Yahya Hamzeh; Shayan Barzagar; Sahab Hadjazi; Soheila Izadyar
Abstract
Mineral fillers are the second most important elements used in papermaking. Increasing filler content in writing and printing papers without decreasing the mechanical properties is always desired for enhancing the optical and printing properties and cost effective papermaking process. In this study, ...
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Mineral fillers are the second most important elements used in papermaking. Increasing filler content in writing and printing papers without decreasing the mechanical properties is always desired for enhancing the optical and printing properties and cost effective papermaking process. In this study, to increase the filler content in paper, calcium silicate was loaded by in situ precipitation on bleached bagasse fibers. The effect of reaction temperature on the loading and precipitation of calcium silicate on fibers was investigated using ash content measurement, XRD spectroscopy, SEM imaging and EDX analysis. Finally, the effect of treated pulp content on the physical and mechanical properties of pulp was investigated. Ash measurement results showed that calcium silicate precipitation in bleached bagasse fibers was achieved and the amount of calcium silicate loading increased with increasing the reaction temperature. XRD spectroscopy confirmed the formation of calcium silicate and calcium carbonate, and their precipitation in cell walls, lumen and interior spaces of the bleached bagasse fibers was confirmed by SEM imaging. The precipitated minerals on the fiber surface consisted of particles with various diameters. The EDX analysis confirmed the presence of silica and calcium in the treated fibers. With the constant basis weight of 80 g/m2, brightness and apparent density increased significantly, however the paper strength decreased by increasing the content of treated fibers in handsheet paper.
Pulp and paper
Kajal Moradian Gilan; Sahab Hedjazi; Ali Abdulkhani; Herbert Sixta
Abstract
In this research, the effect of hot water and alkaline pre-extractions on properties of bagasse monoethanolamine-AQ pulps was investigated and the results were compared with that of soda pulping. The pre-extraction with alkaline charge of 10%, time of 30 min resulted in total yield and holocellulose ...
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In this research, the effect of hot water and alkaline pre-extractions on properties of bagasse monoethanolamine-AQ pulps was investigated and the results were compared with that of soda pulping. The pre-extraction with alkaline charge of 10%, time of 30 min resulted in total yield and holocellulose of 94.7% and 71.6%, respectively. The hot water pre-extraction with L/W of 10/1 and time of 45min lead to total yield and hollocellulose of 94% and 69.4%, respectively. These trails were selected as the optimum conditions. Monoethanolamine was used as pure and also in different proportions with water for cooking unextracted and pre-extracted bagasse. Variables in monoethanoleamine pulpng were ratio of monoethanolamine to water at three levels (100/0, 75/25, and 50/50%) and the ratio of the liquor to bagasse of 6 to 1, cooking time of 60 min, the temperature of 165°C and AQ charge of 0.1% considered as constant. According to the results, the MEA-AQ pulps produced with MEA/H2O ratio of 75/25 (from unextracted bagasse) have the highest total yield (61.9 %) and the acceptable kappa number (19.5). Pre-extraction resulted in improving of the yield in both MEA-AQ and soda pulping processes. After pre-extraction, the tensile index and breaking length of pulps dropped. In contrast, the tear index of pulps produced from pre-extracted bagasse in both pulping processes was increased. The brightness of soda pulps from un- and pre-extracted bagasse was more than that of MEA-AQ pulps. After pre-extraction, the opacity of pulps remains almost unchanged.
Chemical conversion
Atefe Rahimi; Ali Abdolkhani; Yahya Hamzeh; Sahab Hedjazi
Abstract
DOR:98.1000/1735-0913.1398.34.124.66.1.9.1580 Rice straw rice is one of the most important lignocellulose wastes in Iran and the world. In this research, rice straw as renewable lignocellulosic materials were used to produce nano-structural lignocellulosic aerogel. For this purpose, rice straw powder ...
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DOR:98.1000/1735-0913.1398.34.124.66.1.9.1580 Rice straw rice is one of the most important lignocellulose wastes in Iran and the world. In this research, rice straw as renewable lignocellulosic materials were used to produce nano-structural lignocellulosic aerogel. For this purpose, rice straw powder was first pre-treated in sodium hydroxide aqueous alkali solution and resulting gel form mixture was transformed into physically bonded lignocellulosic porous and ultra-lightweight aerogel through consecutive processes including freezing-thawing, solvent exchange and freeze-drying. The product properties including apparent density and total porosity were determined, and other physical and chemical properties were evaluated by SEM, FTIR, XRD, nitrogen absorption (BET) and DSC methods. The results showed that a significant amount of the rice straw compounds dissolved in aqueous alkali solution and removed during the subsequent stages of aerogel production. The resulting aerogel showed a nano dimensional structure composed of particles and interconnected nanofibers, which had a great chemical and physical difference from the original rice straw.
Composite wood products
Behzad Ghasemi; Farshid Faraji; Sahab Hedjazi
Abstract
Abstract In this research, the effect of using natural poly lactic acid polymer and the amount of MAPP coupling agent on the physical and mechanical properties of composite manufactured by sunflower stem flour was studied. For this purpose, three levels of PLA polymer including 50, 60 and 70% and tow ...
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Abstract In this research, the effect of using natural poly lactic acid polymer and the amount of MAPP coupling agent on the physical and mechanical properties of composite manufactured by sunflower stem flour was studied. For this purpose, three levels of PLA polymer including 50, 60 and 70% and tow levels of MAPP including 4 and 6 percent based on dry weight of polymer were used as variables. Then, the physical and mechanical properties of the test specimens including dimensional stability, resistance and tensile modulus, resistance and flexural modulus and impact resistance were measured. The results showed that increasing the amount of PLA polymer and reducing the share of sunflower stem flour and increasing MAPP up to 6 percent, increased the flexural, tensile and impact resistances and improved dimensional stability of the composites. But in contrast, the tensile and bending modulus of composites were reduced. However, by reviewing the results, it was found that the physical and mechanical properties of the composites made with this polymer and the particles of sunflower stem flour were competitive with other composites made with other chemical polymers and in some cases it was better than them.
Composite wood products
Laya Jamalirad; Fereshteh Kor; Farshid Faraji; Sahab Hedjazi
Abstract
In this research, the manufacture of particleboard using lignocellulosic residues including wheat straw and tobacco stalks mixed with industrial wood chips were studied. The variable factors included the mixture of wheat straw and tobacco stalks with industrial wood chips in four levels 0/100, 20/80, ...
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In this research, the manufacture of particleboard using lignocellulosic residues including wheat straw and tobacco stalks mixed with industrial wood chips were studied. The variable factors included the mixture of wheat straw and tobacco stalks with industrial wood chips in four levels 0/100, 20/80, 40/60 and 60/40 (In any combination, according to the desired levels, tobacco stalks and wheat straw were used equally) and the amount of urea formaldehyde resin was at two levels 12 and 14% of the dry weight of the wood chips. The results showed that by increasing the mixture of wheat straw and tobacco stalk up to 60 percent, the physical and mechanical properties of the boards decreased significantly. But increasing the amount of adhesive consumption up to 14 percent had a positive impact on the physical and mechanical properties of the boards and improved internal bonding, bending strength and modulus of elasticity and dimensional stability of the boards. It means that by increasing the use of this type of wastes up to 40 percent with an increase in the amount of UF adhesive up to 14% can be produced the boards with the mechanical properties at standard level.
Pulp and paper
Mohammad Ahmadi; Sahab Hejazi; Kamiar Salehi
Abstract
In this study, the effect of beating time on morphologic, physical and strength properties of soda and monoethanolamine pulps obtained from wheat straw was studied, in order to optimize the time for beating operation. Beating of the pulps was applied in different time by laboratory jokromill beater. ...
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In this study, the effect of beating time on morphologic, physical and strength properties of soda and monoethanolamine pulps obtained from wheat straw was studied, in order to optimize the time for beating operation. Beating of the pulps was applied in different time by laboratory jokromill beater. The results showed that rising time of beating leads to increasing the freeness (SR) of pulps and monoethanolamine pulp reached to maximum amount of freeness (SR) in less time as compared to soda pulp. In addition, it is found that monoethanolamin pulp obtained the maximum amount of tensile index (91.3 N.m/g) after 30 min beating time and after that longer time of beating process had no significant effect on increasing the tensile index. About soda pulp it is observed that tensile index was increased significantly by rising the time of beating process and for this kind of pulp, maximum amount of tensile index (87.7N.m/g) was obtained in 50 min beating process. The highest burst index for soda pulp was 5 Kp.m2 which was obtained by 50 min beating process. About mono ethanolamine pulp burst index increased by rising time of beating Process and reached to its maximum amount (5.6 Kp.m2) and after that its amount decreased. Rising the time of beating process led to decreasing the tear index in both of kinds of pulp consist of monoethanolamin and soda pulp. The results showed that mono ethanolamine pulp had the higher yield and better beating ability in comparison with soda pulp which can be caused by better ability for carbohydrates and minerals retaining in monoethanolamin pulp.
Composite wood products
Samira Brzali; Laya Jamalirad; Farshid Faraji; Sahab Hejazi
Abstract
In this research with the aim of using a natural component, renewable and environmentally friendly which is not environmental pollution, the physical and mechanical properties of plywood manufactured by populous with urea formaldehyde resin and silk cocoon were studied. For this purpose, silk cocoon ...
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In this research with the aim of using a natural component, renewable and environmentally friendly which is not environmental pollution, the physical and mechanical properties of plywood manufactured by populous with urea formaldehyde resin and silk cocoon were studied. For this purpose, silk cocoon was used as filler and reinforcement for four levels of 0, 10, 20 and 30 percent according to dry weight of urea formaldehyde resin. The physical and mechanical properties of samples including water absorption and thickness swelling after 2 and 24 hours immersion in water, bending strength parallel and perpendicular to the surface layer grain and shear strength were measured. The results show that increasing the amount of silk cocoon, decreased water absorption and thickness swelling after 2 and 24 hours immersion in water and increased bending strength parallel and perpendicular to the surface layer grain and shear strength. So that, using 30 percent of silk cocoon, dimensional stability, bending strength and shear strength, were improved.
Composite wood products
Alireza Beiazyat; Laya Jamalirad; Hedayat alah Aminian; Sahab Hejazi
Abstract
In this research, the effect of the wood filler content and coupling agent (MAPP) on the physical and mechanical properties of Polypropylene reinforced with palm wood flour from the annual pruning of palm leaves (Shahani species) composite, were studied. For this purpose, the palm wood flour in three ...
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In this research, the effect of the wood filler content and coupling agent (MAPP) on the physical and mechanical properties of Polypropylene reinforced with palm wood flour from the annual pruning of palm leaves (Shahani species) composite, were studied. For this purpose, the palm wood flour in three levels of 30%, 40%, 50% and two levels of Maleic anhydride grafted polypropylene 4% and 6% were used as variable factors. Then, the Physical and mechanical properties of samples, including thickness swelling after 2 and 24 hours of immersion in water, bending strength, bending modulus, tensile strength, tensile modulus and impact strength, were measured.The results showed that by increasing palm wood flour, the bending strength, tensile strength and impact strength were decreased but the thickness swelling, bending modulus, tensile modulus were increased. It was also found that by adding MAPP, thickness swelling, bending strength, bending modulus, tensile strength and tensile modulus were improved. The results revealed that at increased consumption of palm wood flour and adding coupling agent leads to improve quality of the interface and significant changes especially dimensional stability and MOE, are achieved.
Composite wood products
Alireza Sokhtesaraei; Sahab Hejazi; Laya Jamalirad; Mohammad Ahmadi; Sead behnam Hosseini
Abstract
In this study, the physical and mechanical properties of polypropylene composites reinforced with alkaline sulfite-anthraquinone, soda-anthraquinone and monoethanolamine-anthraquinone and chemical mechanical produced from non-extrated and pre-extracted bagasse with hot water were studied. MAPP coupling ...
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In this study, the physical and mechanical properties of polypropylene composites reinforced with alkaline sulfite-anthraquinone, soda-anthraquinone and monoethanolamine-anthraquinone and chemical mechanical produced from non-extrated and pre-extracted bagasse with hot water were studied. MAPP coupling agent (3%) was added and the performance of pretreated and unpretreated bagasse composites were compared. The ratio of the polypropylene and reinforcement material (pulp) was considered at 50/ 50 (w/w). The results showed that the pulping process has a significant effect on all physical and mechanical properties of produced composites. In general, composites containing chemical pulps showed greater dimensional stability and mechanical strengths but lower water absorption than that of mechanical pulp. Composites containing treated fibers with alkaline sulfite-anthraquinone and soda pulp had the highest mechanical properties and dimensional stability. Composites made from fibers in which hemicelluloses were extracted and then were treated with chemical pulping processes had the highest mechanical strength and dimensional stability among all of samples. The highest mechanical strengths and dimensional stability were observed in composites which were reinforced with treated fibers compared with control samples containing untreated bagasse fibers. In general, the results showed the superior physical and mechanical characteristics for pulp - plastic composites compared with wood flour plastic composites.
Pulp and paper
Saleh Ghahrmani; Sahab Hejazi; Saeid Mahdavi
Abstract
In this research, capacity of cellulose nanofibers to reinforce of high yield kraft pulp produced (HYKP) from Populus deltoides clone 69-55 for making unbleached top kraft liner (UTKL) was investigated. The variable conditions of cooking were included the cooking time and temperature each one in two ...
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In this research, capacity of cellulose nanofibers to reinforce of high yield kraft pulp produced (HYKP) from Populus deltoides clone 69-55 for making unbleached top kraft liner (UTKL) was investigated. The variable conditions of cooking were included the cooking time and temperature each one in two levels. Sulfidity and active alkali were constant in the all cooking and liquid to wood ratio was 4 to 1. Optimum pulp was selected according to the pulp yield and kappa no. to reinforce by cellulose nanofiber. Then, it was refined by PFI mill beater to achieve 385 ml. CSF. The cellulose nanofiber was added in three levels (5, 10 and 15%) to HYKP, then mixed for 5 min. and handsheet made by special wire. The result indicated that 15% adding of cellulose nanofiber to high yield kraft pulp increased tensile index by 39%, burst index by 33%, tear index by 17.7%, bending stiffness index by 38% and ring crush tests (RCT) by 55.47%, respecting to the HYKP. In overall, it is recommended nanofiber adding to HYKP for UTKL making according to the yield and also physical and strength of reinforced pulp.
Pulp and paper
Farzaneh Shiralizadeh; Sahab Hejazi; Mohammad Ahmadi
Abstract
In this research, rice straw was used as raw material. Potassium hydroxide was combined with monoethanolamine (MEA) as liquor. In another processes NaOH/Na2So3, KOH/K2So3 and KOH 14% was used as references pulp. The results showed that using pure MEA(15%) produced the highest yield and the highest kappa ...
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In this research, rice straw was used as raw material. Potassium hydroxide was combined with monoethanolamine (MEA) as liquor. In another processes NaOH/Na2So3, KOH/K2So3 and KOH 14% was used as references pulp. The results showed that using pure MEA(15%) produced the highest yield and the highest kappa number. By using potassium hydroxide as a additive agent in MEA pulping, the amount of reject, yield and kappa number was decreased and the lowest yield and the lowest kappa number relevant to MEA(15%) combined with KOH (40%). In addition, in KOH pulping observed that, with increasing concentration of MEA, as additive agent, the amount of total yield increased but the kappa number and reject content was decreased. Results showed that the highest tensile index and tear index were relevant to MEA (15%) combined with KOH (20%) and the highest burs index relevant to NaOH/Na2SO3 treatment. According to the optical properties, it was found that the highest brightness was achieved in K2SO3/KOH. The highest opacity relevant to the KOH14% .The result shows that MEA process in combined with Potassium hydroxide can be done success fully on rice straw and properties of pulp production, specially in aspect of mechanical strength, in term of combination is superior than soda and Potassium hydroxide process
Pulp and paper
Hadi Hasanjanzadeh; sahab hejazi; saeed mahdavi
Abstract
In this study, rice straw as an abundant and cheap raw material selected to produce soda - anthraquinone pulp. Nano fiber Cellulose of rice straw were added to improve the pulp strength after cationing. Cationed suspension was mixed at three levels including 2, 5 and 10 percent with nano fiber cellulose. ...
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In this study, rice straw as an abundant and cheap raw material selected to produce soda - anthraquinone pulp. Nano fiber Cellulose of rice straw were added to improve the pulp strength after cationing. Cationed suspension was mixed at three levels including 2, 5 and 10 percent with nano fiber cellulose. Starch and polyacrylamide as cationic chemicals were used to stabilize nano fiber cellulose at 1.5% and 0.2% based on oven dried pulp, respectively. The result showed that there is linear change between stock drainage time and paper strength according to nano fiber cellulose added content. Tensile and burst index were improved at 18.66% and 18.12% respectively by adding 10% of nano fiber cellulose to suspension treated with cationic polyacrylamide. Furthermore, the two indices increased until 19.35% and 19.24% by adding of maximum amount of nano fiber cellulose (10%) to cationed pulp suspension with cationic starch, respectively. The use of nano fiber cellulose had a positive significant effect on paper properties.
Pulp and paper
Mohammad Ahmadi; Mohammad mehdi Faezipoor; Ahmad Jahan latibari; Sahab Hejazi
Abstract
Neutral sulfite semi chemical pulping of Canola residues has been investigated. Canola residues collected from research farm at Agriculture and Natural Resources, University of Tehran, in Karaj. Chemical composition of Canola residues including cellulose, lignin, extractives soluble in ethanol-acetone ...
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Neutral sulfite semi chemical pulping of Canola residues has been investigated. Canola residues collected from research farm at Agriculture and Natural Resources, University of Tehran, in Karaj. Chemical composition of Canola residues including cellulose, lignin, extractives soluble in ethanol-acetone and ash were determined using relevant TAPPI standard test methods. Fiber dimensions of Canola residues were also measured. Then neutral sulfite semi chemical pulps were produced from Canola residues applying following conditions: Cooking time at 3 levels(20,40,60min),chemical charge at 5 levels(8,10,12,14,16 %), Cooking temperature was kept constant for all cooks at 175ċ , Na2SO3 to Na2CO3 ratio was 3:1,and liquor to Canola residues at 8:1. Each pulping was repeated tree times. At the end of each cooking, initial defibration was carried out using a laboratory disc refiner. Total yield before defibration and yield after defibration and screened yield were determined. The highest yield (72%) was obtained at treatment combination of and the lowest yield (58.7%) was in treatment of .Both factors, time and chemical charge, had significant effect on yield and increasing these two factors caused lower yield.
