Mechanical conversion of wood and wooden fittings
Vahid Sokhandan; Hamidreza Mansouri; Mohammad Dahmardeh Ghaleno; Mohammad Shamsian
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 ...
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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.
Composite wood products
Javad Torkaman; rouzbeh asadi khansari
Abstract
Fibre-gypsum board is a composite, in which fiber used as the reinforcement in the matrix of gypsum. The purpose of this article is to investigate the effect of different amounts of waste paper fibers on the strength, resistance and the fracture behavior of fiber-gypsum board. For this purpose, amounts ...
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Fibre-gypsum board is a composite, in which fiber used as the reinforcement in the matrix of gypsum. The purpose of this article is to investigate the effect of different amounts of waste paper fibers on the strength, resistance and the fracture behavior of fiber-gypsum board. For this purpose, amounts of zero, 5, 10, 15, 20, 25 and 35 percent of waste paper fibers have been used. The results of measuring bending strength, internal bonding and moisture absorption during one month exposure to 100% relative humidity show that increasing the percentage of fibers up to 20% has increased the mechanical properties. In general, By using twenty percent fibers the bending strength increased fifty percent and the internal bonding became double and half in comparison to the control samples. The load-displacement curve shows that an increase of 5 to 15 percent of fibers does not change the fracture behavior of the fiber-gypsum board and they had brittle fracture same as control samples. While in more substitution values, the flexibility increases and the failure becomes ductile. Therefore, the best conditions in terms of strength, resistance, and flexibility have been obtained in 20% replacement of gypsum with waste paper fibers.
Composite wood products
Reza Jazayeri; Saeed Kazemi Najafi; Habibollah Younesi
Abstract
This study aimet at to use modified graphite materials as a multifunction additive in the UF resin for improving the properties of medium density fiberboard (MDF). For this purpose expanded graphite EG was synthesized from graphite using the Tsai et al (2011) method. Then, as-synthesized EG was intercalated ...
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This study aimet at to use modified graphite materials as a multifunction additive in the UF resin for improving the properties of medium density fiberboard (MDF). For this purpose expanded graphite EG was synthesized from graphite using the Tsai et al (2011) method. Then, as-synthesized EG was intercalated with manganese dioxide by Schwarz et al (1995) method and converted to MnO2-EG. Any additive was added to the urea formaldehyde resin in three doses of 1, 2 and 3% to make the relevant MDF panels with 750 kg/m3 nominal density. During the pressing time, the tT100oc parameter (time to reach temperature100○C) of the middle layer of the board under the influence of the additive was determined by a chromium-nickel-based thermocouple. The treatment of MnO2-EG3 (amount of 3% modified expanded graphite) showed the greatest effect in reducing tT100°C of the middle layer of the board by 22%. In addition, the elastic modulus increased by 68% as a result of this treatment. In addition, the elastic modulus increased by 68% as a result of this treatment. G and EG additives showed a higher degree of internal adhesion than that of MnO2-EG additive. In this regard, EG2 and EG3 treatments showed a 42% increase in internal adhesion and G2 treatment showed a 40% increase in internal adhesion. The effect of EG2 treatment in improving SW24 was greater than other treatments, so that it caused a 19% decrease compared to the control.
Aliakbar Yazdi meymand; Ali Khaki; mohammad ghofrani
Abstract
Sandwich panels are one of the most advanced forms of composite structures that are widely used. The objective of this study was to investigate the effect of three types of resin: urea formaldehyde (UF), melamine formaldehyde (MF) and the combination of urea formaldehyde + melamine formaldehyde (UF + ...
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Sandwich panels are one of the most advanced forms of composite structures that are widely used. The objective of this study was to investigate the effect of three types of resin: urea formaldehyde (UF), melamine formaldehyde (MF) and the combination of urea formaldehyde + melamine formaldehyde (UF + MF) two core layer densities (400 and 500 kg/m3) on physical and mechanical properties of sandwich panels made of palm leaves waste. Pressure temperature, pressure and time for all panels were 175 °C, 35 kg /cm2 and 9 minutes, respectively. The final thickness of all panels was the same and equal to 25 mm. Physical and mechanical properties include; Water absorption (WA), thickness swelling (TS), modulus of rupture (MOR), modulus of elasticity (MOE), impact bending strength (IBS) and internal bonding (IB) were performed on the samples. The results showed that there was a significant (p<0.05) difference between the values of different treatments at the level of 95%. Physical properties (except thickness swelling) and mechanical properties with a density of 500 kg/m3 improved. The use of MF and UF + MF resins significantly improved the physical and mechanical properties of sandwich panels due to its high adhesive quality.
soheila izadyar; Roghayeh Hamzezadeh; Davood Efhamisisi
Abstract
The aim of this study was to investigate the effect of poplar wood saturation with nano-wollastonite and nano-wollastonite-styrene mixture on fire resistance and mechanical properties of polymer wood. Populus deltoids with 4% nano-wollastonite and 75% methanolic solution of styrene monomer was saturated ...
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The aim of this study was to investigate the effect of poplar wood saturation with nano-wollastonite and nano-wollastonite-styrene mixture on fire resistance and mechanical properties of polymer wood. Populus deltoids with 4% nano-wollastonite and 75% methanolic solution of styrene monomer was saturated by vacuum-pressure method. Four different wood treatments with nano-wollastonite, styrene, simultaneous nano-wollastonite and styrene (one-step) by 1:1 ratio and finally, the initial wood saturation by nano-wollastonite and then styrene (two-stage treatment) were investigated. In this study, the fire resistance and mechanical properties of the specimens were investigated. The results showed that the weight loss of wood against fire in two-stage treatment (NW+St) was 61.38% and in one-stage treatment (NW/St) was 69.68% better than control. NW/St treatment flame durability was approximately equal to NW treatment and improved by 30% compared to control. The reduction of carbonized area in two-stage (NW+St) and one-stage (NW/St) treatments was 28.53% and 29.06%, respectively, which showed a significant decrease. The results of mechanical tests showed that the NW/St treatment had the highest value due to the presence of condensing material in parallel to the NW/St treatment which showed an increase of 57.41% compared to the control sample. The modulus of elasticity and disruption of NW/St treatment increased by 26.77% and 35.71%, respectively. In addition, resistance to hardness of NW/St treatment increased by 10.07% compared to control. Overall, it can be concluded that mixing nano-wollastonite with styrene, while increasing the polymer wood fire resistance, also improved the mechanical properties of the polymer wood.
Composite wood products
Leila Fathi; Mohammad mehdi Faezipoor; Mohsen Bahmani
Abstract
In this investigation the effect of using of UF and MUF Resins on Physical and mechanical Properties of Particleboards Produced from Rice Straw and Aspen Particles has been studied. The aim of this study was to determine of physical and mechanical properties of rice straw– particleboard. ...
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In this investigation the effect of using of UF and MUF Resins on Physical and mechanical Properties of Particleboards Produced from Rice Straw and Aspen Particles has been studied. The aim of this study was to determine of physical and mechanical properties of rice straw– particleboard. Single-layer particleboard was produced. That was produced with 11% MUF and 11% UF. For using of UF and MUF 2% hardener was added to adhesives. The Press condition for MUF was: 1750C for 4 minutes and also for UF application was 1750C for 6 minutes. Another variable factor was the rice straw content in three levels (15%, 30% and 45%). Other factors such as board density (0/7gr/cm3), mat moisture (12%) were constant factors. The results indicate that increasing rice straw to wood particles cause some reduction in modulus of rupture , and internal bonding , and some increase in thickness swelling , and water absorption of manufactured boards. But comparing and grouping means by Duncan test showed that in the most case these effects were insignificant when rice straw add to wood particle up to 30%. Particleboard bonded with 11% MUF had the highest bending strength. Particleboards bonded with MUF had better bending strength, shear strength, thickness swelling and water absorption after 2, 24 hours immersion. Grouping the experimental data while using Duncan method was indicated of the fact that an optimum condition for manufacturing particleboard while using a mixture of rice straw and wood particles is to add 30% rice straw to the mixture , use 11% melamine urea formaldehyde resin and employ a pressing time of 4 minutes.
Composite wood products
Amir Nourbakhsh
Abstract
In this research was to use the effects micro cellulose, and Multi walled Carbon Nanotube on the mechanical properties of wood plastics composites. This article presents the application of Multi walled Carbon Nanotube in order to evaluate and compare their suitability as reinforcement for thermoplastics. ...
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In this research was to use the effects micro cellulose, and Multi walled Carbon Nanotube on the mechanical properties of wood plastics composites. This article presents the application of Multi walled Carbon Nanotube in order to evaluate and compare their suitability as reinforcement for thermoplastics. The effects of loading micro cellulose and Multi walled Carbon Nanotube content on the mechanical properties were also studied. The results showed that mechanical properties of the composites made with 50 micron cellulose and 1.5 and 2.5 % of Multi walled Carbon Nanotube were significantly superior to those of the lower length (20 micron) and control samples. Addition of Multi walled Carbon Nanotube could enhance the mechanical properties of the blends, due to the improvement of interface bond between the filler and matrix of wood plastics composites. The significant improvements in mechanical properties of the blends composites made with Multi walled Carbon Nanotube and micro cellulose were further supported by SEM and TEM micrographs.
Composite wood products
Mohammad Zafari sarmori; saeid reza Farokhpayam; Ehsan Sanei; mohammad shamsian
Abstract
Although many studies have been done about the application of waste materials such as used plastics but returning of wood plastic products (Regrind) to the production cycle was rarely reported. In this work, the effect of once and twice regrind on the functional properties of WPC made from high density ...
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Although many studies have been done about the application of waste materials such as used plastics but returning of wood plastic products (Regrind) to the production cycle was rarely reported. In this work, the effect of once and twice regrind on the functional properties of WPC made from high density polyethylene (HDPE) has been studied. The specimens were fabricated with powder raw materials and by the flat press under laboratory conditions. HDEP and poplar wood flour were mixed with a weight ratio of 50-50 percent. The estimation of regrind process, physical and mechanical properties of boards were measured after each regrinding and also to evaluate of regrinding on filler particle size and the interface between the polymer and wood flour some Scanning Electron Microscopy (SEM) were prepared. The results of this research showed that regrinding of WPC leads to a decrease in mechanical properties including bending strength, flexural modulus, tensile strength and tensile modulus and on the other hand regrinding process leads to improved physical properties including water absorption and thickness swelling after hours. SEM photographs showed that during the process of regrinding, filler particle size is reduced while matrix surrounding the filler particles better.
Composite wood products
Abolfazl Kargarfard
Abstract
Investigation on the Effect of Resin Gradient Consumption on Particleboard Properties Made Using Rose Flower Stalks Residues Abolfazl Kargarfard *Associate Prof., Wood and Paper Science and technology Research Division, Research Institute of Forests and rangeland, Tehran, Iran, kargarfard@rifr-ac.irAbstractThe ...
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Investigation on the Effect of Resin Gradient Consumption on Particleboard Properties Made Using Rose Flower Stalks Residues Abolfazl Kargarfard *Associate Prof., Wood and Paper Science and technology Research Division, Research Institute of Forests and rangeland, Tehran, Iran, kargarfard@rifr-ac.irAbstractThe potential of rose flower stalks for the production of particleboard was investigated. Three resin dosage gradients of 0, 2 and 4% (10% core: 10% surface; 9%core:11% surface and 8% core:12% surface) and three press times (3, 4 and 5 minutes) were selected as the variables and boards were produced. Then the mechanical and physical properties of the boards were measured and statistically analyzed. The results of modulus of rupture (MOR), modulus of elasticity (MOE) and internal bonding (IB) measurements showed that as the resin dosage gradient increases, these properties improved and boards produced using either 2 or 4% resin dosage gradients generated the highest values. The effect of resin dosage gradient on these properties was statistically significant. As the resin dosage gradient increases, both thickness swelling after 2 and 24 hours immersion in water was improved. The effect of press time on thickness swelling after 2 and 24 hours immersion in water was also statistically significant and these properties were improved when 5 minutes press time was used The results indicate that if 2 or 4% resin dosage gradients and either 4 or 5 minutes press time is applied for the manufacturing of particleboards using rose flower stalks residues, the specification of the boards will meet the EN specification.Keywords: Particleboard, Rose flower stalks, Resin dosage gradient, Mechanical Properties, Physical Properties
Management and Economics wood
Elham Hatamzadeh Arabi; Maryam Ghorbani; Prya Biparva
Abstract
The current research work was planned to investigate the possibility of zinc oxide nanoparticles synthesis using hydrothermal method in wood structure and its effect on mechanical and biological properties of wood-polymer composite. Test samples were divided to control and treated with styrene, zinc ...
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The current research work was planned to investigate the possibility of zinc oxide nanoparticles synthesis using hydrothermal method in wood structure and its effect on mechanical and biological properties of wood-polymer composite. Test samples were divided to control and treated with styrene, zinc oxide nanoparticles, nanocomposite and nano/Styrene. Mechanical and biological tests samples according toASTM-D143 and EN113 respectively were treated by vacuum- pressure method using cylinder experimental. The mechanical tests were considered for each level 5 repeat and for biological test for each level 10 repeat. The presence of zinc oxide nanoparticles on cell wall and styrene in the cell cavities were confirmed by Scanning electron microscopy. According to the results, bending strength, bending modulus, hardness and pressure parallel to grain for nano/styrene samples with highest improvement were increased 36.74, 40.23, 60.58 and 25.07 in comparison with control respectively. Also, decay resistance of treated samples increased, so that maximum and least weight loss were recorded for control and nano/styrene samples with 25.81 and 3.37% weight loss.
Management and Economics wood
Neda Esmaeili; Maryam Ghorbani; Porya Biparva
Abstract
In this study, the mechanical and biological properties of modified poplar wood with glutaraldehyde and paraffin were investigated. Modification was performed with glutaraldehyde at different concentrations of glutaraldehyde, 5, 10 and 20% using magnesium chloride as a catalyst and then subsequently ...
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In this study, the mechanical and biological properties of modified poplar wood with glutaraldehyde and paraffin were investigated. Modification was performed with glutaraldehyde at different concentrations of glutaraldehyde, 5, 10 and 20% using magnesium chloride as a catalyst and then subsequently with paraffin by vacuum-pressure method. Increasing concentration of glutaraldehyde caused to weight gain and bulking wood cell wall, subsequently reduced paraffin penetration into the porous structure of wood. Biological resistance exposed to white rot fungi and mechanical properties were measured according to the standards EN113 and ASTM D143-94, respectively. Scanning electron microscopic images showed bulking of cell walls and paraffin presence in cell cavities. According to results of TGA, increasing of modification intensity decreased mass loss due to cross linking formation between glutaraldehyde and cell wall polymers. Paraffin at combined modification containing 10% and 20% glutaraldehyde improved significantly the modulus of elasticity. Glutaraldehyde reduced bending strength, but paraffin present in the modified samples improved it. The Glutaraldehyde increased compression strength parallel to grain and hardness that the improvement was more obvious in combined modification. Modification with glutaraldehyde enhanced decay resistance exposed to white rot fungi, and this improvement intensified at the presence of paraffin. Inhibitory influence of chemical modification on wood attacking white rot fungi can be attributed to decreases the wood moisture, bulking of cell walls and blocking cell cavities.
Composite wood products
Amir Norbakhsh; Abolfazl Kargarfard
Abstract
In this research the impact of micro cellulose particles length, and coupling agent (MAPP) on the mechanical and thermal properties of Nano/ wood plastics composites were investigated. The results showed that mechanical properties of the composites made with 50 micron micro cellulose particles and 5 ...
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In this research the impact of micro cellulose particles length, and coupling agent (MAPP) on the mechanical and thermal properties of Nano/ wood plastics composites were investigated. The results showed that mechanical properties of the composites made with 50 micron micro cellulose particles and 5 % of MAPP were significantly different to those of the lower length (20 micron) and 2.5% of MAPP. Addition of MAPP enhanced the mechanical and thermal properties of the blends, due to the improvement of interface bond between the filler and matrix of Nano/ wood plastics composites. The significant improvements in mechanical properties of the blended composites made with MAPP and NC were further supported by SEM and TEM micrographs. Nano/ clay particles distribution and thermo gravimetric analysis (TGA) indicated that the addition of 5% MAPP and the longer micro cellulose particles remarkably increased the thermal stability of the blends compared to other treatments of Nano/ wood plastics composites.
Pulp and paper
Saleh Ghahrmani; Sahab Hejazi; Saeid Mahdavi
Abstract
In this research, capacity of cellulose nanofibers to reinforce of high yield kraft pulp produced (HYKP) from Populus deltoides clone 69-55 for making unbleached top kraft liner (UTKL) was investigated. The variable conditions of cooking were included the cooking time and temperature each one in two ...
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In this research, capacity of cellulose nanofibers to reinforce of high yield kraft pulp produced (HYKP) from Populus deltoides clone 69-55 for making unbleached top kraft liner (UTKL) was investigated. The variable conditions of cooking were included the cooking time and temperature each one in two levels. Sulfidity and active alkali were constant in the all cooking and liquid to wood ratio was 4 to 1. Optimum pulp was selected according to the pulp yield and kappa no. to reinforce by cellulose nanofiber. Then, it was refined by PFI mill beater to achieve 385 ml. CSF. The cellulose nanofiber was added in three levels (5, 10 and 15%) to HYKP, then mixed for 5 min. and handsheet made by special wire. The result indicated that 15% adding of cellulose nanofiber to high yield kraft pulp increased tensile index by 39%, burst index by 33%, tear index by 17.7%, bending stiffness index by 38% and ring crush tests (RCT) by 55.47%, respecting to the HYKP. In overall, it is recommended nanofiber adding to HYKP for UTKL making according to the yield and also physical and strength of reinforced pulp.
Physics and Mechanical Wood
Ali Kazemi tabrizi; Amir Nourbakhsh; Javad Sepidehdam
Abstract
In this study, the effect of fish waste powder, base material polyethylene , and also the quantity of coupling agent (MAPE) on physical and mechanical properties of wood-plastic composite were studied. For this purpose, wood powder at 40% was mixed with 60% of HDPE. Fish waste in three levels (5, 10 ...
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In this study, the effect of fish waste powder, base material polyethylene , and also the quantity of coupling agent (MAPE) on physical and mechanical properties of wood-plastic composite were studied. For this purpose, wood powder at 40% was mixed with 60% of HDPE. Fish waste in three levels (5, 10 and 15%) mixed into wood powder and coupling agent on three levels (0, 2 and 4) of HDPE in a blender at 180 °C and a speed rotating of 50 rpm, and samples were made with using of injection molding for standard tests. The mechanical properties: tensile and bending strength, bending and tensile modulus were investigated according of ASTM standards. This result suggests that increasing the amount of fish powder waste to 10%, increased bending strength while other strengths diminished. The amounts of all strengths were increased by increasing in percentage of coupling agent to 4%.The results shows that fish waste was suitable as a new material for wood plastics composites.
Composite wood products
Amir Nourbakhsh
Abstract
This article presents the application of agricultural residues fibers (i.e., corn stalk, reed stalk, and oilseed stalk) in order to evaluate and compare their suitability as reinforcement for thermoplastics as an alternative to wood fibers. The effects of fiber loading and CaCO3 content on the mechanical ...
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This article presents the application of agricultural residues fibers (i.e., corn stalk, reed stalk, and oilseed stalk) in order to evaluate and compare their suitability as reinforcement for thermoplastics as an alternative to wood fibers. The effects of fiber loading and CaCO3 content on the mechanical properties were also studied.Overall trend shows that with addition of agricultural residues fibers, tensile and flexural properties of the composites are significantly enhanced. Oilseed fibers showed superior mechanical properties due to their high aspect ratio and chemical characteristics. The order of increment in the mechanical properties of the composites is oilseed stalk > corn stalk > reed stalk at all fiber loadings. The tensile and Impact properties of the composite significantly decreased with increasing CaCO3 content but flexural modulus increased, due to the reduction of interface bond between the fiber and matrix. It can be concluded from this study that the used agro-waste materials are attractive reinforcements from the standpoint of their mechanical properties.
Composite wood products
Sajad Akbari; Morteza Nazeryan; Saeid reza Farokhpayam; Babak Nosrati sheshkal
Abstract
In this study the possibility of using canola stalks mixed with poplar wood in the manufacture of particleboard was investigated. Weight ratio of canola particle to poplar particles at five levels (98, 93/75, 87/50, 81/25, 77%), the weight ratio of the urea-formaldehyde/melamine formaldehyde resin as ...
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In this study the possibility of using canola stalks mixed with poplar wood in the manufacture of particleboard was investigated. Weight ratio of canola particle to poplar particles at five levels (98, 93/75, 87/50, 81/25, 77%), the weight ratio of the urea-formaldehyde/melamine formaldehyde resin as a adhesive at five levels (23, 18/75, 12/50, 6/25, 2%) and moisture content of matt at five levels (10, 12, 15, 18, 20%) were selected as production variables. Mechanical properties of boards consist of MOR, MOE and IB was tested. According to the results, with increasing the canola stalks/poplar particle ratio MOR and MOE of the boards decreased, but all of the values obtained from treatments were higher than standard. Interaction effect analysis of variables showed that the increasing the ratio of melamine formaldehyde/urea formaldehyde resin decreased the bending strength, while the increasing the moisture of mat increased MOR and MOE. IB values of all treatments are lower than the standard. According to the results of response surface methodology (RSM) and interaction effect between studied variables on the mechanical properties of the panels, the best situation for producing the panels was selected as: weight ratio of 84/32 for canola/poplar particle, ratio of 6/25 for UF/MF resin and moisture content of 12% for mattress.
Management and Economics wood
Azadeh Nikkhah Shahmirzadi; Maryam Ghorbani; Seyed Mojtaba Amininsab
Abstract
This research was conducted to investigate the effect of modification with maleic anhydride and methyl methacrylate on mechanical properties and decay resistance of poplar wood. Samples of mechanical and biological resistance tests were prepared according to ASTM D143-94 and EN113 standards. Treatment ...
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This research was conducted to investigate the effect of modification with maleic anhydride and methyl methacrylate on mechanical properties and decay resistance of poplar wood. Samples of mechanical and biological resistance tests were prepared according to ASTM D143-94 and EN113 standards. Treatment levels were divided into 4 groups; control, methyl methacrylate, maleic anhydride and combined of maleic anhydride/ methyl methacrylate. Samples were impregnated with maleic anhydride and monomer using vacuum- pressure method with experimental cylinder. Maleic anhydride treated samples were heated in oven for 4 and 24 hours at 150 and 103ºC. For polymerization, methyl methacrylate monomer treated samples were heated in oven at 90ºC for 24 hours, consequently at 103ºC for the same time. Methyl methacrylate polymer coating formed on the cell wall, causing 22.57% improvement in the lateral stability under pressure parallel to grain. Highest value in modules of rupture, elasticity and hardness were measured in combined level with 24.13, 47.13 and 45.53% improvement compared with the control, respectively. Maleic anhydride in the presence of methyl methacrylate, with decreasing polarity of the wood and create a good distribution of the particle and the polymer, resulting in the cross linking formation and transmission of uniform tension that would lead to improved mechanical properties. Also, decay resistance was improved in all levels of modification, so that weight loss declined from 80.4% in control to 4.29% in combined level. Modified with maleic anhydride because of the wood composition change, reduction in moisture absorption ability of cell wall and bulking effect, and the presence of methyl methacrylate in the cell cavities as a physical barrier to the movement of fungi mycelium and moisture, were leading to improved decay resistance.
Composite wood products
Amir Nourbakhsh; Abolfazl Kargarfard
Abstract
The main objective of this research was to study the potential of bagasse fibers as reinforcement for thermoplastics as an alternative to wood fibers. The effects of three grades (Eastman G-3003, G-3015 and G-3216) of coupling agents on the mechanical properties were also studied. In the sample preparation, ...
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The main objective of this research was to study the potential of bagasse fibers as reinforcement for thermoplastics as an alternative to wood fibers. The effects of three grades (Eastman G-3003, G-3015 and G-3216) of coupling agents on the mechanical properties were also studied. In the sample preparation, one level of fiber loading (40 wt.%) and three levels of coupling agent content (0, 2 and 4 wt.%) were used. For overall trend, with addition of three grades of the coupling agents, tensile, flexural and impact properties of the composites significantly improved, as compared with untreated samples. In addition, morphological study (SEM) revealed that the positive effect of coupling agent on interfacial bonding. The composites treated with G-3216 gave better results in comparison with G-3003 and G-3015 in which, There are some voids where the fibers have been pulled-out. The presence of these voids means that the interfacial bonding between the fiber and the matrix polymer is weak. This could be caused by the high melt viscosity of G-3216 Coupling agent.
Composite wood products
Saeed Khojasteh Khosro; Saeed Khojasteh Khosro; Mohammad Hasan Payan; Seyyed Mehdi Seyydi
Abstract
In the present research improvement of dimensional stability and mechanical properties of gypsum particleboard by using white cement was investigated. In manufacturing gypsum particleboard, Micronize gypsum was used in three levels of 2.5:1, 2.75:1 and 3:1 to dried mass of wooden materials. White cement ...
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In the present research improvement of dimensional stability and mechanical properties of gypsum particleboard by using white cement was investigated. In manufacturing gypsum particleboard, Micronize gypsum was used in three levels of 2.5:1, 2.75:1 and 3:1 to dried mass of wooden materials. White cement was added in 2 levels of 5 and 10% based on oven dried mass of gypsum to reinforce gypsum particleboard properties. Water absorption, thickness swelling after 2 and 24 hours immersion in water, bending strength, modulus of elasticity and internal bond strength were measured. Vicat needle method was used to investigate the effect of adding cement on setting time of gypsum. The results showed that adding 5% cement based on oven dried mass of gypsum, increased setting time and also mechanical properties. Adding cement over than 5% (10%), significantly improved dimensional stability but reduced setting time of gypsum and mechanical properties of the boards. On the other hand, results indicated that using Micronize gypsum to 2.75 times to dried mass of wooden materials, increased bending strength and modulus of elasticity. Increasing gypsum in to 3 times, reduced bending strength and modulus of elasticity, but improved internal bond strength and dimensional stability.
Composite wood products
mahdi abasyan; asghar omidvar; mahdi mashkour; zinat farhadi
Abstract
This study seeks to investigate the possibility of producing polypropylene composite- cotton stalk flour with various percentages of cotton stalk flour. Determining the best treatment in terms of physical and mechanical properties and exploring the effect of using cotton stalks in the production of the ...
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This study seeks to investigate the possibility of producing polypropylene composite- cotton stalk flour with various percentages of cotton stalk flour. Determining the best treatment in terms of physical and mechanical properties and exploring the effect of using cotton stalks in the production of the composites were among the major objectives of this study. Six treatments consisting of Polypropylene, 40, 55 and 70 percent level of cotton stalks and two fillers (cotton stalks with and without barks) were developed. Maleic anhydride modified polypropylene (3% wt) was applied to each treatment. The mixing and granulation of the plastic and cotton silk flour was carried out using twin screw extruder model 4815. After preparing and shearing of samples, the mechanical properties of composites including tensile strength, rupture modulus and elasticity modulus were calculated in accordance with D-6109 and ASTM D-7031 standards. In addition, water absorption and thickness swelling tests were performed according to D-570-98 standard. The results showed that an increase in the flour of cotton stalk reduced the tensile strength and rupture modulus on the one hand, and increased the bending elasticity modulus on the other hand. In terms of the performance of the filler, there was a significant difference between values of rupture modulus and elasticity modulus at 95% level whereas this difference was not significant for tensile strength. Moreover, this difference was significant for values of water absorption and thickness swelling. The maximum tensile strength belonged to T4 with 40 percent of cotton stalk bark fibers.
Zinat Farhadi; Ahmad reza Saraeian; Mohammad reza Dehghani firuzabadi
Abstract
This study was done to investigate the effect of bark content on the physical and mechanical properties of kraft pulp from chips Ppopulous deltoids. Three tree of the populous deltoids from the same age were randomly selected cut from Shastkalate research forest Gorgan. A disc was taken from each tree. ...
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This study was done to investigate the effect of bark content on the physical and mechanical properties of kraft pulp from chips Ppopulous deltoids. Three tree of the populous deltoids from the same age were randomly selected cut from Shastkalate research forest Gorgan. A disc was taken from each tree. The discs were completely debarked and wet weight of wood and bark from each disc was determined. Then weight ratio of wood/bark was determined in each disc. Kraft pulp was prepared under following pulping condition: sulfidity 25%, AA: 20%, temp: 170 0c, l/w: 6/1 and bark content as 0 , 6, 12, 18 and 24%, by weight. Pulp with kappa number around 20 was prepared from each treatment, which were separately beaten to reach freeness value around 350 ml,CSF. To determined the effect bark content on yield and kappa number of the pulp and their physical and mechanical properties, F test was used in completely randomized, and for comparison of the means, Dunkan test was used. Yield and kappa number of the pulps were as 50/32 - 52/03% and 20/37 - 21/17, respectively. With increasing, of the bark content, density of paper was decreased and the lowest value of which was 0/477 g/cm2for bark – contained pulp. Also, with increasing of the bark content to 18%, strength properties of the related pulp was improved.
Composite wood products
Elham Ostadi; Jalil Morshedian; Yosef Jahani
Abstract
In this research the influence of using waste Poly Ethylene Terephthalate on the mechanical and rheological properties of wood flour filled PP composites has been studied. PET contents varied from 10-33 wt%. Mechanical properties were characterized by tensile testing, while their fracture resistance ...
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In this research the influence of using waste Poly Ethylene Terephthalate on the mechanical and rheological properties of wood flour filled PP composites has been studied. PET contents varied from 10-33 wt%. Mechanical properties were characterized by tensile testing, while their fracture resistance was determined by impact measurements. The melt rheological behavior of the composites was also studied by a rheometer in the oscillatory mode and dynamic rheological properties such as complex viscosity, storage modulus, loss modulus and damping factor were evaluated at190°C. The results showed that stiffness increases by adding waste Poly Ethylene Terephthalate. PET when added in low concentrations, caused tensile strength to be lower than that of PP composites filled with pure wood flour. Increasing the concentration of waste PET, led to composites with higher amount of tensile strength. The samples containing waste PET had higher complex viscosity and storage modulus than composite without PET. Likewise, it was observed that the damping factor in the PP/Wood composite decreased by incorporating waste PET to the compositions. Key words: waste polyethylene terephthalate, polypropylene, wood flour, mechanical properties, rheological behavior
Composite wood products
Aliakbar Aenayati; Halimeh Pangh; Mahammad Layeghi; Kazem Doosthosseini
Abstract
This study was conducted to investigate the effect of Cu nano particles addition on the density profile and mechanical properties of medium density fiberboard. One layer fiberboard (MDF) with the density of 0.58g/cm3and thickness of 17 mm were produced using Cu nano particles in three levels (5, 10 and ...
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This study was conducted to investigate the effect of Cu nano particles addition on the density profile and mechanical properties of medium density fiberboard. One layer fiberboard (MDF) with the density of 0.58g/cm3and thickness of 17 mm were produced using Cu nano particles in three levels (5, 10 and 15wt%based on solid content of resin) and urea formaldehyde resin content in two levels (8 and 10wt%based on oven dry weight of fibers) as variable factors. The control panels were produced using 10% resin (based on oven dry weight of fibers) without Cu nano particles using the identical manufacturing parameters as other panels. Mechanical strength including internal bonding (lB), bending strength, modulus of elasticity and density profile using slicing method were determined. The results indicated that increasing the content of Cu nano-particles had no significant effect on the internal bonding as well as bending strength and modulus of elasticity of panels. Increasing the resin content from 8 to 10 percent improved modulus of elasticity (43.7%), bending strength (18.9%) and internal bonding (23%) of panels. In addition, the increasing Cu nano particles up to 5% caused relatively higher IB for panels produced using 8%resin compared to the control panels(containing10% resin) as well as the density profile was more uniform with the lowest differences between maximum and minimum density in the density profile.
Management and Economics wood
Lila Asadi khoramabadi; Abolghasem Khazaeian; Mohammad reza Masteri Farahani; Alireza Shakeri
Abstract
Heat treatment is one of the processes used to modify the properties of wood. The investigation of thermal treatment of wood has led to the improvement of heat treatment with vegetable oils. Heat treatment improves the dimensional stability and biological durability, but reduces the mechanical properties ...
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Heat treatment is one of the processes used to modify the properties of wood. The investigation of thermal treatment of wood has led to the improvement of heat treatment with vegetable oils. Heat treatment improves the dimensional stability and biological durability, but reduces the mechanical properties of wood. In this research, to improve the mechanical properties with other properties of wood, soybean oil modified with maleic anhydride was used for thermal treatment. Wood speciments were subjected to heat treatment soybean oil modified with maleic anhydride at two temperature (180 and 200° C ) and three time (2, 4 and 6 hours). Untreated beech was used as comparison for each treatment conditions. In this study, the effects of heat treatment on physical properties )water absorption and volumetric changes) and mechanical properties such as Bending strength) ISO 3133-1975(, Compression strength Parallel to grain) ISO 3787-1976 (and Impact bending) DIN 52189( were examined. The test results of heat-treated with modified soybean oil and control samples showed that physical and mechanical properties increases with heat treatment.
Composite wood products
Ghonche Rassam; Hamid Reza Taghiyari; Bratali Keshtegar
Abstract
Wood-composites are susceptible to fire due to their nature. Some research projects were therefore carried out to investigate potentiality of bentonite nanoparticles in improving fire-retarding properties in medium-density fiberboards (MDF); the present complimentary study aimed at determining the effects ...
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Wood-composites are susceptible to fire due to their nature. Some research projects were therefore carried out to investigate potentiality of bentonite nanoparticles in improving fire-retarding properties in medium-density fiberboards (MDF); the present complimentary study aimed at determining the effects of nanobentonite on physical and mechanical properties of MDF. Ten percent of urea-formaldehyde resin was used as adhesive in the matrix. Nano bentonite was added at 5 levels (%0 ,% 5 ,% 10 , %15 and %20) g/kg based on the dry weight of fibers. Bentonite nanoparticles were sprayed on the fibers after being mixed with the resin solution. Mats were hot-pressed for 4, 5, and 6 minutes at temperature of 170°C. Density was kept constant (75 g.cm-3) for all treatment. Results revealed that nano Bentonite did not improve the physical properties of water absorption, thickness swelling and mechanical properties of internal bonding (IB), modulus of elasticity (MOE), modulus of rupture (MOR). As to the other treatments, nano Bentonite consumption level of % 5 showed the lowest negative effect on the physical properties (water absorption, thickness swelling ) and treatment of 5% and %10 also less negative effect on the Mechanical properties (Modulus of rupture, Internal Bonding ). Treatment 20% is not recommended because it weakens the properties; moreover, the surface of fiberboards is not suitable. It was concluded that due to the fire-retarding improving effects, %5 of nano Bentonite is recommended as the optimum level for the industry.
