compounds not only possess antioxidant properties but also have diverse applications in various industries. Numerous plants have been investigated for the extraction of bioactive compounds. Chinaberry (Melia azedarach), a woody species, is known to contain antioxidant substances. In this study, the extracts from heartwood and sapwood of chinaberry were obtained, and the extracted compounds were identified. Additionally, the antioxidant properties of these compounds were evaluated. This research provides valuable insights into the potential applications of antioxidant compounds derived from chinaberry in different industries.Methodology: First, the heartwood and sapwood of Melia azedarach (chinaberry) were separated and ground using a laboratory mill. Particles of size 60 mesh were isolated using a laboratory sieve. Prior to extraction, the wood flour underwent pre-extraction with hexane. Three different extraction methods were employed: Soxhlet, immersion, and ultrasonic. In all methods, 10 grams of wood flour were used as the raw material. In the Soxhlet method, the raw material was placed in a thimble and then the thimble contain wood flour transferred to a flask containing 250 mL of ethanol. The Soxhlet system was set up, and after the first siphoning, the samples were heated for 6 hours to complete the extraction process. In the immersion method, the samples were stirred with 250 mL of ethanol at 40°C for 24 hours using a magnetic stirrer. In the ultrasonic method, the wood flour was combined with 100 mL of ethanol in a beaker. The resulting mixture was treated at 40°C for a total of 6 minutes, divided into two 3-minute intervals, using ultrasonic waves at a frequency of 20 kHz and an amplitude of 50%. The compounds present in the extracts obtained from all three methods were identified using GC-MS analysis. The total phenolic and flavonoid content of the extracts was quantified. Additionally, the antioxidant activity of the extracts was evaluated using the DPPH method.Results: The analysis of extractable content before pre-extraction with hexane revealed that the heartwood contained a higher number of extractable materials compared to the sapwood. Following extraction using three different methods, a re-assessment of extractable content indicated that the highest amount was obtained from the sapwood using the Soxhlet method. GC-MS analysis of extracts derived from the heartwood and sapwood of Melia azedarach showed that methoxyphenol was the predominant phenolic compound identified in both wood types when extracted using the Soxhlet method. In the immersion method, beta-sitosterol was the most abundant compound in the heartwood, while methylphenol dominated in the sapwood. For the ultrasonic method, imidazolidinedione was the most abundant compound in the heartwood, and beta-sitosterol prevailed in the sapwood. The highest phenolic compound content was observed in the sapwood extract obtained using the Soxhlet method, measuring 0.45865 µg gallic acid per mg of extract. The maximum flavonoid content was also recorded in the sapwood extract from the Soxhlet method, with 0.493172 mg quercetin per gram of dry weight. Antioxidant activity assessment demonstrated that the extract obtained from the heartwood using the immersion method exhibited the highest antioxidant activity.Conclusion: This study aimed to investigate the extraction of heartwood and sapwood from Melia azedarach and evaluate the impact of three different extraction methods- soxhlet, immersion, and ultrasonic- on the yield of the extracted materials. Additionally, the antioxidant properties of the extracts obtained through these methods were assessed. The results revealed that phenolic compounds constituted the majority of the extracted materials in both heartwood and sapwood extracts of this species. The soxhlet method demonstrated the highest efficiency in extracting phenolic and flavonoid compounds from the sapwood, while the immersion method exhibited the highest antioxidant activity in the extracts obtained from the heartwood. These findings underscore the influence of the extraction method on the quantity and type of compounds extracted as well as their antioxidant properties. This study provides valuable insights into the potential utilization of antioxidant compounds in industrial and pharmaceutical applications.

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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