mona shayestehkia; Habibollah Khademi Eslam; Behzad Baziyar; Hossein Rangavar; Hamid Reza Taghiyari
Abstract
Abstract In this research, the effect of cellulose nanocrystals on the functional properties of wood cement composite panels has been investigated. Variable factors in this research are the percentage of nano in (five levels of 0, 0.1, 0.2, 0.5 and 1%), the weight of cement and also the ratio of mixing ...
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Abstract In this research, the effect of cellulose nanocrystals on the functional properties of wood cement composite panels has been investigated. Variable factors in this research are the percentage of nano in (five levels of 0, 0.1, 0.2, 0.5 and 1%), the weight of cement and also the ratio of mixing wood chips with cement in three levels (1 to 3, 1 To 3.5 and 1 to 4) dry weight of cement. In this research, poplar wood and Portland cement type 2 have been used as fixed agents. In total, 15 treatments and 3 replicates of each treatment were made. Preparation of sample in accordance with the standard (DIN / EN 634) and measurement of physical and mechanical properties including flexural modulus, modulus of elasticity in accordance with the standard (DIN / EN 310), internal adhesion in accordance with the standard (DIN / EN 319), thickness swelling after 2 and 24 hours of immersion in water was performed according to the standard (DIN / EN 317). Increased cellulose nanocrystals improved physical and mechanical strength. SEM microscopic images were taken from the samples to examine the microstructural properties of the composite. In the pictures, it was found that by adding cellulose nanocrystals, we see an improvement in the disintegration of nanocomposite materials and as a result, an increase in mechanical and physical properties
Composite wood products
Hadi Ashtari; Mehdi Jonoobi; Maryam Yousefzadeh; Yahya Hamzeh
Abstract
In this study Poly vinyl alcohol (PVA) and cellulose nanocrysrals (CNC) composite nanofibers were prepared by electrospinning process. To dissolve PVA, the deionized water was used due to environmental friendly of PVA. The design of experiments (DOE) was done by the Taguchi method using the Minitab for ...
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In this study Poly vinyl alcohol (PVA) and cellulose nanocrysrals (CNC) composite nanofibers were prepared by electrospinning process. To dissolve PVA, the deionized water was used due to environmental friendly of PVA. The design of experiments (DOE) was done by the Taguchi method using the Minitab for optimization of electrospinning. Polymer concentration was determined in 4, 6, 8 and 10% by solvent weight. Bead-free fibers were produced in 8% PVA concentration. CNC were added to polymer in 0.5, 1, 1.5 and 2% by PVA weight and DOE was applied for Needle to collector distance (cm), polymer concentration (%), polymer feed rate (mh/hr.) and applied voltage (Kv) were defined as variables, again to reach the thinnest fibers. Nanocomposites were soaked in GA 50% concentration for 48 hrs. to prevent nanocomposites decomposition. SEM and FESEM were used for morphological characterization. Diameter of the fibers was analyzed by Image software. Tensile, Modulus of Elasticity (MOE), Tension, Porosity, swelling and dissolving of nanocomposites were examined. Chemical reactions were traced by FTIR. Fibers with 87±16 nm in diameter were achieved in 0.5% CNC, 22 KV, 0.3 ml/hr. and 20 cm. Swelling and and solubility of nanocomposites were significantly improved by GA. FTIR spectra shows hemiacetal bounds produced during GA soaking. MOE and tensile were improved by CNC addition meanwhile tension and porosity were decreased. Same results were obtained for GA soaked nanocomposites.
Management and Economics wood
Azar Haghighi Poshtiri; Mehdi Jonoobi; Ali Naghi Karimi
Abstract
Cellulose nanocrystals (CNC) are new class of cellulose materials that find wide applications in various research areas over the past two decades. These nanoparticles are usually made by acid hydrolysis of cellulose substances such as wood, cotton, Starch etc. The main aim of this study is to find the ...
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Cellulose nanocrystals (CNC) are new class of cellulose materials that find wide applications in various research areas over the past two decades. These nanoparticles are usually made by acid hydrolysis of cellulose substances such as wood, cotton, Starch etc. The main aim of this study is to find the optimal conditions for obtaining an aqueous stable colloid suspension of cellulose nanocrystal (CNC) from α-cellulose with a high-yield procedure. Therefore various conditions of acid hydrolysis were evaluated as reaction temperature and reaction time. The percentage of yield was calculated for all suspensions. The morphology of the prepared CNC was characterized by Transmission Electron Microscopy (TEM), Environmental Scanning Electron Microscopy (ESEM) and the crystallinity was measured by X-ray diffraction (XRD). The results showed that highest yield of CNC (88%), was achieved from the reaction condition of 60 minutes at 60 °C. Generally, rod-like shape crystals achieved from α-cellulose with an average size of 35-50 nm and high crystallinity (92%) can be make it to a convenient and competitive source for the production of cellulose nanocrystal for various industries.
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.
