Iranian Research Institute of Forests and Rangelands

Tehran, Iran

Iranian Research Institute of Forests and Rangelands

Tehran, Iran

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Nourbakhsh A.,Iranian Research Institute of Forests and Rangelands | Ashori A.,Iranian Research Organization for Science and Technology
Bioresource Technology | Year: 2010

This article presents the application of agro-waste materials (i.e., corn stalk, reed stalk, and oilseed stalk) in order to evaluate and compare their suitability as reinforcement for thermoplastics as an alternative to wood fibers. The effects of fiber loading and CaCO3 content on the mechanical properties were also stud- ied. Overall trend shows that with addition of agro-waste materials, tensile and flexural properties of the composites are significantly enhanced. Oilseed fibers showed superior mechanical properties due to their high aspect ratio and chemical characteristics. The order of increment in the mechanical properties of the composites is oilseed stalk > corn stalk > reed stalk at all fiber loadings. The tensile and flexural proper- ties of the composite significantly decreased with increasing CaCO3 content, due to the reduction of interface bond between the fiber and matrix. It can be concluded from this study that the used agro-waste materials are attractive reinforcements from the standpoint of their mechanical properties. © 2009 Elsevier Ltd. All rights reserved.


Ashori A.,Iranian Research Organization for Science and Technology | Nourbakhsh A.,Iranian Research Institute of Forests and Rangelands
Bioresource Technology | Year: 2010

In this work, the effects of wood species, particle sizes and hot-water treatment on some physical and mechanical properties of wood-plastic composites were studied. Composites of thermoplastic reinforced with oak (Quercus castaneifolia) and pine (Pinus eldarica) wood were prepared. Polypropylene (PP) and maleic anhydride grafted polypropylene (MAPP) were used as the polymer matrix and coupling agent, respectively. The results showed that pine fiber had significant effect on the mechanical properties considered in this study. This effect is explained by the higher fiber length and aspect ratio of pine compared to the oak fiber. The hot-water treated (extractive-free) samples, in both wood species, improved the tensile, flexural and impact properties, but increased the water absorption for 24 h. This work clearly showed that lignocellulosic materials in both forms of fiber and flour could be effectively used as reinforcing elements in PP matrix. Furthermore, extractives have marked effects on the mechanical and physical properties. © 2009 Elsevier Ltd. All rights reserved.


Nourbakhsh A.,Iranian Research Institute of Forests and Rangelands | Baghlani F.F.,Iranian Research Organization for Science and Technology | Ashori A.,Iranian Research Organization for Science and Technology
Industrial Crops and Products | Year: 2011

In this research, reinforcing effect of hybrid filler including rice husk (RH), beech bark (BB) and nano-SiO2, in polypropylene has been investigated. In the sample preparation, four levels of filler loading were used for waste lignocellulosic materials (55-58wt.%) and nano-SiO2 (0-4wt.%). In order to increase the interphase adhesion, polypropylene grafted with maleic anhydride was added as a coupling agent to all the composites studied. The physical properties, viz. the thickness swelling and water absorption, and mechanical properties, namely, the tensile, flexural and notched Izod impact strengths, of the composites were determined. Generally, high amount of filler content in composites can lead to the reduction of interfacial adhesion between matrix polymer and filler, and it limits their applications. The results showed that while flexural properties and elongation at break were moderately improved by the increase in the amount of filler in the matrix, tensile and Izod impact strengths decreased dramatically. However, the composites had acceptable mechanical strength levels. The mechanical properties of composites filled with RH are generally greater than BB composites. The thickness swelling and water absorption of the composites increased with the increase in the filler loading, but to a negligible extent as compared with the wood-based composites and the solid woods. Nano-SiO2 addition showed little positive effect on the mechanical properties. It can be concluded from this study that the used waste lignocellulosic materials are attractive reinforcements from the standpoint of their physico-mechanical properties. © 2010 Elsevier B.V.


Ashori A.,Iranian Research Organization for Science and Technology | Nourbakhsh A.,Iranian Research Institute of Forests and Rangelands
Composites Part B: Engineering | Year: 2010

Polypropylene (PP)/microcrystalline cellulose (MCC)/wood flour composites were prepared containing polypropylene-graft-maleic anhydride (PP-g-MA) as compatibilizer. The mechanical, morphological and thermal properties were investigated. The weight ratio of the cellulosic materials to polymer matrix was 40:60 (w:w). The obtained results showed that tensile, flexural and impact strengths of the composites were significantly enhanced with addition of MCC, as compared with pure PP and composites without MCC. The effect of MCC on impact was minimal compared to the effects of PP-g-MA content. Scanning electron microscopy has shown that the composite, with compatibilizer, promotes better fiber-matrix interaction. In all cases, the degradation temperatures shifted to higher values after addition of PP-g-MA. The maximum improvement on the thermal stability of the composites was achieved when 5% PP-g-MA was used. However, the increase in MCC content substantially reduced the thermal stability. This work showed that MCC along with wood flour could be effectively used as reinforcing agent in thermoplastic matrix. © 2010 Elsevier Ltd. All rights reserved.


Nourbakhsh A.,Iranian Research Institute of Forests and Rangelands | Ashori A.,Iranian Research Organization for Science and Technology | Kazemi Tabrizi A.,Islamic Azad University at Karaj
Composites Part B: Engineering | Year: 2014

The objective of this research was to study the potential of waste agricultural residues such as rice-husk fiber (RHF), bagasse fiber (BF), and waste fish (WF) as reinforcing and biodegradable agents for thermoplastic composites. Addition of maleic anhydride grafted polypropylene (MAPP) as coupling agent was performed to promote polymer/fiber interfacial adhesion. Several composites with various polypropylene (PP) as polymer matrix, RHF, BF, WF, and MAPP contents were fabricated by melt compounding in a twin-screw extruder and then by injection molding. The resulting composites were evaluated through mechanical properties in terms of tensile, flexural, elongation at break and Izod notched impact following ASTM procedures. Biodegradability of the composites was measured using soil burial test in order to study the rates of biodegradation of the composites. In general, the addition of RHF and BF promoted an increase in the mechanical properties, except impact strength, compared with the neat PP. According to the results, WF did not have reinforcing effect on the mechanical properties, while it could considerably improve the biodegradation of the composites. It was found that the composites with high content of WF had higher degradation rate. Except impact strength, all mechanical properties were found to enhance with increase in cellulosic fiber loading In addition, mechanical properties and biodegradability of the composites made up using RHF was superior to those of the composites fabricated with BF, due to its morphological (aspect ratio) characteristics. © 2013 Elsevier Ltd. All rights reserved.


Ashori A.,Iranian Research Organization for Science and Technology | Nourbakhsh A.,Iranian Research Institute of Forests and Rangelands
Waste Management | Year: 2010

The main objective of this research was to study the potential of waste agricultural residues such as sunflower stalk, corn stalk and bagasse fibers as reinforcement for thermoplastics as an alternative to wood fibers. The effects of two grades (Eastman G-3003 and G-3216) of coupling agents on the mechanical properties were also studied. In the sample preparation, one level of fiber loading (30 wt.%) and three levels of coupling agent content (0, 1.5 and 2.5 wt.%) were used. For overall trend, with addition of both grades of the coupling agents, tensile, flexural and impact properties of the composites significantly improved, as compared with untreated samples. In addition, morphological study revealed that the positive effect of coupling agent on interfacial bonding. The composites treated with G-3216 gave better results in comparison with G-3003. This could be caused by the high melt viscosity of G-3003. In general, bagasse fiber showed superior mechanical properties due to its chemical characteristics. © 2009 Elsevier Ltd. All rights reserved.


Ashori A.,Iranian Research Organization for Science and Technology | Nourbakhsh A.,Iranian Research Institute of Forests and Rangelands
European Journal of Wood and Wood Products | Year: 2011

In this study, the effects of coupling agent and nanoclay loading on the mechanical properties and water absorption of composites are investigated. Composites based on polypropylene (PP), wood flour, nanoclay, and maleated polypropylene (MAPP) were made by melt compounding and then injection molding. The mechanical analysis showed that the biggest improvement of the tensile and flexural strengths can be achieved for the nanoclay loading at 3%. However, further increasing of the loading of nanoclay resulted in a decrease of all the mechanical properties. The maximum tensile and flexural strengths (increase of ∼46%, compared to the pure PP) were achieved in the composites when 7.5% MAPP was used as coupling agent in the manufacture of the composites. Finally, it was found that addition of nanoclay or MAPP reduced the water absorption property of the composites. However, the extent of improvement in the water absorption is more prominent with MAPP. © 2010 Springer-Verlag.


Kargarfard A.,Iranian Research Institute of Forests and Rangelands | Jahan-Latibari A.,Islamic Azad University
BioResources | Year: 2011

Severe shortage of suitable wood for Medium Density Fiberboard (MDF) production makes it necessary to consider using uncommon and non-conventional raw materials such as agricultural residues. In order to demonstrate the suitability and the potential of two agricultural residues (cotton and corn stalks), laboratory MDF boards were produced. Three press temperatures (170, 180 and 190 °C) were used. Test samples were prepared from the boards after conditioning at 65% RH and 21 °C, and all tests were performed according to relevant EN standard methods. The results indicated that the MOR and MOE of boards produced from corn stalks were higher than those from cotton stalks, by almost 25%. However significant difference was not observed for internal bonds of boards. Thickness swelling of MDF boards from corn stalks was lower than cotton stalks. Comparing the results obtained with the strength of boards produced from hardwoods showed similarity between corn stalks and wood, but the strength of MDF boards from cotton stalks was lower. However, the results almost satisfied the EN 622-5;1997 requirement.


Nourbakhsh A.,Iranian Research Institute of Forests and Rangelands
Journal of Reinforced Plastics and Composites | Year: 2010

Particleboards were produced from three-year-old poplar clones (e.g., Populus euramericana.costanzo, Populus euramericana. 561.41, Populus euramericana triplo, Populus euramericana vernirubensis, Populus euramericana marilandica, Populus euramericana. I-214, Populus deltoides 77.51, Populus trichocarpa, Populus nigra. betulifolia). One-layer laboratory particleboards were made with the above materials, with, board density of 0.7 gr/cm 3, the resin type of (UF), a hardener content of (1%), a hardener type of (NH4Cl), a press pressure of 30 kg/cm2, and a press temperature of 160°C. Modulus of elasticity (MOE) and modulus of rupture (MOR), internal bond strength (IB). Thickness swelling of the specimens were tested according to EN Standard. Overall results showed that most panels made from above materials exceeded the EN Standards for IB, MOE, and MOR. However, thickness swelling (TS) values were higher (poor) than requirements. The highest MOR, MOE, IB were reached with P.e. costanzo, P.e. 561.41, P.e. vernirubensis and P. trichocarpa poplar clones. The lowest TS 2 h and TS 24 h were reached with P.e. 561.41 and I-214 of the three-year-old poplar clones. Most types of panels made in this study covered the MOE, MOR, and IB strength requirements for interior fitments stated in the EN Standards. Nevertheless, the TS of the panels were very poor. Poplar clone panels are suitable for interior decoration (furniture, wall, and ceiling paneling). © 2010 SAGE Publications.


There is a lack of accurate protocol for predicting aboveground biomass (AGB) and carbon pools in Iran's Hyrcanian forests. This study aimed to figure out the most accurate model for the site-specific prediction of AGB. Site-specific allometric equations on the basis of power-law function and artificial neural network (ANN) type of multi-layer perception based on back-propagation training algorithm were developed to model engineering application for predicting the AGB. The AGB was measured by destructively sampling and weighing 174 fallen trees in the field and breast height diameter (D), total height (H) and basic wood density (ρ) were recorded as explanatory variables for developing allometric equations and ANN models. The findings showed that the simple allometry model including the geometrical variable (D2Hρ) was a highly accurate predictor with the highest certainty among the allometric equations (Adj. R2 = 0.91; CF = 1.04; AIC = -430). Furthermore, the product ofD2Hρ and the primary variables were the effective input nodes for training algorithm in the ANN. Statistical issues such as collinearity among the parameters, reliability of parameters and application of dubious empirical equations (...) were the main problems for developing allometric equations; however, there was no limiting factor for designing the models in ANN. According to training and testing data set, the best architecture designed in the ANN model was composed of two hidden layers and 20 neurons in each layer including function of tangent sigmoid. The results showed that the best designed model in ANN predicted the AGB with the higher accuracy (RMSE% = 7.3) than allometric equations. Thus, ANN is offered rather than traditional protocols for predicting the AGB in natural forest ecosystems. © 2016 Elsevier Ltd. All rights reserved.

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