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% ...
Read More
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.
Mechanical conversion of wood and wooden fittings
Mohammad Ghofrani; Zahra Mohammad Moradi; Saeed Khojasteh Khosro
Abstract
In present study the effect of different methods of applying transparent coatings on adhesion strength of coating in Walnut (Juglans regia), Maple (Acer velutinum) and Pine (Pinus eldarica) species was investigated. For this purpose, samples prepared with dimension of 200×100×20 mm and 8% ...
Read More
In present study the effect of different methods of applying transparent coatings on adhesion strength of coating in Walnut (Juglans regia), Maple (Acer velutinum) and Pine (Pinus eldarica) species was investigated. For this purpose, samples prepared with dimension of 200×100×20 mm and 8% moisture content. Samples’ surfaces were sanded with 100, 120 and 180 grate sizes sandpaper significantly. Then after preparation wooden samples with sealer, their surfaces covered with clear and acid catalyzed transparent finish in separate process by using spray gun and applicator. Adhesion strength of coating was measured with Pull-Off method based on ASTM D4541 standard. Fluorescence microscopy test used for investigation coating penetration in spray gun and applicator method. Results showed that the method of applying coating on wooden surfaces has significantly affected adhesion strength, and highest adhesion strength between all samples, observed in samples coated with applicator method. Investigation of coating penetration indicated that applicator method had good penetration in wood substrate in comparison spray gun method. Highest differences in adhesion strength of coating between spray gun and applicator method were observed in Walnut and Maple’s samples. In general, highest adhesion strength of coating was found in Walnut samples covered with acid catalyzed transparent finish by using applicator method.
Management and Economics wood
Mohammad Ghofrani
Abstract
In this study, the effect of heat treatment of Alder (Alnus glutinosa), Poplar (Populus nigra) and Spruce (Picea abies) on adhesion strength of clear and acid catalyzed transparent coating was investigated. For this aim, wooden samples were prepared with dimension of 200×100×18 mm (longitudinal, ...
Read More
In this study, the effect of heat treatment of Alder (Alnus glutinosa), Poplar (Populus nigra) and Spruce (Picea abies) on adhesion strength of clear and acid catalyzed transparent coating was investigated. For this aim, wooden samples were prepared with dimension of 200×100×18 mm (longitudinal, tangential, radial) from sapwood on tangential surface. Samples were kept under heat treatment in oven with 150 and 180˚C temperatures for about 3 hours. After treatment, samples’ surfaces were sanded with 120 and 180 grit size sand paper, respectively. Contact angle of water was measured before and after treatment. Samples’ surfaces were covered with a transparent coat in two separate processes which were clear and acid catalyzed. Adhesion strength of coating measured with Pull Off method according to ASTM D-4541 standards. Results showed that the heat treatment increased contact angle. This increase continues as the heat treatment temperature goes higher and it leads to decrease in wettability of samples’ surfaces. Results also indicated that heat treated of wood had significant effect on adhesion strength of coating. Adhesion strength in control samples was more than heat treated samples. lowest coating strength was observed in samples which were heat treated in 180 ˚C.
Management and Economics wood
Saeed Khojasteh Khosro; Mohammad Ghofrani; Morteza Ganjaei sari
Abstract
In this study the effect of adding zinc oxide nanoparticles (ZnO) on color change and adhesion strength of polyurethane clear coat in Elm wood species (Ulmus glabra) investigated. ZnO nanoparticles with concentration of 0, 0.25, 0.50, 1, 1.50 and 2 wt% were dispersed in coating. TEM (Transmission electron ...
Read More
In this study the effect of adding zinc oxide nanoparticles (ZnO) on color change and adhesion strength of polyurethane clear coat in Elm wood species (Ulmus glabra) investigated. ZnO nanoparticles with concentration of 0, 0.25, 0.50, 1, 1.50 and 2 wt% were dispersed in coating. TEM (Transmission electron microscopy) images were used for investigate the dispersion of nanoparticles in coatings matrix. Results of investigate the dispersion of nanoparticles in polyurethane coating indicated that the best dispersion of nanoparticles obtained in coating with 1 wt% nano. Increasing concentration of nanoparticles to 2 wt%, reduced dispersion of nanoparticles and aggregates of nanoparticles observed in coating. Investigation adhesion strength of coating showed that the highest value of adhesion was in nanocomposite coating with 1 wt% nano but increasing nanoparticles more than this content, had negative effect on coating adhesion. Results also revealed that adding ZnO nanoparticles, changed color of samples coated with nanocomposite coating but it was not significant in low content of nanoparticles.
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 ...
Read More
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.
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 ...
Read More
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.
