Ali Hasanpoor tichi; Fardad Golbabaei; Mojtaba Rezanezhad
Abstract
In this study, the possibility of making gypsum-based boards from rice straw chips with different levels was investigated. Variable factors in this study were considered in nano at three levels of 0, 3 and 7% and also the ratio of mixing rice straw to gypsum at three levels ( 5:95 , 10:90 , 15: 85 %). ...
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In this study, the possibility of making gypsum-based boards from rice straw chips with different levels was investigated. Variable factors in this study were considered in nano at three levels of 0, 3 and 7% and also the ratio of mixing rice straw to gypsum at three levels ( 5:95 , 10:90 , 15: 85 %). Thus, with the consideration of nine treatments, a total of 27 laboratory boards were constructed. The specific mass of the first target 1.10 gr/cm3 was considered. Mechanical and physical properties of composites include modulus of rupture, modulus of elasticity, internal bonding, water absorption after 2 and 24 hours of immersion, and density of boards according to standard (DIN-EN-634) and fire resistance (weight loss percentage) they were measured according to a standard ISO-11925. In order to investigate the common chapter of rice straw and gypsum as well as the distribution of nano-wollastonite, microscopic images (SEM) of the fracture surface of the samples were prepared and the results showed that the composites made with nano-wollastonite had higher mechanical and physical strengths. Microscopic imaging (SEM) showed that the boards made with 7% nano had stronger internal connections and created a uniform structure. In this study, composites made of 7% nano wollastonite with 5% rice straw were selected as the optimal treatment.
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
Ali Hasanpoor tichi; Behzad Baziyar
Abstract
In this study the effect of nano gel wollastonite usage in three level (0 , 5 and 10 percent per dry by weight of the cement) and the mixture ratios of lingocellulosic material to cement in three level 10:90, 20:80 and 30:70 on physical, mechanical , microscopic and biological properties of composite ...
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In this study the effect of nano gel wollastonite usage in three level (0 , 5 and 10 percent per dry by weight of the cement) and the mixture ratios of lingocellulosic material to cement in three level 10:90, 20:80 and 30:70 on physical, mechanical , microscopic and biological properties of composite made from rice straw fibers- cement was investigated. Three replicates for each treatment and 27 experimental boards were manufactured. Specimens were prepared according to DIN- EN634 standard test methods to measure mechanical and physical properties. Mechanical and physical properties including static bending strength, modulus of elasticity, interior bonding(IB),water absorption after 2 and 24 hours immersion in the water , density and decay resistant (loss weight) were measured. Micro- structural properties of composites were evaluated by SEM images. The results showed that, bending strength , modulus of elasticity , interior bonding and density were significantly increased with increasing Nano gel wollastonite . Also, with increasing Nano gel wollastonite , dimensional stability and decay resistance were increased in comparison with the control sample. Results of scanning electron microscopy showed that the calcium hydroxide formed hydrated calcium silicate gel (C-S-H gel) after addition the Nano gel wollastonite . SEM images showed that the micro- structure of the boards were improved by increasing the nano- wollastonite content.
Composite wood products
Leila Fathi; Mohammad mehdi Faezipoor; Mohsen Bahmani
Abstract
In this investigation the effect of using of UF and MUF Resins on Physical and mechanical Properties of Particleboards Produced from Rice Straw and Aspen Particles has been studied. The aim of this study was to determine of physical and mechanical properties of rice straw– particleboard. ...
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In this investigation the effect of using of UF and MUF Resins on Physical and mechanical Properties of Particleboards Produced from Rice Straw and Aspen Particles has been studied. The aim of this study was to determine of physical and mechanical properties of rice straw– particleboard. Single-layer particleboard was produced. That was produced with 11% MUF and 11% UF. For using of UF and MUF 2% hardener was added to adhesives. The Press condition for MUF was: 1750C for 4 minutes and also for UF application was 1750C for 6 minutes. Another variable factor was the rice straw content in three levels (15%, 30% and 45%). Other factors such as board density (0/7gr/cm3), mat moisture (12%) were constant factors. The results indicate that increasing rice straw to wood particles cause some reduction in modulus of rupture , and internal bonding , and some increase in thickness swelling , and water absorption of manufactured boards. But comparing and grouping means by Duncan test showed that in the most case these effects were insignificant when rice straw add to wood particle up to 30%. Particleboard bonded with 11% MUF had the highest bending strength. Particleboards bonded with MUF had better bending strength, shear strength, thickness swelling and water absorption after 2, 24 hours immersion. Grouping the experimental data while using Duncan method was indicated of the fact that an optimum condition for manufacturing particleboard while using a mixture of rice straw and wood particles is to add 30% rice straw to the mixture , use 11% melamine urea formaldehyde resin and employ a pressing time of 4 minutes.
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
Zahra Ebrahimi; Hossein Kermanian; Omid Ramazani; Majid Zabihzadeh
Abstract
This research was carried out to compare the paper properties from rice straw applying sodium and potassium based Chemimechanical pulping processes. Cooking conditions in potassium based pulping were adjusted as; potassium sulfite 6, 8, 10 and 12%, potassium hydroxide 3, 4, 5, 6, 8 and 12% on oven dry ...
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This research was carried out to compare the paper properties from rice straw applying sodium and potassium based Chemimechanical pulping processes. Cooking conditions in potassium based pulping were adjusted as; potassium sulfite 6, 8, 10 and 12%, potassium hydroxide 3, 4, 5, 6, 8 and 12% on oven dry weight of rice straw, impregnation time; 30 minutes, liquid to rice straw ratio of 7:1, cooking time 30 and 60 minutes and cooking temperature 130, 150, 160, 165 and 170 oC. In sodium- based pulping, cooking conditions were selected as; sodium sulfite 6 and 8%, sodium hydroxide 3 and 4 % on oven dry weight of rice straw, impregnation time 30 minutes, liquid to rice straw ratio of 7:1, cooking time 30 minutes and cooking temperature 130 and 150 oC. The selected treatment in potassium based pulping showed the average total yield of 65.19 and reject of 4.22% and in sodium based pulping showed the average total yield of 69.75 and reject percent of 3.68. After refining the selected pulp to reach the freeness of 300±25 ml CSF, 60 g/m2 hand sheets were made and physical, mechanical and optical properties were measured. Results showed that the tensile strength index, breaking length and apparent density of paper made from potassium based process was similar to paper made from sodium based process. The papers made from potassium based process had higher burst strength index and brightness compared to sodium based process and papers made from sodium based process had higher tear index and higher K/S values than potassium based paper.
Fardad Golbabaei; Hossein Hosseinkhani; Reza Hajihassani; Arash Rashnv
Abstract
The main objective of the production of cement - wood products or mineral-bounded composite panels is to combine the mineral components of lignocellulosic materials such as wood and organic particles with inorganic binders such as cement, plaster, etc. Wood cement products which are presently produced ...
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The main objective of the production of cement - wood products or mineral-bounded composite panels is to combine the mineral components of lignocellulosic materials such as wood and organic particles with inorganic binders such as cement, plaster, etc. Wood cement products which are presently produced in most countries possess desirable functional properties such as good weather ability, resistance to atmospheric, biological agents and fire and are lighter weight as compared with other building materials, and provides improved dimensional stability. The flat panels using conventional presses can be produced, and also other products such as concrete blocks, bricks and pieces of different forms can be produced using appropriate frames. Large wood cement- based panels are widely used in construction of residential and commercial buildings. In this research, with respect to the availability of lignocellulosic material (agricultural residues such as rice straw, wheat straw, cotton stalk) in various areas (Gilan, Mazandaran and Golestan)) and the additive material (as calcium chloride), boards with similar structural was produced. Mechanical strength values including static bending strength, modulus of elasticity and elastic bending strength were measured. MSTATC based computer package was used to analyze the data. In terms of the maximum load strength, wood cement board made of poplar wood as the control boards (4.4146 MPa) had the highest mechanical strength followed by cotton stalks (2.463 MPa), wheat straw (1. 6776 MPa) and rice straw (0. 8622 MPa), respectively. In general, the study has indicated the suitability (given the appropriate ratio) of the agricultural residues in construction of wall and warehouse in farm lands.
Mohammad Tasoji; Amir Nourbakhsh; Abolfazl Kargarfard; Hossein Hosseinkhani
Abstract
Physical and mechanical properties wood-plastic composites produced from wheat and rice straw particles, nano-clay, polypropylene and MAPP were investigated. The amount of polypropylene and lignocellulosic materials were selected as 60 wt% and 40 wt% respectively. The Nano-clay was added in three levels ...
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Physical and mechanical properties wood-plastic composites produced from wheat and rice straw particles, nano-clay, polypropylene and MAPP were investigated. The amount of polypropylene and lignocellulosic materials were selected as 60 wt% and 40 wt% respectively. The Nano-clay was added in three levels 0, 2 and 4 wt% and the amount of coupling agent was fixed and set to 2 wt% for all treatments except for the control. The control samples were made from polypropylene and lignocellulosic materials with neither nanoclay nor coupling agent was used. The results showed that the tensile and flexural strengths were decreased by the addition of nanoparticles. For tensile and flexural modulus, adding 2 wt% of nanoclay led to an increase in both moduli. However there was a decrease in both moduli when 4 wt% nanoclay was added. The impact strength decreased adding nanoclay. There was a decrease in 24 hour water absorption when 2 wt% of nanoclay was added but an increase was observed in 4 wt% of nanoclay level. According to the mechanical and physical properties of all the treatments, the samples made of rice straw showed better results compare to wheat straw samples due to their high amount of silica and its compatibility with nanoclay. SEM test was performed.
Composite wood products
masoudreza habibi; Hossein Hosseinkhani; Saeed Mahdavi
Abstract
In this study, MDF was produced from Rice straw. Variables for Medium Density fiberboard making were as following:
- Resin content 8, 9.5, 11 (percent baced on oven dry weight of fiber)
- Press time (4, 5, 6 minutes).
There were 9 treatment conditions by combinations of the above factors and three ...
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In this study, MDF was produced from Rice straw. Variables for Medium Density fiberboard making were as following:
- Resin content 8, 9.5, 11 (percent baced on oven dry weight of fiber)
- Press time (4, 5, 6 minutes).
There were 9 treatment conditions by combinations of the above factors and three replications for each combinations which resulted in producing 27 boards.The other production variables were constant.
The anatomical properties of Rice straw such as fiber length, fiber diameter were measured respectively 810, 10.1 micron. L/D ratio of Rice straw fiber was measured 80.2. The physical and mechanical properties of MDF were determined according to DIN standard. The measurements of bending properties and IB of MDF revealed that the highest MOR, MOE, IB were obtained in variables combination of 11% resin content and press time of 6 minute and at this conditions thickness swelling of boards were the lowest.
According to Duncans, test method the effects of press times (4 & 5 minutes) and resin content (8% & 9.5%) on bending properties were not significant statistically.
