Management and Economics wood
Neda Esmaeili; Maryam Ghorbani; Porya Biparva
Abstract
In this study, the mechanical and biological properties of modified poplar wood with glutaraldehyde and paraffin were investigated. Modification was performed with glutaraldehyde at different concentrations of glutaraldehyde, 5, 10 and 20% using magnesium chloride as a catalyst and then subsequently ...
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In this study, the mechanical and biological properties of modified poplar wood with glutaraldehyde and paraffin were investigated. Modification was performed with glutaraldehyde at different concentrations of glutaraldehyde, 5, 10 and 20% using magnesium chloride as a catalyst and then subsequently with paraffin by vacuum-pressure method. Increasing concentration of glutaraldehyde caused to weight gain and bulking wood cell wall, subsequently reduced paraffin penetration into the porous structure of wood. Biological resistance exposed to white rot fungi and mechanical properties were measured according to the standards EN113 and ASTM D143-94, respectively. Scanning electron microscopic images showed bulking of cell walls and paraffin presence in cell cavities. According to results of TGA, increasing of modification intensity decreased mass loss due to cross linking formation between glutaraldehyde and cell wall polymers. Paraffin at combined modification containing 10% and 20% glutaraldehyde improved significantly the modulus of elasticity. Glutaraldehyde reduced bending strength, but paraffin present in the modified samples improved it. The Glutaraldehyde increased compression strength parallel to grain and hardness that the improvement was more obvious in combined modification. Modification with glutaraldehyde enhanced decay resistance exposed to white rot fungi, and this improvement intensified at the presence of paraffin. Inhibitory influence of chemical modification on wood attacking white rot fungi can be attributed to decreases the wood moisture, bulking of cell walls and blocking cell cavities.
Management and Economics wood
Neda Esmaeeli; Maryam Ghorbani; pourya biparva
Abstract
This research was conducted to determine the optimal conditions for chemical modification of poplar wood with glutaraldehyde and its effect on the physical properties of products. Test samples were prepared according to the standard ASTM-D1037 and impregnated in the laboratory cylinders with Glutaraldehyde ...
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This research was conducted to determine the optimal conditions for chemical modification of poplar wood with glutaraldehyde and its effect on the physical properties of products. Test samples were prepared according to the standard ASTM-D1037 and impregnated in the laboratory cylinders with Glutaraldehyde at a concentration of 10% by using vacuum-pressure method. Modification reaction was done in two procedure. Heating first in the laboratory cylinder (Hydrothermal) for 4 hour and second in oven for 4 level 4,12,24,48 and 48hours. Weight percent gain of modified by hydrothermal and oven method was measured 2.10, 9.26, 10.02, 11.40 and 14.15% respectively. Chemical modification with glutaraldehyde by hydroxyl group's substitution, reduced the uptake of water and swelling of poplar wood. So that at the end of soaking in water the heating in the oven for 48 hours with minimum water absorption and dimensional changes in the 57.32 and 12.08 respectively, and highest bulking, ASE and ASE′ in 8.31,67 and 35.51% respectively was selected as the optimal level. This improvement compared to other modification levels demonstrates the forming of permanent Cross-linking of acetal that increased by Prolongation of the heating time.
