Mohammad Ghofrani
Abstract
AbstractIn this study, alumina nanoparticles was added to clear varnishes (Sealer, clear, semi-polyester and polyurethane), and changes in adhesion strength on wood specimens of Walnut (Juglans Regia) and spruce (Picea Spp) were studied. The experimental samples were prepared from defect-free woods with ...
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AbstractIn this study, alumina nanoparticles was added to clear varnishes (Sealer, clear, semi-polyester and polyurethane), and changes in adhesion strength on wood specimens of Walnut (Juglans Regia) and spruce (Picea Spp) were studied. The experimental samples were prepared from defect-free woods with size of 300×100×10 mm and dried to 8 % moisture content in air drying and Killen drying, respectively. The samples surfaces finished and the clear varnishes applied on samples surfaces using pneumatic spry gun and the adhesion strength test was done on samples. The result of this study showed that the highest adhesion strength was observed in polyurethane varnishes with 6% alumina nanoparticles in walnut wood, and the lowest adhesion strength observed in cellulosic varnishes (sealer and clear) with 0% nanoparticles in spruce wood. It can be concluded that with the control of nano alumina percentage in varnishes in a defined level, the adhesion strength of the clear varnishes increased. Also, with improvement of varnishes’ adhesion strength on wood surface, the varnishes durability increased, consequently.
Management and Economics wood
anooshe fazeli; mohammad ghofrani; fatemeh Hassani khorshidi
Abstract
The present study was conducted to inverstigate the effect of moisture content on adhesion strength of sealer half-polyester and sealer polyurethane on beech (Fagus orientalis) and hornbeam (Carpinus betulus) wood types of northern regions of Iran. PH values of beech and hornbeam was 5.51 and 5.19, respectively. ...
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The present study was conducted to inverstigate the effect of moisture content on adhesion strength of sealer half-polyester and sealer polyurethane on beech (Fagus orientalis) and hornbeam (Carpinus betulus) wood types of northern regions of Iran. PH values of beech and hornbeam was 5.51 and 5.19, respectively. Dried specimens were put in a climatization room to reach moisture contents of 7%, 11% and 15%. After the preparation stage, two layers of sealer were placed on the specimens using a spray. Next, polyurethane and half-polyester were applied to the specimens. The pull-off test was performed on the specimens according to the ASTM D 4541 Standard. The results showed that the most adhesion strength was that of the sealer polyurethane used on the beech wood type with the moisture content of 7 percent and the least adhesion strength belonged to the sealer half-polyester used on the hornbeam wood type with the moisture content of 15 percent. It was also observed that increasing moisture content caused a decrease in adhesion strength of both wood types.
Management and Economics wood
Saeed Khojasteh Khosro; Masoud Taghipour Javy
Abstract
The main objective of the current study was the investigation of the effect of adding the wollastonite nanoparticles (casio3) to the water based acrylic coating onto the fire resistance capability and adhesion strength of coating. The nano wollastonites with the concentrations of 0.5, 1.50, and 2.5 wt% ...
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The main objective of the current study was the investigation of the effect of adding the wollastonite nanoparticles (casio3) to the water based acrylic coating onto the fire resistance capability and adhesion strength of coating. The nano wollastonites with the concentrations of 0.5, 1.50, and 2.5 wt% were dispersed into the coating. Ultrasonic device was used to stabilize the nanoparticles into the substrates. The coating process was carried out with and without application of the nanoparticles on the surfaces of spruce and sycamore samples and their properties comprising the fire resistance and the adhesion strength were investigated. The obtained results showed that adding of nano wollastonite to the acrylic coating with the waight percent of 2.5% (w/w) had the significance effect onto the resistance of the samples to fire. In particluar, these effects was observed in cas of the retard time of ignition of the spruce and sycamore samples with the improvement values of 258 and 184 % compared with the control samples, respectively. Furthermore, the investigation of adhesion properties of coatings to the sample surface indicated that the applied nano wollastonites improved these properties of coatings. In case of the adhesion properties, however, the highest value of this properties was observed in the highest content of wollastonite nanoparticles. It should be noted that the performance of nanocomposite coating containing of the 1.5 wt% of nano onto investigated properties was also acceptable.
Management and Economics wood
Fatemeh Hasani Khorshidi; Mehdi Emadi
Abstract
In this study, effect of accelerated aging on adhesion strength of half-polyester and polyurethane transparent coatings were evaluated in maple and pine species. For this purpose, dried specimens with 12×110×550 millimeters were used. Sealer as substrate, and half-polyester and binary polyurethane ...
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In this study, effect of accelerated aging on adhesion strength of half-polyester and polyurethane transparent coatings were evaluated in maple and pine species. For this purpose, dried specimens with 12×110×550 millimeters were used. Sealer as substrate, and half-polyester and binary polyurethane as coatings were applied on wood. Coatings were implemented thereby film applicator and gun methods, and accelerated aging test of wood specimens was carried out according to ASTM D1037. Results indicated that maximum value of adhesion strength is belong to binary polyurethane in maple applied by film applicator and minimum for half-polyester in pine applied by gun method, in opposite. Due to thin film, velocity variations in gun method by painter person, and consequent rapid evaporation of thinner, adhesion decreased in comparison with film applicator method. Also it's found that accelerated aging diminished adhesion strength of coatings in both maple and pine species. It can be concluded during the accelerated aging test, the steam causes moisture absorption and swelling of the fibers near the surface and thus reduce the resistance of the coating adhesion.Long-term effect of humidity and aging makes Ecowool quickly lose their stickiness.And the effect of floating in the water samples, lignin degradation products in the process of steaming and freezing and heating washed by water And cause the loosening of the cellulosic fibers in the wood, resulting in wood adhesive strength is significantly reduced due to the accelerated aging test.
Negin Nikbin; Saeid Mahdavi; Hossein Kermanian; Omid Ramezani; Amir Mohssen Nazeri
Abstract
Native starch has relatively suitable characteristics including biodegradable properties, being widely used as an adhesive in the corrugated carton manufacturing companies. Corn starch is currently used in the companies for producing adhesives. In this study, fines of NSSC pulp as natural additive and ...
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Native starch has relatively suitable characteristics including biodegradable properties, being widely used as an adhesive in the corrugated carton manufacturing companies. Corn starch is currently used in the companies for producing adhesives. In this study, fines of NSSC pulp as natural additive and ammonium persulfate as chemical oxidative additive were used to improve the adhesion properties of corn starch. Fine was added at three levels of 5%, 10%, and 15% (based on oven-dry weight of starch) and ammonium persulfate similarly was mixed at 5 levels of 0.1, 0.2, 0.3, 0.4 and 0.5 grams. Addition of fine was lead to increasing adhesion strength (PAT) of the corrugating board to the amount of 25%, 35% and 43% respectively. This improvement could be due to increasing the number and strength of hydrogen bonding of fiber layers (corrugating and liner paper) and value of solid content. Addition of ammonium persulfate revealed that the method applied similar to mixing fine had no desirable results and the other methods should be used.