Chemical conversion
Saeed Hasani; Mohammad Talaei poor; behzad baziyar; Amir Homan Hemmasi; Saeed Mahdavi
Abstract
AbstractIn this study, black poplar (Populus nigra) cut from Zanjan province was used in two age groups of 18 and 38- year-old. Timbers with thicknesses of 4, 5 and 6 cm were prepared from each age group. The prepared timbers were modified during the heat treatment process (Thermowood) at a constant ...
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AbstractIn this study, black poplar (Populus nigra) cut from Zanjan province was used in two age groups of 18 and 38- year-old. Timbers with thicknesses of 4, 5 and 6 cm were prepared from each age group. The prepared timbers were modified during the heat treatment process (Thermowood) at a constant temperature of 212 °C. Experimental samples were obtained from the surface and middle depth of heat-treated timbers. Heat-treated and control wood samples were subjected to accelerated weathering for 150 hours. Color lightness (L*), color difference (ΔΕ*) and water droplet contact angle were measured for heat-treated and control samples before and after weathering. In order to investigation of the wettability content, the method of measuring the contact angle of the water drop - static according to the ASTM D 5946 standard was used. In general, before weathering, the brightness of the heat-treated samples decreased compared to the control sample, but after weathering, the color lightness of the control samples decreased and the color lightness of the heat-treated samples increased. Also, the content of color difference of samples after weathering compared to before weathering showed a significant decrease statistically. Heat treatment increased the contact angle of water droplets of the samples 60.31% and the contact angle of water droplets of the heat-treated and control samples increased significantly after weathering compared to before weathering.
Afsaneh Topa; Atamalek Ghorbanzadeh; Davood Efhamisisi
Abstract
The plasma has different effects on the surface wettability of wood, depending on the treatment conditions and the type of gas used. The hdrocarbon gases usually destroy hydrophilic groups on the surface of wood and cause hydrophobicity by creating microscopic rough structures. In this study, glide plasma ...
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The plasma has different effects on the surface wettability of wood, depending on the treatment conditions and the type of gas used. The hdrocarbon gases usually destroy hydrophilic groups on the surface of wood and cause hydrophobicity by creating microscopic rough structures. In this study, glide plasma treatment with methane was used to hydrophilize the surface of the wood and create weathering resistanc. The poplar wood (Populus deltoides) were exposed to glide plasma under various laboratory conditions such as time of exposure, voltage, frequency, distance between electrodes as well as flow of inlet gas and outlet gas with methane inside a reactor. Then the surface properties of wood were studied using scanning electron microscope (SEM), measurement of water drop contact angle, ATR‐FTIR spectroscopy, roughness survey, and colorimetry. The specimens were then subjected to the accelerated weathering using the Gardner weathering wheel and their properties were checked again. The SEM images showed that the plasma creates a warty layer on the surface of the wood which could be due to the deposition of new materials or the physical effects of plasma (surface etching). The plasma treatment significantly increased the contact angle of the water droplet on the surface of the treated samples. The treated samples had a higher surface roughness than the control samples. The surface of treated samples was generally darker than the control. After exposure to the accelerated weathering, the effect of treatments on surface hydrophobicity was largely lost. The treated samples had less roughness changes than the control after exposure to the weathering, and also their dark color changed to silver-gray. The use of glide plasma with methane gas showed the great potential for creating hydrophobic surfaces on the wood, but it did not last long and lost its effectiveness due to weathering.
Reza Hajihassani; Saman Ghahri; Kamyar Salehi; Fardad Golbabaei; seyedeh masoomeh
Abstract
Abstract In the current research, surface properties and failure modes of modified poplar wood (Populus deltoides) by hygrothermal treatment were evaluated. For this aim, the effect of variable factors included hygrothermal temperature (three levels: 130, 150 and 170°C) and holding time (two levels: ...
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Abstract In the current research, surface properties and failure modes of modified poplar wood (Populus deltoides) by hygrothermal treatment were evaluated. For this aim, the effect of variable factors included hygrothermal temperature (three levels: 130, 150 and 170°C) and holding time (two levels: 20 and 40 minutes) on poplar wood specimens properties (contact angle and surface roughness) prior to and after planning were investigated. The surface characteristics and failure modes were evaluated for both treated and untreated wood specimens. The results revealed that surface roughness of poplar wood was enhanced due to the hygrothermal treatment in both states of before and after planning. It was also found that the hygrothermal treatment decreased contact angle of distilled water. The bending strength of specimens was reduced by hygrothermal treatment. According to the results, failure modes of hygrothermally treated specimens were simple and compression types in bending strength test. Keywords: Surface roughness, contact angle, bending strength, failure mode
rouzbeh asadi khansari; Mohammadreza Dehghani Firouzabadi; Hossein Resalati
Abstract
The purpose of this research is to evaluate the effect of various paper coatings on initial contact angle and its evolution over time. We investigated nine coatings on two types of 75 g and 125 g printing papers. Seven coating compositions containing 80% clay, 20% ground calcium carbonate, dispersing ...
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The purpose of this research is to evaluate the effect of various paper coatings on initial contact angle and its evolution over time. We investigated nine coatings on two types of 75 g and 125 g printing papers. Seven coating compositions containing 80% clay, 20% ground calcium carbonate, dispersing agent and various levels of polyvinyl acetate and lactic acid as binders were used. In the last two coatings, we used 100% precipitated calcium carbonate pigments, cationic starch, methacrylate, dispersant and two levels of cellulose nanofibers. In these suspensions, the amount of cellulose nanofibers in composition 8 is twice composition 9. After coating using rod method, the papers were dried then coated and control samples were calendered. We then performed contact angle measurements using water droplet and Kit No were performed. We noticed largest contact angle and smallest angle change over time for sample 6 containing 75% binder. Last two coatings contained cellulose nanofibers, which caused presence of hydroxyl group on the surface and lowered the contact angle. Composition eight was the most hydrophilic sample. Best barrier property Kit No and largest droplet volume after 20 seconds was accompanied with the increase of the binder percentage in the formulation. For the control sample and three treatments with highest binders, the contact angle over time remains relatively constant which is a sign of hydrophobicity. The correlation between contact angle and volume of the water droplet was determined to be 0.951 and 0.936 in the 75g and 125g papers relatively. We did not notice a significant difference in contact angle and Kit No between 75g and 125g samples.
Mechanical conversion of wood and wooden fittings
Hadi Gholamiyan
Abstract
In this study, the effect of corona treatment on improving the durability of nitrocellulose and polyurethane coatings used in the wood furniture industry before and after weathering investigated. The boards made from poplar and beech were coated by an automatic film applicator after corona treatment ...
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In this study, the effect of corona treatment on improving the durability of nitrocellulose and polyurethane coatings used in the wood furniture industry before and after weathering investigated. The boards made from poplar and beech were coated by an automatic film applicator after corona treatment and accelerated for 30 days in a weathering machine. Then, the contact angle, abrasion resistance, and pull-off adhesion testing to the wood surface coatings were analyzed. The results showed that corona treatment reduced contact angle in wooden species and the highest contact angle reduction found in beech wood. Also, the results of the adhesion test showed that the highest adhesion was related to the polyurethane coating and after weathering, the adhesion of the coatings decreased, but the use of corona treatment, in addition to increasing the adhesion strength before weathering, could significantly improve adhesion after weathering. The results of the abrasion test showed that the wear resistance increased in wooden species due to the coating, and the highest amount observed in the beech-coated with polyurethane. After weathering, wear resistance was reduced in all samples, but using corona treatment increased resistance to abrasion. In general, it can say that the use of corona treatment can significantly (95%) improve the resistance to mechanical properties and durability of coatings before and after weathering and thus increase the durability of the furniture and wooden structures.
Pulp and paper
somayeh heydari; Ahmad Reza Saraeyan; Mohammad Reza Dehghani Firouzabadi; Alireza Shakeri; babak shokri
Abstract
DOR:98.1000/1735-0913.1398.34.100.66.1.9.1604 In this study, EVOH was coated on paper made of CMP pulp by extrusion method in order to improve the paper's barrier properties of oxygen transmission. Ethylene vinyl alcohol (EVOH) shows poor moisture resistance despite less gas permeability. Then, dimethoxydimethylsilane ...
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DOR:98.1000/1735-0913.1398.34.100.66.1.9.1604 In this study, EVOH was coated on paper made of CMP pulp by extrusion method in order to improve the paper's barrier properties of oxygen transmission. Ethylene vinyl alcohol (EVOH) shows poor moisture resistance despite less gas permeability. Then, dimethoxydimethylsilane was deposited using Plasma Enhanced Chemical Vapor Deposition on EVOH film as the hydrophobic layer. A random factorial experiment was designed with three factors at three levels including time (6-8-10 min), pressure (30-0400-500 m Torr), and radio frequency power (50-70-90 W). The contact angle, oxygen transmission rate, tensile strength, and strain energy were measured to obtain the optimum condition. Expert Design method using response surface was used to optimize the condition coating Dimethoxydimethylsilane in order to improve the hydrophobic properties, reduce OTR, increase tensile strength and strain energy. Based on this method the optimum condition was suggested as: time 6 min, pressure 499.99 m Torr and power 50W. Keywords: Extrusion , Contact angle, Oxygen transmission rate, Response Surface methodology.
Pulp and paper
Zohreh Taheri; Hamidreza Rodi; Hossein Jalali-Torshizi; Reza Shidpour
Abstract
DOR:98.1000/1735-0913.1398.34.112.66.1.1578.1610 Nowadays, the barrier property against water take up of different packaging papers which mostly prepared from recycled fibers is of highly significance for paper manufacturers. In current study, the effect of AKD sizing agent has been examined on the properties ...
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DOR:98.1000/1735-0913.1398.34.112.66.1.1578.1610 Nowadays, the barrier property against water take up of different packaging papers which mostly prepared from recycled fibers is of highly significance for paper manufacturers. In current study, the effect of AKD sizing agent has been examined on the properties of papers made from recycled fibers of Atrak pulp and paper industries. Sizing of pulp suspension using AKD was conducted at levels of 0, 0.5, 1 and 1.5 % based on oven dry (OD) pulp in neutral pH (7), according to the TAPPI standard methods. Then, by preparation of handsheets with basis weight of about 60±3 g/m2, their Cobb test (60 second) and different characteristics were evaluated. According to the statistical analysis of the results, up to 1 % AKD consumption amount based on OD pulp exhibited for optimum level in internal sizing of these recycled fibers. In such AKD level, water take up of size-free papers revealed 174±7.4 g/m2, decreased to the value of about 24±1.7 g/m2 in AKD-treated papers. Further, contact angle of water droplet with the paper surface increased from 35.2º to 109.1º. Applying 1 % of AKD, paper tensile index increased to 33.2±1.01 N.m/g by 2.4 unit compared to the base paper. Apparently, such phenomena can be attributed to the AKD potential in creating hydrogen bonds which concurrent to the development of paper water repellency, resulted in improving bonding-ability of paper network. Additionally, AKD treatment led to in meaningful increase of paper opacity. This can also be attributed to the increase in filler retention in fibers network, which influences the development of light scattering from the paper surface.
Pulp and paper
Bagher Ashrafi Rad; Mohammad Azadfallah; Fatemeh Kolaei Moakhar; Soheila Izadyar; Mehdi Rahmaninia
Abstract
Utilization of paper as packaging material and developing applied technological program on paper-based substrate are drastically dependent to control of cellulosic fiber hydrophilicity and to enhancement of its hydrophobic properties. Then this work carried out with the aim of developing hydrophobic ...
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Utilization of paper as packaging material and developing applied technological program on paper-based substrate are drastically dependent to control of cellulosic fiber hydrophilicity and to enhancement of its hydrophobic properties. Then this work carried out with the aim of developing hydrophobic surface on cellulosic fiber with layer by layer (LBL) method while keeping and enhancing the properties of paper network. The deposition was implemented by titanium dioxide nanoparticles and poly acrylic acid as cationic and anionic layer respectively on the fibers of unbleached hardwood Kraft pulp and using Zycosil and fluoroalkyl silane on the last layer. The hand-sheets were then made by this modified fiber. The contact angle and roughness were measured to evaluate the effect of layers on hydrophobicity. The results indicated that roughness increased with the number of layers. The instant contact angle was also increased with the number of layers and reached approximately to 110 degree at 7th layer. The dynamic contact angles dropped more lately with increasing the number of layers. The fluorosilane deposition as 8th layer in comparison with Zycosil showed more effect on surface energy reduction. The instant contact angle of Zycosil treated paper was measured 125 degree which dropped significantly to 48 degree after 30 seconds. However, fluorosilane modified paper exhibited contact angle of 140 degree at the same time. In addition, the presence of titanium dioxide nanoparticles on the surface of fiber was demonstrated by scanning electron microscopy (SEM) of paper surface.
Pulp and paper
Fatemeh Naijian; Hossein Resalati; Hamid reza Rodi; Hossein Jalali-Torshizi; Kamal Pirmoradian
Abstract
Nowadays, recycled fibers are the main fiber source for manufacturing packaging papers. Sizing of such papers, based on the type of application, is of great importance. In this research, the effect of alum-cationic rosin consumption amount in pH of about 6.5 on the properties of papers made from white ...
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Nowadays, recycled fibers are the main fiber source for manufacturing packaging papers. Sizing of such papers, based on the type of application, is of great importance. In this research, the effect of alum-cationic rosin consumption amount in pH of about 6.5 on the properties of papers made from white sheets trimmings was examined. In order to optimize consumption extent, pulp suspension sizing with alum in six level of 0, 4, 5, 7, 8, and 10 %, and rosin with the ratio of 50 % of alum based on oven dry (OD) pulp was done according to the TAPPI standard methods. Then by preparation of handsheets with basis weight of about 65±5 g/m2, their Cobb test (45 second), structural and strength characteristics were investigated. Statistical analysis of the results have shown that alum and rosin consumption amount of about 7 and 3.5 % based on OD pulp is the best suitable level for internal sizing of white sheets trimmings fibers. In these alum-rosin level, Cobb value of papers decreased from 120±11.6 g/m2 the lowest value of about 64±9.7 g/m2. Contact angle of water droplet with the paper surface increased from 24.81º to 96.53º. Paper tensile index decreased up to 125±9.7 N.m/g by such sizing level and again increased with increasing alum-rosin level. Seemingly, such phenomena can be attributed to the alum role in charge neutralizing, cellulosic fines retention and improving bonding-ability of paper network. Meaningful decrease of paper surface roughness from 10.34±0.54 µm in control sample to 8.23±1.37 µm in sized papers in optimized level confirmed this assumption.
Composite wood products
Fatemh Rezaei; Ali akbar Enayati
Abstract
In this research, the effect of vine pruning fibers in combination with wood fibers on contact angel (wettability) and surface bond strength of medium density fiberboard was studied. One layer laboratory panels with a thickness of 15 mm and density of 650 Kg/Cm3 were produced. Variable factors were vine ...
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In this research, the effect of vine pruning fibers in combination with wood fibers on contact angel (wettability) and surface bond strength of medium density fiberboard was studied. One layer laboratory panels with a thickness of 15 mm and density of 650 Kg/Cm3 were produced. Variable factors were vine pruning fibers content in three levels of 0/100, 30/70 and 60/40 by weight and press time in three levels of 4, 5 and 6 minutes. The wet ability and surface bond strength of panels were measured. Results showed that the contact angle of the boards was reduced when the vine pruning fibers content increased up to 60%. Press time had significant influence on wet ability of test panels. So that the contact angle was increased with increasing the press time up to 5 minutes. Whereas the contact angle was reduced when the press time of panels increased to 6 minutes. In addition, the results indicated that the sanding of panels caused a decrease of contact angle in the boards. Moreover the surface bond strength of panels were reduced with adding vine pruning fibers up to 30% whereas the panels produced using 60% vine pruning fibers showed stronger.
Management and Economics wood
Mohammad Saleh Hosseini Fard; Saeed Khojasteh Khosro; Behbod Mohebby
Abstract
In this research the effect of oil-heat treatment of Fir species (Abies spp) on contact angle and adhesion strength of organic solvent based and water based coating (acid catalyzed and acrylic water based coating) were investigated. Soy oil was used for the heat treatment modification. Modification process ...
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In this research the effect of oil-heat treatment of Fir species (Abies spp) on contact angle and adhesion strength of organic solvent based and water based coating (acid catalyzed and acrylic water based coating) were investigated. Soy oil was used for the heat treatment modification. Modification process of samples were done at two time, 12 and 15 hours with temperature of 180°C. Control and modified samples were covered with acid catalyzed and acrylic water based coating. Contact angle of water was measured before and after treatment. Adhesion strength of coating was determined according to ASTM 4541 standard. Obtained results of contact angle and adhesion strength were compared with the control samples. The results showed that modification process of oil-heat treatment increased contact angle. This increase continued by increasing treatment time. Increasing contact angle reduced wettability of samples’ surface. On the other hand oil-heat treatment of wood, decreased adhesion strength of coating. The lowest value of adhesion strength was observed in the modification process of 15 hours. Results of comparing coating revealed that acid catalyzed coating had higher adhesion strength than acrylic water based coating but generally no significant differences was observed between these coating.
Neda Moradpour; Mohammad reza Mastari frahani; Alireza Shakeri
Abstract
To investigate the effect of acetylation and antioxidant separately and together on discoloration and contact angle wood plastic composite due to weathering , composite s were made using popular wood flour and high density polyethylene . the sample were exposed to natural weathering for 6 ...
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To investigate the effect of acetylation and antioxidant separately and together on discoloration and contact angle wood plastic composite due to weathering , composite s were made using popular wood flour and high density polyethylene . the sample were exposed to natural weathering for 6 months.
The results have shown that acetylation can relatively reduce the discoloration of weathered sample treatment than control sample.the antioxidant does not have any influence on color change but it seems that antioxidant could prevent partly destruction of plastic .
It should be mention acetylating increased the surface contact angle befor weathering. But it could not protect the sample surface after the exposure period. So that was zero after weathering.
