Sima Sepahvand; Mehdi Jonoobi; Alireza Ashori
Abstract
The applications of renewable nanomaterial’s, such as cellulose nanofibers (CNFs), have recently been of great interest due to their unique properties, including high surface area, high aspect ratio, biodegradable, easy access and reactive hydroxyl groups on the surface. The purpose of this study ...
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The applications of renewable nanomaterial’s, such as cellulose nanofibers (CNFs), have recently been of great interest due to their unique properties, including high surface area, high aspect ratio, biodegradable, easy access and reactive hydroxyl groups on the surface. The purpose of this study was to fabricate refined air nano filters using phthalimide- modified CNFs. Because phthalimide contains amine groups that are needed to adsorb carbon dioxide. In this study, a freeze drying method was used for direct removal of water from pure CNFs gel and phthalimide -modified. Also, the properties of pure CNFs aerogels and phthalimide-modified (containing amine groups) were investigated to adsorption carbon dioxide. Modification of CNFs with phthalimide in 4% (v/v) acetic acid, with ratios of CNFs to phthalimide 1: 0, 1: 0.5, 1: 1 and 1: 1.5 wt %. Chemical properties and morphology of modified CNFs were investigated using various techniques including SEM, FTIR-ATR, XRD and TGA. Based on the results, the SEM test did not show any change in the size and structure of the modified CNFs. The presence of phthalimide was confirmed by the creation of new pitches NH2, C-N and ester 〖COO〗^- on modified CNFs using the ATR-FTIR spectroscopy test. Also, the results of TGA indicated that increasing the amount of phthalimide reduces the thermal stability, indicating the reactivity of the functional groups of phthalimide with CNFs. In addition, the highest carbon dioxide adsorption of 1.5% phthalimide was about 50%.
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.
Nazanin Motie; Mehdi Jonobi; Mohammad Mehdi Faezipour; Assunta Borzacchiello
Abstract
This study was focused on the preparation of an environmentally friendly nanocellulose based hydrogel in the form of pads. Hydrogels are hydrophilic three dimensional network with crosslinks, swells in water but don’t dissolve. In this research nanofibrillated cellulose and Hydroxyethyl cellulose ...
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This study was focused on the preparation of an environmentally friendly nanocellulose based hydrogel in the form of pads. Hydrogels are hydrophilic three dimensional network with crosslinks, swells in water but don’t dissolve. In this research nanofibrillated cellulose and Hydroxyethyl cellulose with different ratio (1:1, 2:1, 3:1) were used to make hydrogel. Also, citric acid which has a significant advantage over other crosslinking agents in terms of toxicity and price, has been used in different amounts of 10% and 20% by weight to crosslink. In order to find optimal hydrogel preparation conditions, FTIR analysis, FESEM, time dependent swelling measurement and evaluating the thermal and rheological properties were performed. Samples with a lower ratio of nanocellulose to hydroxyethyl cellulose were found to be inappropriate due to the loss of their apparent integrity in the swelling measurement. According to FTIR results, cross-linking were performed only in samples with the highest ratio of nanocellulose to hydroxyethyl cellulose in different amounts of citric acid. Therefore, the hydrogels' characteristics were mainly influenced by the ratio of nanocellulose to hydroxyethyl cellulose and the amount of citric acid had less effect on these properties. These two successful final samples showed acceptable properties in other evaluated properties and led to the selection of optimal reactive ratios for the preparation of hydrogels for use in various industries, including the pharmaceutical industry.
Composite wood products
Shoboo Salehpour; Mehdi Jonobi; Masoud Ahmad Zadeh; Fatemeh Rafieian
Abstract
The biodegradability of cellulose nananofiber-PVA nanocomposites were studied under controlled composting conditions and the quality of the compost was evaluated. The nanocomposite based on PVA with 5, 10, 20 and 30 wt % of CNF was prepared by using liquid nitrogen and freeze drying techniques. Specimens ...
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The biodegradability of cellulose nananofiber-PVA nanocomposites were studied under controlled composting conditions and the quality of the compost was evaluated. The nanocomposite based on PVA with 5, 10, 20 and 30 wt % of CNF was prepared by using liquid nitrogen and freeze drying techniques. Specimens were buried in compost obtained from municipal solid waste of a compost Factory, Karaj municipality, Iran, for 150 days. The biodegradability of materials was assessed by calculation the visual observation, weight loss, scanning electron microscopy (SEM) and chemistry and transparency (FTIR). The ecotoxicological impact of compost samples was evaluated via plant growth tests with cress and spinach. Biodegradation studies of the films during municipal solid waste confirmed that the biodegradation time of PVA/CNF films greatly depends on the CNF content. The SEM analysis showed that the biodegradability of the films at surface of the samples (deep pores and cracks) was increased with increased the CNF content. By considering the ecotoxicological test using plants growth, it seems that all nanocomposite and pure PVA did not generate a negative effect on germination or development of the vegetal species.
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.
Management and Economics wood
Mehdi Jonobi; Shabo Salehpoor; zhreh Araaznia; Yahya Hamzeh
Abstract
This study was carried out to investigate the effect of storage time on the color and chemical compounds of bagasse particleboard made. For this purpose, the three levels of stored and fresh bagasse from karoon particleboard Company were used. In addition, the chemical compositions ...
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This study was carried out to investigate the effect of storage time on the color and chemical compounds of bagasse particleboard made. For this purpose, the three levels of stored and fresh bagasse from karoon particleboard Company were used. In addition, the chemical compositions were determined according to the TAPPI test methods and also biometrical (slenderness ratio) was done using the fiber dimension measured by Franklin method. The results showed that the amount of lignin was different in the stored samples at three levels, but the difference in the amount of cellulose and extractive was not observed. The results illustrated that the color changes in the stored bagasse were more than fresh sample. Identification of the microorganisms in stored samples was done and results showed that most of microorganisms were bacteria and yeast. The results showed that the storage time can significantly effect the color and physical properties of stored bagasse.
