Davood Rasouli; Hossein Yousefi; Mahdi Mashkour
Abstract
In this research, the effect of using nano-zinc oxide (nano-ZnO) as a UV absorbent on the weathering resistance of wood- polypropylene composite was investigated. For this purpose, composite samples containing 0, 1, 2 and 3% nano-ZnO were manufactured using an internal mixer and a laboratory press. ...
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In this research, the effect of using nano-zinc oxide (nano-ZnO) as a UV absorbent on the weathering resistance of wood- polypropylene composite was investigated. For this purpose, composite samples containing 0, 1, 2 and 3% nano-ZnO were manufactured using an internal mixer and a laboratory press. The prepared specimens were exposed to artificial weathering for 1480 hrs (in the periods of 0 ,480, 960 and 1480 hrs). The weathering degradation of specimens was monitored by tensile strength, hardness, colorimetry, Fourier transform infrared spectroscopy (FTIR), and, stereomicroscope tests. Results showed that weathering caused color changes, tensile strength and hardness loss, physical and chemical degradation on the surface of the samples. The use of nano-ZnO partially prevented tensile strength and hardness loss of samples as well as their surface degradation. In general, the use of 2% nano ZnO has been a better performance against weathering than other values.
Hossein Yousefi; Elyas Afra; Davood Rasouli; mahdi mashkour
Abstract
In this study, paper and nanopaper were first produced and then treated with dodecyltriethoxysilane to prepare water repellent cellulose paper and nanopaper were made using dodecyltriethoxysilane. As the result of silane treatment, the hydrophilic surface of paper and nanopaper converted to hydrophobic ...
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In this study, paper and nanopaper were first produced and then treated with dodecyltriethoxysilane to prepare water repellent cellulose paper and nanopaper were made using dodecyltriethoxysilane. As the result of silane treatment, the hydrophilic surface of paper and nanopaper converted to hydrophobic surfaceones. The micrographs of FE-SEM confirmed the nano-scale size of cellulose nanofibers. XPS results showed that the surface of specimens contains silane. With the treatment of silane, the water droplet contact angle increased to 104 and 153 degree in nanopaper and 153 paper, respectivelydegree in paper. Because of this, the surface of treated paper can be regarded as super hydrophobic surface. TGA confirmed that the ash content of treated specimens were higher than those of untreated ones and also it was revealed that the silane treatment made a multi-layers coating on the surface of specimens. The treated specimens showed less water absorption and higher mechanical properties than untreated ones. The silane coupling treatment made water hydrophobic surfaces onof cellulose paper and nanopaper made them water-proof which can led to the development of their applications for outdoorshumid conditions.
Chemical conversion
mahdiye mazandarani; ali ghasemian; ahmadreza Saraeyan; mahdi mashkour; SeyedRahman Jafari Petroudy
Abstract
In the present study, preparation of cotton stalk (Sahel variety) as one of the common agricultural residues was studied through three stages as Soda-AQ chemical pulping, delignification and alkaline treatment, aiming for the production of cellulose nanocrystal. In order to identify the optimum condition ...
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In the present study, preparation of cotton stalk (Sahel variety) as one of the common agricultural residues was studied through three stages as Soda-AQ chemical pulping, delignification and alkaline treatment, aiming for the production of cellulose nanocrystal. In order to identify the optimum condition for the preparation of cellulose nanocrystal, acidic hydrolysis of the produced alpha-cellulose was done using 64% sulfuric acid, 25, 35 and 45 minute as time and at 35, 45 and 55 degree centigrade as temperature. Atomic Force Microscopy (AFM), X-Ray Diffraction, and Dynamic Light Scattering (DLS) were used to identify the quantitative and qualitative properties of cellulose nanocrystals. AFM micrographs showed that more severe condition of the treatments decreased the thickness of the cellulose nanocrystals. XRD results also demonstrated that the preparation stages of alpha-cellulose as well as acidic hydrolysis treatments much effectively increased the degree of crystallinity. DLS results indicated that 98.7 percent of the produced nanocrystals under the condition of 55 degree centigrade and 45 minute were in the range of 18-95 ηm, whose highest abundance was in the range of 18-39 ηm. Thus, the mentioned condition were determined as the best and optimum condition for the production of cellulose nanocrystal from cotton stalk cellulose.
