Physics and Mechanical Wood
Hamideh Abdolzadeh; Ghanbar Ebrahimi; Mohammad Layeghi; Mehdi Ghasemieh; Seiad Ahmad Mirshokraei
Abstract
In this study, characteristics of wood-polymer fracture under mode I were investigated by double cantilever beam. In this regard, the properties of furfurylated specimens with three different levels of furfurylation (20%, 30% and 65%) were evaluated in both RL and TL systems. Results indicated that load-displacement ...
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In this study, characteristics of wood-polymer fracture under mode I were investigated by double cantilever beam. In this regard, the properties of furfurylated specimens with three different levels of furfurylation (20%, 30% and 65%) were evaluated in both RL and TL systems. Results indicated that load-displacement curves from mode I fracture specimens were changed by furfurylation so that it was much clear on curves of TL system. These changes not only included curve slope in elastic and proportional limit zones, but also fracture zone and initiation of crack growth were included . Furthermore furfurylation and raising its content on both systems and especially on TL one, caused to change in stress intensity factor, KIC , and critical energy release rate , GIC. In both systems GIC were highly increased by increasing of furfurylation contents. This criterion demonstrated that the wood- polymer showed much toughness under mode I fracture. Moreover, variation of KIC values due to furfurylation at both systems was different with that of GIC. At the RL system, ascending trend was observed at KIC and GIC values by increasing furfurylation levels. But at TL system, KIC was decreased by furfurylation and this criterion enhanced by increasing of furan polymer in the cell wall. Generally, results of this research show that fracture toughness of wood is highly affected by furfurylation process
Composite wood products
Aliakbar Aenayati; Halimeh Pangh; Mahammad Layeghi; Kazem Doosthosseini
Abstract
This study was conducted to investigate the effect of Cu nano particles addition on the density profile and mechanical properties of medium density fiberboard. One layer fiberboard (MDF) with the density of 0.58g/cm3and thickness of 17 mm were produced using Cu nano particles in three levels (5, 10 and ...
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This study was conducted to investigate the effect of Cu nano particles addition on the density profile and mechanical properties of medium density fiberboard. One layer fiberboard (MDF) with the density of 0.58g/cm3and thickness of 17 mm were produced using Cu nano particles in three levels (5, 10 and 15wt%based on solid content of resin) and urea formaldehyde resin content in two levels (8 and 10wt%based on oven dry weight of fibers) as variable factors. The control panels were produced using 10% resin (based on oven dry weight of fibers) without Cu nano particles using the identical manufacturing parameters as other panels. Mechanical strength including internal bonding (lB), bending strength, modulus of elasticity and density profile using slicing method were determined. The results indicated that increasing the content of Cu nano-particles had no significant effect on the internal bonding as well as bending strength and modulus of elasticity of panels. Increasing the resin content from 8 to 10 percent improved modulus of elasticity (43.7%), bending strength (18.9%) and internal bonding (23%) of panels. In addition, the increasing Cu nano particles up to 5% caused relatively higher IB for panels produced using 8%resin compared to the control panels(containing10% resin) as well as the density profile was more uniform with the lowest differences between maximum and minimum density in the density profile.
