Your search resulted in 21 documents.
Lignin blocking effects on weathering process of wood plastic composites
2010 - IRG/WP 10-40529
The weathering of wood–plastic composites (WPC) causes discoloration which affects their aesthetic aspects. It has been proved that these discolorations are due to lignin degradation. Effects of blocking the susceptible structure of lignin assessed by chemical treatment such as acetylation and methylation are reported in this study. Surface chemical change of wood plastic composite (WPC) formula...
P Darabi, A Naghi karimi, S Ahmade Mirshokraie, M-F Thévenon
Investigation of temperature effect on fixation of Celcure preservative (ACC) in beech (Fagus orientalis)
2001 - IRG/WP 01-40200
In this research, the fixation speed of Celcure 2% (ACC) preservative salt, under temperature of 17°C, 27°C and 50°C, on intact and stained wood specimens of beech was investigated. For this purpose, blocks of wood with 5x5x7 cm dimensions were prepared and saturated with 2% ACC concentration by full-cell process. The specimens were put in three incubators at the above-mentioned temperatures. F...
A Karimi, M Ghorbani
Investigation of temperature effect on fixation of Celcure preservative (ACC) in Hornbeam (Carpinus betulus I)
2003 - IRG/WP 03-30304
In this research, the fixation speed of Celcure 2 % (ACC) preservative salt, under temperature of 30 ºC, 40 ºC and 50 ºC on intact wood specimens of hornbeam was investigated. For this purpose, blocks of wood with 2Í 2 Í2 cm dimensions of hornbeam were prepared and saturated with 2% ACC concentration by full-cell process. The specimens were put in three incubators at the above-mentioned temperatures. For measuring the percentage of fixation through time, the specimens were extracted by using hydraulic pressure equipment, under 70 Mpa pressure. The PH of extraction was measured with the method of Diphenyl Carbazid and by using spectrophotometer. This measurement was done continuously and the amount of 6-valence chromium concentration present in the extract was compared with the amount of chromium concentration in the primary solution and then the percentage of fixation was calculated.
The results showed that the decrease in 6-valence chromium is accompanied with increase of PH, this due to absorption of positive hydrogen ion by 6-valence chromium for reduction to 3-valence chromium and also ion –exchange of active components with wood during the primary phase of fixation. Also, the time necessary for reaching complete fixation in intact wood in the fixation temperature conditions of 30, 40, 50 ºC were 98, 52, 24 hours, respectively. In general, the results showed that temperature has effective role accelerating of fixation process.
R Imani, R E Majdar, A Karimi
Influence of Acetylation on Fire Resistance of Beech Plywood
2006 - IRG/WP 06-40326
Influence of acetylation on fire resistance was studied in beech plywood. Beech layers were acetylated in a reactor with acetic anhydride at 120ºC for varying durations. Plywoods were made from the acetylated layers and directly exposed to burning flame from their edges for 60s according to ISO 11925-3. Ignition and glowing time were measured in samples. Results were analyzed statistically based ...
B Mohebby, A Talaii, A Karimi , S Kazemi Najafi
Effect of fiber type and content on the natural durability of wood flour/high density polyethylene composites against rainbow fungus (Coriolus versicolor)
2007 - IRG/WP 07-40387
In order to evaluate the effect of fiber type and content on the natural durability of wood flour/high density polyethylene (HDPE) composites against Coriolus versicolor, samples containing 25% and 50% by weight of various natural fibers and HDPE were selected. Natural fibers included in the study were wood flour, rice hulls, hemp fibers and newsprint. Samples containing 25% and 50% natural fiber ...
A Karimi, M Tajvidi, S Pourabbasi
Effect of Compatibilizer on the Natural Durability of Wood Flour/High Density Polyethylene Composites Against Rainbow Fungus (Coriolus versicolor)
2007 - IRG/WP 07-40388
To evaluate the effect of compatibilizer on the natural durability of wood flour/high density polyethylene composites against Coriolus versicolor, composites containing 25% and 50% by weight maple wood flour and 1% and 2% compatibilizer (Maleic anhydride polyethylene (MAPE)), respectively, were sampled. Identical specimens of the same composites without the compatibilizer were also prepared. ...
Sara Pourabbasi, A Karimi, D Parsapajouh, M Tajvidi, M Soleymani
Biological resistance of acetylated particleboards exposed to white (Trametes versicolor (and brown (Coniophora puteana) rot fungi
2010 - IRG/WP 10-40534
This research was conducted to investigate the effect of acetylation on bioresistance of particleboard produced from acetylated wood chips of Fagus orientalis exposed to white (Trametes versicolor (and brown (Coniophora puteana) rot fungi. After 12 hours soaking in acetic anhydride, in order to achieve three level of weight gains, 5, 9 and 16%, acetylated particles were heated in an oven at 120 c...
M Ghorbani kokandeh, K Doosthoseini, A N Karimi, B Mohebby, H Asghari
Comparative Study of Heat Treatment of Beech Wood in Hot Water and Steam Medium
2010 - IRG/WP 10-40536
Heat treatment of wood is an effective method to improve the dimensional stability and durability against biodegradation. Heat treatments of beech wood in 2 different mediums (hot water and steam) in 180ºC were compared in physical, mechanical and anatomical properties. Mass loss in hydrothermally treated wood was higher than hygrothermally treated samples. Mechanical properties (MOR, MOE and CS)...
A Talaei, K Yaghoobi, A N Karimi
Effects of Heat-Treatment in Hot Water and Steam Mediums on Gas Permeability of Beech Wood
2011 - IRG/WP 11-40557
Heat-treatment, as a major method of wood modification, improving dimensional stability, and natural durability, has been studied greatly from different aspects. The effect of heat-treatment on gas permeability, as an important physical property of wood, in two different mediums of hot water and steam, as well as in two buffers of 7 and 8, is the main topic of the present study. Hydrothermal treat...
H Reza Taghiyari, A Talaei, A Karimi
Effects of nano-silver on brittleness of heat-treated solid woods
2011 - IRG/WP 11-40572
The present study is aimed at the effect of heat-treatment of normal as well as nano-silver-impregnated Populus nigra, Populus deltoides, and Fagus orientalis on brittleness. Specimens were impregnated with 200 ppm water-based solution of nano-silver particles under 3 bars in a pressure vessel using empty-cell process. For heat treatment, both nano-silver-impregnated and normal specimens were kept...
H Reza Taghiyari, B Moradi Malek, A Karimi
Effects of Nano-Wollastonite on Ignition Time Reduction in MDF
2012 - IRG/WP 12-40576
Effects of wollastonite nano-fibers on ignition time reduction in medium density fiberboard were studied. Nanowollastonite was applied at 5, 10, 15, and 20 g/kg dry weight basis of wood fibers and compared with control specimens. Two application methods of nanowollastonite were used: surface application, and internal application. Specimens of 150×130×9 mm were prepared and the ignition times wer...
H Reza Taghiyari, H Rangavar, P Noori, A Karimi
Effects of Nano-Zycosil on Liquid and Gas Permeability of MDF
2012 - IRG/WP 12-40578
Effects were studied of zycosil nanoparticles, with size range from 30 to 90 nm, on liquid and gas permeability of medium density fiberboard. 100 g of nanozycosil was added to each kg of dry fibers. Density was kept constant at 0.67 g/cm3. The obtained results indicated that addition of zycosil to the mat resulted in a significant increase in gas permeability due to the lower fiber-content in the ...
H Reza Taghiyari, K Heidarhaee, P Noori, A Karimi
Study on the Effect of Combined Nanosilver-Hygrothermal Treatment on Wood Properties
2012 - IRG/WP 12-40581
In this study, the impregnation process with nanosilver solution, before hygrothermal treatment was carried out to investigate its effect on some physical and mechanical properties of Iranian beech (Fagus orientalis Lipsky) and Russian imported spruce (Picea abies). Wood specimens were impregnated with nanosilver solution (400ppm) in an impregnation tank under pressure of 0.25 Mpa, for 20 minutes....
G Rassam, H Reza Taghiyari, A Karimi, B Jamnani, M Ebrahimi
Effects of nano-wollastonite impregnation on fire resistance and dimensional stability of Poplar wood
2012 - IRG/WP 12-40595
The fire-retardant properties of Nano-Wollastonite (NW) in poplar wood (Populus nigra) were determined in this study. Some physical properties such as water absorption, volumetric swelling and Anti-Swelling Efficiency (ASE) were also measured. Specimens were prepared according to the ISO 11925 standard for the fire-retarding properties, and ASTM D4446-2002 standard for the physical properties. Imp...
A Karimi, A Haghighi Poshtir, H Reza Taghiyari, Y Hamzeh, A Akbar Enayati
Mechanical Properties of Hydrothermally Treated Beech Wood in Buffered Mediums
2012 - IRG/WP 12-40597
Hydrothermal treatment of beech wood in buffered mediums was carried out by aim of controlling the destructive effect of acids formed by degradation of carbohydrates on strength properties. Different mediums (water, buffer5, 7 and 8) and temperatures (160 and 180 °C) were used. Mechanical properties of specimens including modulus of rupture (MOR), modulus of elasticity (MOE) and toughness were de...
A Talaei A Karimi, K Yaghoobi, A Talaei
Chemical Analysis of Hydrothermally Treated Beech Wood in Buffered Mediums
2012 - IRG/WP 12-40604
Hydrothermal treatment of beech wood in buffered mediums was carried out to study the effect of different mediums of heat treatment on crystallinity index of treated specimens due to degradation of carbohydrates. Different mediums (water, buffer5, 7 and 8) and temperatures (160 and 180 °C) were used. ATR spectra focusing on indexes of carbohydrates degradation obtained and analyzed. Results showe...
A Talaei, A Karimi
Study on the Effect of Combined Nanosilver-Hygrothermal Treatment on Wood Properties
2012 - IRG/WP 12-40581
In this study, the impregnation process with nanosilver solution, before hygrothermal treatment was carried out to investigate its effect on some physical and mechanical properties of Iranian beech (Fagus orientalis Lipsky) and imported Russian spruce (Picea abies). Wood specimens were impregnated with nanosilver solution (400ppm) in an impregnation tank under pressure of 0.25 Mpa, for 20 minutes....
G Rassam, H Reza Taghiyari, A Karimi, B Jamnani, M Ebrahimi
Influence of Heat Treatment Medium on Fungal Resistance of Beech Wood
2013 - IRG/WP 13-40643
Hydrothermal treatment of beech wood (Fagus orientalis) performed in acidic, neutral and alkaline buffered mediums in 160 and 180°C. White rot fungi (Coriolus versicolor) and brown rot fungi (Coniophora puteana) were used to determine the influence of heat treatment mediums on the behaviour of fungal resistance. White rot of wood digest lignin rather than cellulose; while brown rot digests the ce...
A Talaei, A Karimi, M-F Thévenon
Nano-Zycosil in MDF. Part I: Gas and Liquid Permeability
2014 - IRG/WP 14-40652
Effects were studied of zycosil nanoparticles, with size range from 20 to 80 nm, on liquid and gas permeability of medium density fiberboard. Nanozycosil was used at four consumption levels of 0, 50, 100, and 150 g/kg dry wood fibers. Density of all treatments was kept constant at 0.67 g/cm3. The obtained results indicated that the addition of zycosil to the mat resulted in a significant increase...
H Reza Taghiyari, A Karimi, P M D Tahir, O Schmidt, E Bari, P Nouri , A Jahangiri
Effect of silver nanoparticles on the rate of heat transfer to the core of the medium-density fiberboard mat
2014 - IRG/WP 14-40653
Effect of silver nanoparticles on the rate of heat transferred to the core section of medium-density fiberboard (MDF) mat was studied here. A 400 ppm aqueous nanosilver suspension was used at three consumption levels of 100, 150, and 200 mL/kg based on the weight of dry wood fibers; the results were then compared with the control MDF panels. The size range of silver nanoparticles was 30-80 nm. Res...
H Reza Taghiyari, O Schmidt, E Bari, P M Tahir, A Karimi, P Nouri, A Jahangiri
Effect of Nano-Wollastonite on Water Absorption in Particleboard
2014 - IRG/WP 14-40662
Effects of wollastonite nanofibers on physical properties of particleboard were studied. Nano-wollastonite (NW) was applied at 5, 10, 15, and 20 g/kg, based on the dry weight of wood-chips, and compared with control specimens. Two application methods of NW were used: surface application (SA), and internal application (IA). Density was kept constant at 0.68 g/cm3 for all treatments. Tests were carr...
S Karimi, H Reza Taghiyari, A Karimi, P M Tahir, J Abdul Halip