Mohammad mahdi Mehrandish; Aisona Talaei; Mohammad Hadi Rezvani
Abstract
Flammability is one of the most important parameters that limits the range of wood use. Therefore, it is important to improve the fire retardancy properties of wood. The aim of this study was to evaluate the effect of modification with citric acid and its comparison with borax and ammonium chloride on ...
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Flammability is one of the most important parameters that limits the range of wood use. Therefore, it is important to improve the fire retardancy properties of wood. The aim of this study was to evaluate the effect of modification with citric acid and its comparison with borax and ammonium chloride on the flammability of paulownia wood. Test specimens were prepared and in vitro cylinders were saturated with chemical solutions at 10% depletion. Based on pre-treatment conditions, the modification was performed by heating with oven at different temperature and time levels. The fire performance of the samples was evaluated by measuring different parameters. The effect of different fire retardants on water absorption and short-term swelling of the specimens was also studied. The fire test showed that by treating the samples with citric acid and fire retardant materials, less mass reduction, flame retardation time and longer ignition time were obtained. These findings were attributed to the formation of a protective carbon layer by citric acid and fire retardant materials. The flame retardant properties of borax treatment yielded better results than those using citric acid and ammonium chloride. In addition, water absorption and dimensional stability were improved by the presence of citric acid and fire retardant agents. The results of FTIR spectra showed that the carboxylic acid groups reacted with the hydroxyl groups of the wood and increased the weight of the samples. Changes in the crystallinity indices of cellulose, carbonyl and hydroxyl were also obtained from FTIR spectra.
Chemistry of wood
Mehdi Abdolahi; Said amir Mosavian; Akbar Varamsh; Amin Asadi
Abstract
In this research, two types of lignin, i.e. one extracted from industrial waste water of the Iran wood and paper (choka) factory as black liquor and another provided from Aldrich company, were studied. Firstly, the lignin was precipitated from its black liquor by a dilute acid and was then purified by ...
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In this research, two types of lignin, i.e. one extracted from industrial waste water of the Iran wood and paper (choka) factory as black liquor and another provided from Aldrich company, were studied. Firstly, the lignin was precipitated from its black liquor by a dilute acid and was then purified by dissolving in tetrahydrofuran (THF). Lignin samples were characterized using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1HNMR) spectroscopies. It was found from results that the Aldrich lignin has a structure similar with the lignosulfonate while lignin extracted from black liquor does not have a hydrophilic sulfonate group and has a Kraft lignin structure. Using acetylation of Kraft lignin and complementary characterization with 1HNMR spectroscopy, the ratio of hydroxyl functional groups to methoxy groups was calculated to be 1.11 to 1, and amount of the hydroxyl groups was calculated to be 5.91 mmol/g of acetylated lignin, where 53% of the hydroxyl groups is related to the aromatic hydroxyl groups. By having the molecular weight of the Kraft lignin which was obtained from the gel permeation chromatography (GPC) analysis of the acetylated Kraft lignin to be 1260 g/mol, average number of the hydroxyl groups per acetylated lignin chain was calculated to be 7.44.
Composite wood products
Ahmad Samariha; Habibollah Khademi Eslam
Abstract
Abstract The effect of adding steamed and non-steamed fiber on physical and mechanical properties of the composites made of recycled polypropylene was investigated. Recycled polypropylene was used as a basic matrix at a 57% level, and poplar fibers were used at 180 °C for 1 h at a constant level ...
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Abstract The effect of adding steamed and non-steamed fiber on physical and mechanical properties of the composites made of recycled polypropylene was investigated. Recycled polypropylene was used as a basic matrix at a 57% level, and poplar fibers were used at 180 °C for 1 h at a constant level of 40% in two forms: non-steamed and steamed. The ratio of steamed fibers to non-steamed fibers in composites was 100:0, 50:50, and 0:100, respectively. For all components, the coupling agent was maleic anhydride at a level of 3%. Mixing was done using an internal mixer at 180 °C and 60 rpm, and the samples were constructed by injection molding method. To investigate the effect of steam treatment on the fiber structure and crystallization, X-ray diffraction analysis and FTIR spectra were used. The results showed that the Steaming had no significant effect on resistance. But with steaming increased mechanical properties and physical properties of reduced. Keywords: Composites, Recycled polypropylene, Steamed fiber, XRD, FTIR
Composite wood products
Hassan Ziaei Tabari; Habibollah Khademieslam; Behzad Bazyar; Amir Homan Hemmasi
Abstract
A new kind of thermoplastic elastomer nano composite reinforced with nano cellulose fibers is reported. The first aim of this investigation was to study the interaction and dispersion of nano cellulose fiber into Pebax matrix. This copolymer is Polyether – b – Amide thermoplastic elastomer ...
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A new kind of thermoplastic elastomer nano composite reinforced with nano cellulose fibers is reported. The first aim of this investigation was to study the interaction and dispersion of nano cellulose fiber into Pebax matrix. This copolymer is Polyether – b – Amide thermoplastic elastomer which is synthetized from renewable resources, and its hydrophilic character allows it to interact with nano cellulose. The interaction and reinforcement effect of nano cellulose at 3 levels of nano cellulose (1%, 3% and 5%) were examined by Scanning electron microscopes (SEM), Fourier transform infrared spectroscopy (FTIR) and Mechanical tests (young module, elongation at break and impact resistance). The results achieved from these tests were indicating appropriate effects of nano cellulose fibers for the strong interaction and close contact with polyamide phase of Pebax polymer which caused high mechanical properties (at 3% of nanoellulose) in nano composites. The young module and impact resistance of nano composite were significantly increased.
Composite wood products
Morteza Nazeryan; Vahid Moazemi; Rahim Mohebi gargari
Abstract
The aim of this study was the evaluation of treatment effect of giant reed (Arundo donax) (untreated, heat-treated and hot-water-leached treatment) used in core layer of sandwich panel, and also the effect of weight ratio of almond shell powder to melamine/urea formaldehyde at three levels (3:97, 18:82 ...
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The aim of this study was the evaluation of treatment effect of giant reed (Arundo donax) (untreated, heat-treated and hot-water-leached treatment) used in core layer of sandwich panel, and also the effect of weight ratio of almond shell powder to melamine/urea formaldehyde at three levels (3:97, 18:82 and 33:67 w/w) on the dry- and wet-pull off adhesion (after 2 hours immersion in boiling water) of sandwich panel. Statistical analysis and Duncan multiple range test showed that the type of treatment of core layer particle and the ratio of almond shell powder to melamine/urea formaldehyde statistically influenced the dry and wet-pull off adhesion. According to the FTIR spectra obtained from samples made from particle treated with hot-water, the hot-water treatment caused an increase in number of hydrogen bonds. Macroscopic photos, also, showed that hot-water treatment created the best surface quality in order to forming desirable bond. Generally, panel manufactured from hot-water-treated particles in core layer and 33% of almond shell powder in glue line had the highest pull off adhesion in dry (5.01MPa) and wet (2.86 MPa) conditions.
