soheila izadyar; Roghayeh Hamzezadeh; Davood Efhamisisi
Abstract
The aim of this study was to investigate the effect of poplar wood saturation with nano-wollastonite and nano-wollastonite-styrene mixture on fire resistance and mechanical properties of polymer wood. Populus deltoids with 4% nano-wollastonite and 75% methanolic solution of styrene monomer was saturated ...
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The aim of this study was to investigate the effect of poplar wood saturation with nano-wollastonite and nano-wollastonite-styrene mixture on fire resistance and mechanical properties of polymer wood. Populus deltoids with 4% nano-wollastonite and 75% methanolic solution of styrene monomer was saturated by vacuum-pressure method. Four different wood treatments with nano-wollastonite, styrene, simultaneous nano-wollastonite and styrene (one-step) by 1:1 ratio and finally, the initial wood saturation by nano-wollastonite and then styrene (two-stage treatment) were investigated. In this study, the fire resistance and mechanical properties of the specimens were investigated. The results showed that the weight loss of wood against fire in two-stage treatment (NW+St) was 61.38% and in one-stage treatment (NW/St) was 69.68% better than control. NW/St treatment flame durability was approximately equal to NW treatment and improved by 30% compared to control. The reduction of carbonized area in two-stage (NW+St) and one-stage (NW/St) treatments was 28.53% and 29.06%, respectively, which showed a significant decrease. The results of mechanical tests showed that the NW/St treatment had the highest value due to the presence of condensing material in parallel to the NW/St treatment which showed an increase of 57.41% compared to the control sample. The modulus of elasticity and disruption of NW/St treatment increased by 26.77% and 35.71%, respectively. In addition, resistance to hardness of NW/St treatment increased by 10.07% compared to control. Overall, it can be concluded that mixing nano-wollastonite with styrene, while increasing the polymer wood fire resistance, also improved the mechanical properties of the polymer wood.
Management and Economics wood
Aisona Talaei; Mohammad Hadi Rezvani
Abstract
In this research the effect of chemical modification with Polycrease ECR on the functional performance of poplar wood to use as wood polymer were investigated. Polycrease ECR the modified dimethyloldihydroxy-ethyleneurea (DMDHEU) was used for chemical modification of wood by impregnation method. Specimens ...
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In this research the effect of chemical modification with Polycrease ECR on the functional performance of poplar wood to use as wood polymer were investigated. Polycrease ECR the modified dimethyloldihydroxy-ethyleneurea (DMDHEU) was used for chemical modification of wood by impregnation method. Specimens prepared according to the ASTM standard and treated in two levels of 30 and 50%. Modification process of specimens were performed at 24 hours in temperature of 120°C. Functional performance including Weight percent gain (WPG), bulking, long term water absorption and volumetric swelling in 8 weeks, bending strength (MOR) and modulus of elasticity (MOE), compression strength parallel to the grain, shear strength and withdrawal resistance of screw parallel to the grain was measured. Two-way analysis of variance (ANOVA) was used for statistical analysis. Obtained results of modified specimens were compared with untreated control. Results showed that modification with Polycrease ECR had significant effects on physical and mechanical properties in treated specimens. Chemical modification in 30% level, lead to reduce long term water absorption and volumetric swelling. Reduction in mechanical properties were not considerable. Chemical modification with Polycrease ECR in 30 % level compared to 50 % level, showed better physical and mechanical properties. Generally, influence of chemical modification on the physical properties (long term water absorption and volumetric swelling) were dominant.
Management and Economics wood
Elham Hatamzadeh Arabi; Maryam Ghorbani; Prya Biparva
Abstract
The current research work was planned to investigate the possibility of zinc oxide nanoparticles synthesis using hydrothermal method in wood structure and its effect on mechanical and biological properties of wood-polymer composite. Test samples were divided to control and treated with styrene, zinc ...
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The current research work was planned to investigate the possibility of zinc oxide nanoparticles synthesis using hydrothermal method in wood structure and its effect on mechanical and biological properties of wood-polymer composite. Test samples were divided to control and treated with styrene, zinc oxide nanoparticles, nanocomposite and nano/Styrene. Mechanical and biological tests samples according toASTM-D143 and EN113 respectively were treated by vacuum- pressure method using cylinder experimental. The mechanical tests were considered for each level 5 repeat and for biological test for each level 10 repeat. The presence of zinc oxide nanoparticles on cell wall and styrene in the cell cavities were confirmed by Scanning electron microscopy. According to the results, bending strength, bending modulus, hardness and pressure parallel to grain for nano/styrene samples with highest improvement were increased 36.74, 40.23, 60.58 and 25.07 in comparison with control respectively. Also, decay resistance of treated samples increased, so that maximum and least weight loss were recorded for control and nano/styrene samples with 25.81 and 3.37% weight loss.
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
