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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.

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
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.

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.

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