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Vol 15, No 2 (2013) by Hamid R Taghiyari

The effects of heat-treatment on permeability are the main topic of the present study. Longitudin... more The effects of heat-treatment on permeability are the main topic of the present study. Longitudinal dowel shape pairs of specimens were prepared from three native species and their specific gas permeability values were measured. From each pair, one specimen was kept for heat-treatment and the other was impregnated with 200 ppm nano-silver suspension; the size range of nanoparticles was 20-80 nm. In six consecutive steps, each pair was heated at 50, 75, 100, 125, 150, and 185°C. Results showed that gas permeability increased when specimens were heated at 50°C as a result of the loss of bond-water and consequent shrinkage. Permeability sharply decreased when the specimens were heated at 75°C and gradually increased at each step up-to 150°C. At 185°C, permeability again decreased in. The sharp decrease in permeability at 75°C was possibly due to irreversible hydrogen bonding in the course of water movements within the vessel perforations and pore system of cell walls. The gradual increase in permeability at higher temperatures, though, might be due to higher internal stresses that are released as micro-cracks develop, thus leading to a greater capability of fluidtransfer. Nano-silver impregnation intensified this process.

Vol 17, No 1 (2015) by Hamid R Taghiyari

Effects of nano-clay on weight loss of wood-plastic composites (WPC) by five fungi were studied. ... more Effects of nano-clay on weight loss of wood-plastic composites (WPC) by five fungi were studied. Nanoclay particles of 20 to 50 nm size were applied at 2, 4, and 6% WPC of 0,90 g/cm 3 density. The white-rot fungi Physisporinus vitreus, Pleurotus ostreatus and Trametes versicolor as well as the brown-rot species Antrodia vaillantii and Coniophora puteana were used. Mass loss tests were conducted according to the European standard. The highest (3.2%) and lowest (0,2%) mass losses were produced by T. versicolor and P. vitreus in the control and 6%-nanoclay treatments, respectively. Obviously the weight loss of WPC depends on the fungus species. Although weight losses were extremely low, nano-clay considerably inhibited the growth of wood-deteriorating fungi. Mass loss correlated with water absorption. Universidad del Bío -Bío Rangavar, H. 2005. Instructions for wood-cement composite-boards using hardwoods. Wood Technology and Equipment Journal 236-241. Saber, R.; Shakoori, Z.; Sarkar, S.; Tavoosidana, Gh.; Kharrazi, Sh.; Gill, P. 2013. Spectroscopic and microscopic analyses of rod-shaped gold nanoparticles interacting with single-stranded DNA oligonucleotides. IET Nanobiotechnology 7(2): 42-49. Schmidt, O. 2006. Wood and tree fungi. Biology, damage, protection, and use. Springer, Berlin, Heidelberg, New York: 334p. Stark, N.M. 1997. Effect of species and particle size on properties of wood-flour-filled polypropylene composites. In: Proceeding of functional fillers for thermoplastic and thermosets. December 8 -10, San Diego, California, USA. Taghiyari, H.R.; Farajpour Bibalan, O. 2013. Effect of copper nanoparticles on permeability, physical, and mechanical properties of particleboard. European Journal of Wood and Wood Products 71(1): 69-77. Taghiyari, H.R.; Mobini, K.; Sarvari Samadi, Y.; Doosti, Z.; Karimi, F.; Asghari, M.; Jahangiri, A.; Nouri, P. 2013. Effects of nano-wollastonite on thermal conductivity coefficient of medium-density fiberboard.

Papers by Hamid R Taghiyari

Scientific reports, Feb 20, 2024

Sepiolite is a silicate mineral that improves the fire properties in solid wood when mixed with a... more Sepiolite is a silicate mineral that improves the fire properties in solid wood when mixed with a waterbased coating. The present study was carried out to investigate and evaluate the effects of sepiolite addition to acrylic-latex paint on the pull-off adhesion strength, as an important characteristic of paints and finishes used in the modern furniture industry and historical furniture as well for preservation and restoration of heritage objects. Sepiolite was added at the rate of 10%, and brushed onto plain-sawn beech (Fagus orientalis L.) wood specimens, unimpregnated and impregnated with a 400 ppm silver nano-suspension, which were further thermally modified at 185 °C for 4 h. The results showed that thermal modification had a decreasing effect on the pull-off adhesion strength, primarily as a result of the thermal degradation of cell-wall polymers (mostly hemicelluloses). Still, a decreased wettability as a result of condensation and plasticization of lignin was also partially influential. Based on the obtained results,thermal modification was found to have a significant influence on pull-off adhesion strength. Sepiolite addition had a decreasing effectin all treatments, though the effect was not statistically significant in all treatments. The maximum and minimum decreases due to sepiolite addition were observed in the unimpregnated control (21%) and the thermally-modified NS-impregnated (4%) specimens. Other aspects of the sepiolite addition, and further studies that cover different types of paints and coatings, should be evaluated before coming to a final firm conclusion in this regard.

Journal of Nanomaterials & Molecular Nanotechnology, 2014

Nanotechnology in Wood and Wood-Composite Materials Wood is a natural, biodegradable, and renewab... more Nanotechnology in Wood and Wood-Composite Materials Wood is a natural, biodegradable, and renewable material that canbe used in many applications, including structural members, ornamental objects, aerospace technology, etc. Its low thermal and electrical conductivity coefficients have made it unique for specific purposes since the creation of humanity. However, some of its other features are quite bothering such as its deterioration by a variety of fungi and insects, its susceptibility to fire, as well as the dimensional instability to water absorption. Over the past few decades, nanotechnology was utilized in many sciences and it was used to improve the quality of many materials, including wood and wood-composites.

Polymers, Sep 20, 2019

The aim of this study was to investigate the physical and mechanical properties of thermally modi... more The aim of this study was to investigate the physical and mechanical properties of thermally modified beech wood impregnated with silver nano-suspension and to examine their relationship with the crystallinity of cellulose. Specimens were impregnated with a 400 ppm nanosilver suspension (NS); at least, 90% of silver nano-particles ranged between 20 and 100 nano-meters. Heat treatment took place in a laboratory oven at three temperatures, namely 145, 165, and 185 • C. Physical properties and mechanical properties of treated wood demonstrated statistically insignificant fluctuations at low temperatures compared to control specimens. On the other hand, an increase of temperature to 185 • C had a significant effect on all properties. Physical properties (volumetric swelling and water absorption) and mechanical properties (MOR and MOE) of treated wood demonstrated statistically insignificant fluctuations at low temperatures compared to control specimens. This degradation ultimately resulted in significant decrease in MOR, impact strength, and physical properties. However, thermal modification at 185 • C did not seem to cause significant fluctuations in MOE and compression strength parallel to grain. As a consequence of the thermal modification, part of amorphous cellulose was changed to crystalline cellulose. At low temperatures an increased crystallinity caused some of the properties to be improved. Crystallinity also demonstrated a decrease in NS-HT185 in comparison to HT185 treatment. TCr indices in specimens thermally treated at 145 • C revealed a significant increase as a result of impregnation with nanosilver suspension. This improvement in TCr index resulted in a noticeable increase in MOR and MOE values. Other properties did not show significant fluctuations, suggesting that the effect of the increased crystallinity and cross-linking in lignin was more than the negative effect of the low cell-wall polymer degradation caused by thermal modification. Change of amorphous cellulose to crystalline cellulose, as well as cross-linking in lignin, partially ameliorated the negative effects of thermal degradation at higher temperatures and therefore, compression parallel to grain and modulus of elasticity did not decrease significantly. Overall, it can be concluded that increased crystallinity and cross-linking in lignin can compensate for some decreased properties caused by thermal modification, but it would be significantly dependent on the temperature under which modification is carried out. Impregnating specimens with silver nano-suspension prior to thermal modification enhanced the effects of thermal modification as a result of improved thermal conductivity.

International Journal of Environmental Science and Technology, Dec 15, 2015

Improving effects of recycled polyethylene on dimensional stability, mechanical properties, and r... more Improving effects of recycled polyethylene on dimensional stability, mechanical properties, and reduction in adhesive consumption of particleboard made from canola residues were studied here. Canola residues were consumed at 0, 30, and 50 % consumption levels, based on the dry weight of wood particles. Recycled low-density polyethylene was also consumed at two levels of 20 and 30 %. Urea-formaldehyde resin was used for all treatments at three levels (6, 8, and 10 %). Results showed that polyethylene had significant improving effects on all the physical and mechanical properties. Increase in canola content, however, increased modulus of rupture and modulus of elasticity due to the more slenderness ratio of canola residue, but it decreased the internal bond and physical properties because of the higher specific surface area of canola particles. Properties of the panels made from 30 % canola residues, 30 % polyethylene, and 8 % ureaformaldehyde resin were in compliance with the EN 312-2 standards. It can be concluded that the improving effects of recycled polyethylene can compensate for part of the ureaformaldehyde resin, and therefore, lower urea-formaldehyde content can be used, lowering the production costs due to high-value urea-formaldehyde resin. At the same time, the potentiality of formaldehyde emission into the atmosphere would also be decreased.

European Journal of Wood and Wood Products, Jun 5, 2013

Effects of silver nanoparticles and fungal degradation on the weight loss and chemical compositio... more Effects of silver nanoparticles and fungal degradation on the weight loss and chemical composition of heat-treated poplar wood were studied. Wood blocks were impregnated with a 400 ppm nanosilver suspension under 3 bar pressure for 20 min using Lowry process (edited empty cell). Heat-treatment was carried out at 135, 160 and 185 °C. Specimens were divided into 4 groups; control, nanosilver impregnated, heat-treated and impregnated-heat treated specimens (135, 160 and 185 °C). All samples from the internal and superficial parts of the blocks were exposed to the white rot fungus Trametes versicolor. The results of heat-treated samples indicated higher amount of Klason lignin and extractives, but lower holocellulose and cellulose content. Furthermore, heat-treatment illustrated an increasing effect on the fungal resistance. For all the properties, significant difference was found between the internal and superficial test specimens. Nanosilver impregnation had an intensifying effect on the results of the heat-treatment. Impra ¨gnierung mit Silber-Nanopartikeln auf den pilzbedingten Holzabbau, die Dichte und die chemische Zusammensetzung von thermisch behandeltem Pappelholz (Populous euroamerica) Zusammenfassung Untersucht wurde der Einfluss einer Impra ¨gnierung mit Silber-Nanopartikeln auf den pilzbedingten Holzabbau, den Masseverlust und die chemische Zusammensetzung von thermisch behandeltem Pappelholz. Holzpru ¨fko ¨rper wurden mit einer 400 ppm Nanosilber-Lo ¨sung bei einem Druck von 3 bar und u ¨ber eine Dauer von 20 Minuten nach dem Lowry-Verfahren impra ¨gniert. Die Temperaturen der thermischen Behandlung betrugen 135, 160 und 185 °C. Die Pru ¨fko ¨rper wurden in die vier Gruppen Kontrolle, mit Nanosilber impra ¨gnierte, thermisch behandelte sowie impra ¨gnierte und thermisch behandelte Pru ¨fko ¨rper (135, 160 und 185 °C) unterteilt. Alle Proben aus dem inneren und dem oberfla ¨chennahen Bereich der Pru ¨fko ¨rper wurden dem Weißfa ¨ulepilz Trametes versicolor ausgesetzt. Die thermisch behandelten Pru ¨fko ¨rper wiesen eine ho ¨here Menge an Klason-Lignin und Extraktstoffen auf, jedoch einen geringeren Holocellulose-und Celluloseghalt. Daru ¨ber hinaus zeigte sich eine Zunahme der Pilzresistenz aufgrund thermischer Behandlung. Bei allen Versuchen ergaben sich signifikante Unterschiede zwischen den inneren und den oberfla ¨chennahen Proben. Die Nanosilber-Impra ¨gnierung wirkte sich positiv auf die Ergebnisse der thermischen Behandlung aus.

Special topics & reviews in porous media, 2013

Journal of Porous Media, 2016

Fibers

Unlike the recycling of particleboards, the recycling of medium-density fiberboards (MDF) is not ... more Unlike the recycling of particleboards, the recycling of medium-density fiberboards (MDF) is not a widespread industrial practice, and currently, most waste MDF panels are landfilled or incinerated after the end of their life cycle. Therefore, it is of great importance to develop cost-effective methods for MDF recycling. The extraction of resins used for bonding the panels, mostly urea–formaldehyde (UF) resins, is carried out mainly with hydrolysis. Hydrothermal hydrolysis is a more environmentally friendly and cheaper recycling technique compared to acid hydrolysis and allows obtaining a high yield of recycled fibers. The aim of this research work was to investigate and evaluate the effect of hydrolysis regime applied on its efficiency and on the properties of the recycled MDF fibers. For this purpose, thermal hydrolysis was carried out in an autoclave with saturated steam as a heat carrier. The main novelty of the research is the preliminary preparation of the recyclable MDF in sa...

Wood Material Science and Engineering, May 17, 2023

Wood and Fiber Science, Jan 23, 2019

Many wood species are resistant to penetration of liquids. Impermeability can affect a variety of... more Many wood species are resistant to penetration of liquids. Impermeability can affect a variety of properties including the ability to deliver preservatives, adhesive bonding, and coating applications. Developing methods for altering this characteristic could help in utilization of impermeable species. One method for altering wood characteristics is through the use of supercritical carbon dioxide (SC-CO 2 ) which can solubilize a wide range of organic compounds. In this report, we examined the ability of varying SC-CO 2 conditions to improve the permeability of Paulownia fortunei. All of the processes tested improved gas permeability and most reduced the frequency of tyloses in the vessels. The results suggest that SC-CO 2 could be used to modify the permeability of this species.

Fullerenes Nanotubes and Carbon Nanostructures, Nov 2, 2017

ABSTRACT Encapsulation of cellulose chain into carbon nanotubes and boron nitride nanotubes was i... more ABSTRACT Encapsulation of cellulose chain into carbon nanotubes and boron nitride nanotubes was investigated to find out the possibility of band gap engineering in these nanotubes. The structural stability and the electronic properties of the zigzag carbon nanotubes and boron nitride nanotubes filled with cellulose chain were studied using density functional theory. It was found that encapsulation of cellulose chain into nanotubes was an exothermic process. The metallic properties of the carbon nanotubes did not change by cellulose encapsulation. The semiconductor and insulator nanotubes filled with cellulose were shown semiconducting properties. The energy band gap of these tubes was decreased by cellulose encapsulation. The results demonstrated the ability of band gap engineering through the encapsulation of cellulose chain into carbon nanotubes and boron nitride nanotubes.

Springer eBooks, Dec 6, 2022

International Journal of Adhesion and Adhesives, 2021

Nano, 2017

Molecular dynamics simulations were performed to study helium adsorption on carbon and cellulose ... more Molecular dynamics simulations were performed to study helium adsorption on carbon and cellulose nanotubes. Adsorption isotherms were analyzed at different temperatures and pressures. All adsorption isotherms for carbon and cellulose nanotubes were predicted to be of Langmuir shape type I. Helium adsorption was observed both inside and outside of open-ended tubes. Increasing temperatures caused lower helium adsorption on carbon and cellulose nanotubes. The calculated quantities confirmed that the adsorption capacity of the cellulose nanotube was greater than that of the carbon nanotube. The adsorption capacity, isosteric heat of adsorption and binding energy indicated that cellulose nanotubes as well as carbon nanotubes are proper materials for gas storage.

Scientific reports, Feb 20, 2024

Journal of Nanomaterials & Molecular Nanotechnology, 2014

Polymers, Sep 20, 2019

International Journal of Environmental Science and Technology, Dec 15, 2015

European Journal of Wood and Wood Products, Jun 5, 2013

Special topics & reviews in porous media, 2013

Journal of Porous Media, 2016

Fibers

Wood Material Science and Engineering, May 17, 2023

Wood and Fiber Science, Jan 23, 2019

Fullerenes Nanotubes and Carbon Nanostructures, Nov 2, 2017

Springer eBooks, Dec 6, 2022

International Journal of Adhesion and Adhesives, 2021

Nano, 2017

DOAJ (DOAJ: Directory of Open Access Journals), May 1, 2014

In this research, the combined effect of impregnation of wood with nanosilver solution and hygrot... more In this research, the combined effect of impregnation of wood with nanosilver solution and hygrothermal treatment on some physical and mechanical properties of beech (Fagus orientalis Lipskey) and spruce (Piceaabies) woods was studied. Wood specimens, Initially, were impregnated in an impregnation cylinder for 20 minutes at the pressure of 0.25 MPa, with nanosilver solution. Then, hygrothermal treatment was carried out at the temperatures of 120, 150 and 180°C for 1, 3 and 5 hours. Control specimens, without any impregnation process, were hygrothermally treated. Volumetric Swelling after 2 and 24 hours soaking in water, bending strength, impact load resistance and compressive strength parallel to the grain of specimens were measured, according to ASTM D143 and all data were analyzed statistically. The results showed that swelling and mechanical properties were decreased by increasing the temperature and duration of hygrothermal treatment. Also, nanosilver impregnated specimens which were treated at 180 ˚C had lower swelling without Not clear and not seems. Consequently or it can be concluded that with nanosilver impregnation process of wood, hygrothermal treatment would be carried out at higher temperature (180 ˚C) to obtain better dimensional stability with no more decrease in mechanical properties.

In the present study, Fire – Retarding properties of nano-bentonite in medium density of fiberboa... more In the present study, Fire – Retarding properties of nano-bentonite in medium density of fiberboard (MDF) was studied. 10% of urea-formaldehyde resin was used as the adhesive of the matrix. Nano Bentonite at 5 levels (0%, 5%, 10%, 15% and 20%) g/kg based of dry weight of fibers was used with the consumption of Urea-Formuldehyde (UF). Press pressure of 150 bar and temperature of 170during 4, 5, and 6 minutes were applied. Density was kept constant at 0.7 g/cm3 in all treatments. The measured properties consisted of mass reduction, inflammation time, fire-endurance, melting time and the burnt area. The results revealed that Nano-Bentonite had significant effect in approving fire retarding properties in medium density fiber board. The best properties at the level of 10% obtained and the same level recommended for industry use. The use of Nano-Bentonite more than 10% decreased the stickiness and the partly surface of fiberboards.