PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 7, Number 1, 2021
“ Natural based polyurethane matrix composites reinforced with bamboo fiber waste for use as oriented strand board ”, Mariana Dias Machado Lopes, Magno de Souza Pádua, Juliana Peixoto Rufino Gazem de Carvalho, Noan Tonini Simonassi, Felipe Perissé Duarte Lopez, Henry A. Colorado & Carlos Maurício Fontes Vieira, Journal of Materials Research and Technology , 12, May – June 2021, 2317-2324. Composites that use natural fibers as reinforcement have generated great interest in the industrial and scientific community due to the need for materials that present environmental responsibility and are economically viable. This work aimed to develop and establish a comparative analysis of the mechanical properties and physical characteristics between a castor oil based polyurethane resin composites reinforced with fibrous bamboo residue and a commercial Oriented Strand Board (OSB), in which where determined the technical issues of using these composites as OSB panels. Bamboo fibers used were obtained as a residue from a barbecue sticks industry. Composites were made with 20 and 40% volume fraction of continuous and aligned bamboo fiber. The density, moisture absorption, and mechanical strength of the composites were tested and compared with the commercial OSB. The composites not only presented mechanical performance superior to the commercial OSB, surpassing 1000 J/m, 85 MPa and 4.4 GPa for impact resistance, flexural strength, and flexural elastic modulus, respectively, but also fulfilled the standard requirements, while the commercial OSB, failed in most of the observed standards criteria. In addition, the developed materials contribute to a sustainable environment by using both bamboo waste and castor oil based polyurethane resin in a composite material. “ Effects of shear deformation and orthotropy on the buckling behaviour of oriented strand boards ”, Stanley Emeka Iwuoha & Werner Seim, Wood Material Science & Engineering , online March 2021. The literature is replete with studies conducted on wood-based boards. However, studies involving the influence of orthotropy and shear deformation on the one-dimensional buckling behaviour of oriented strand boards are lacking. This study is a step-by-step approach towards investigating and discussing the influence of orthotropy and shear deformation on the bending and one-dimensional buckling behaviour of oriented strand boards using specimens which are 12, 18, and 25 mm in thickness, measuring 400 and 780 mm in length for the bending analyses and 400, 425, 450, 475, and 500 mm for the buckling analyses. FE-models were developed which considered the boards as orthotropic and were able to determine their load-displacement behaviour considering the effects of geometric non-linearities. Results of the analyses showed that orthotropy have significant effects on the bending while shear deformation influences both the bending and buckling behaviour of oriented strand boards. In bending, the effects are generally higher in the main strength than in the secondary strength direction. In buckling, it is a reduction in the buckling loads in a range of between 4% and 26%, compared to what would have been obtained using the Euler equation. An alternative Equation with a better ability to predict the one-dimensional buckling load of wood-based boards was presented and discussed.
Technical Abstracts
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