Continuous-fiber reinforced WPCs were prepared using an extruder with a special die. The effects ... more Continuous-fiber reinforced WPCs were prepared using an extruder with a special die. The effects of the amount (1 to 7 bundles) and type of fiber (aramid rovings and yarns and carbon and glass yarns) on the mechanical properties of WPCs were studied. The adding of continuous fibers led the tensile, flexural and impact strength of the composites to increase by up to 47.3%, 83.1% and 713.4%, respectively. The damping ratio analysis revealed that the interfacial bonding of glass-yarn reinforced WPCs was the best among the tested samples. Adding continuous fibers to WPCs at a low volume fraction can promote their use as load-bearing engineered materials.
An ecofriendly approach was developed for preparing copper-doped carbon dots (CDs) with superior ... more An ecofriendly approach was developed for preparing copper-doped carbon dots (CDs) with superior photocatalysis using chromium-copper-arsenic (CCA)-treated wood waste as a precursor. Original wood (W-CDs), CCA-treated wood (C-CDs), and bioremediation CCA wood (Y-CDs) were used as the precursors. The chemical composition and structural, morphological, and optical properties, as well as the photocatalytic ability of the synthesized CDs varied with wood type. The C-CDs and W-CDs had similar characteristics: quasispherical in shape and with a diameter of 2 to 4.5 nm. However, the Y-CDs particles were irregular and stacked together, with a size of 1.5–3 nm. The presence of nitrogen prevented the formation of an aromatic structure for those CDs fabricated from bioremediation CCA wood. The three synthesized CDs showed a broad absorption peak at 260 nm and a weak absorption peak at 320 nm. Proof of the model study for the fabrication of luminescent CDs from CCA wood waste for bioimaging was...
This study evaluated the reinforcement potential of Posidonia oceanica fibres (POF) and deinking ... more This study evaluated the reinforcement potential of Posidonia oceanica fibres (POF) and deinking paper sludge (DPS) on the thermo-mechanical properties of high density polyethylene (HDPE) binary and hybrid composites. The weight ratios of the fillers (POF and/or DPS) to the polymer were 0:100; 20:80; 30:70 and 40:60 (wt:wt). Maleated polyethylene (MAPE) was added at a proportion of 3% by weight. The chemical composition, structural and thermal properties and morphology of the fillers were investigated by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The mechanical (tensile and impact strength) and thermal properties (TGA and Differential Scanning Calorimetry (DSC)) of the binary and hybrid composites were also investigated. Binary and hybrid composite properties depend on the chemical composition of the fillers (POF and DPS), the filler/matrix interfacial adhesion and the POF: DPS ratio. The tensile modulus and strength of the binary and hybrid composites increased with increasing filler content (POF or/and DPS). A better interfacial adhesion between fillers and matrix was achieved in the presence of MAPE. HDPE/POF/MAPE composites achieved the highest tensile modulus and strength with 40% POF. But lower thermal stability, ductility and impact strength were found with the addition of the POF. However, the thermal stability, crystallinity, ductility and toughness improved in HDPE/POF/DPS/MAPE hybrid composites due to the addition of DPS or the substitution of POF by DPS.
h i g h l i g h t s Review on bioremediation of treated wood. Conceptualization of bioremediation... more h i g h l i g h t s Review on bioremediation of treated wood. Conceptualization of bioremediation into direct and indirect microbial remediation. The combination of direct and indirect bioremediation is a promising decontamination approach. Alternatives and reuse of detoxified wood after bioremediation are detailed. Challenges and prospects of bioremediation of contaminated wood are discussed.
We investigated the effects of polymer blend variation on the physical, mechanical, and thermal p... more We investigated the effects of polymer blend variation on the physical, mechanical, and thermal properties of wood-polymer composites (WPC). We used high-density polyethylene (HDPE) and polypropylene (PP) and a combination of 80% PP, 20% HDPE, and 80% HDPE, 20% PP as polymer blends for WPC formulations to simulate recycled plastics. We used black spruce (Picea mariana Mill.) hammer milled fibers (75–250 μm) at 35 wt% as a filler for all the formulations. A two-step process was used for WPC manufacturing; pellet extrusion followed by test samples injection. Tensile and three bending tests characterized the WPC mechanical properties. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) characterized the WPCs’ thermal properties. Water absorption and contact angle measurements assessed the composite dimensional stability. Infrared spectroscopy (FTIR) and electron scanning microscopy (SEM) investigated the WPCs’ surface chemistry and microstructure. Mechanical pr...
This study aims to investigate the feasibility of producing OSB from softwood species used in the... more This study aims to investigate the feasibility of producing OSB from softwood species used in the Eastern Canadian softwood lumber industry in the context of the overcapacity of softwood chips traditionally produced for the pulp and paper industry. Balsam fir, black spruce, and jack pine logs were used to make 15 mm thick OSB panels with a target density of 600 kg/m3. The panels were manufactured at a temperature of 210 °C during a pressing cycle of 300 s. Strands with different thicknesses were used to obtain a constant specific surface of 6.7 m2/kg for the three species. The bending modulus of the rupture and modulus of elasticity, internal bond, and thickness swelling of the OSB panels were determined and compared to the CSA standard requirements. The species significantly affected the physical and mechanical properties of OSB. The bending properties of OSB decreased with an increase in the species wood density. The internal bond strength of OSB increased with the increase in spe...
To better understand the genetic control of growth and wood properties in the hybrid poplar (Popu... more To better understand the genetic control of growth and wood properties in the hybrid poplar (Populus spp.), genetic relationships of selected wood properties with growth traits were examined in a 3-yr-old clonal trial located in Windsor and St-Ours, southern Quebec, Canada. In total, 371 trees from 21 hybrid poplar clones were sampled at the two locations. Clone effects are stronger than growth traits effects on wood density and initial moisture content. The estimated clonal repeatability for wood density (0.92) and initial moisture content (0.80) across the two sites are thus considerably higher than for dbh (0.64) and tree height (0.72). Neither wood density nor mean fiber length were found to significantly correlate with growth traits. This suggests that in the hybrid poplar clones selection for growth traits will not result in a significant reduction in the wood quality traits. Selection for stem dry fiber weight appears to be an optimal selection strategy, as it will lead to the highest genetic gain in stem dry fiber yield, or maximum fiber production while wood density is improved. FOR. SCI. 49(6):00-00.
Estimations of transition age (TA) and juvenile wood proportion (JWP) are important for wood indu... more Estimations of transition age (TA) and juvenile wood proportion (JWP) are important for wood industries due to their impact on end-product quality. However, the relationships between analytical determination of TA based on tracheid length (TL) and recognized thresholds for adequate end products have not yet been established. In this study, we used three different statistical models to estimate TA in white spruce (Picea glauca (Moench) Voss) based on TL radial variation. We compared the results with technological maturity. A two-millimeter threshold, previously suggested for good paper tear strength, was used. Tracheid length increased from pith to bark and from breast height to upper height. Juvenile wood (JW) was conical with the three models. At breast height, TA ranged from 11 to 27 years and JWP ranged from 15.3% to 47.5% across the three models. The linear mixed
Flavia Lega Braghiroli, Research Forest Institute (RFI), University of Québec in Abitibi-Témiscam... more Flavia Lega Braghiroli, Research Forest Institute (RFI), University of Québec in Abitibi-Témiscamingue (UQAT), 445 Boul. de l’Université, Rouyn-Noranda, Québec, QC J9X 5E4, Canada [email protected]; [email protected] Hassine Bouafif, Technology Center for Industrial Waste (CTRI), Cégep de l’Abitibi-Témiscamingue (College of Abitibi-Témiscamingue), 425 Boul. du Collège Rouyn-Noranda, QC J9X 5E5, Canada Carmen Mihaela Neculita, Research Institute on Mines and the Environment (RIME), University of Québec in Abitibi-Témiscamingue (UQAT), 445 Boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada Ahmed Koubaa, Research Forest Institute (RFI), University of Québec in Abitibi-Témiscamingue (UQAT), 445 Boul. de l’Université, Rouyn-Noranda, Québec, QC J9X 5E4, Canada
Abstract The project aims to develop cellulose in new biocomposites to produce dielectric materia... more Abstract The project aims to develop cellulose in new biocomposites to produce dielectric materials based on thermoplastic matrices. Cellulose fibers bring multiple advantages to thermoplastic matrices in mechanical, physicochemical, thermal, and dielectric properties. Although these biocomposites are known for their advanced mechanical properties, only a few studies investigated their dielectric behavior and the effect of cellulose fibers on these properties. The bio-based composites must have better dielectric properties and excellent ductility to use as insulators in electrical cables. Thus, we investigated the dielectric properties (dielectric constant (e’), loss factor (e’’), conductivity (σ) and resistivity (ρ)) of high-density polyethylene (HDPE) and cellulose fibers composites. Results prove that the addition of cellulosic fibers increased the dielectric constant, the loss factor, and the conductivity of the materials compared to the neat polymer. Composites with 50 wt% fiber content showed the highest values. Therefore, the volume resistivity of all the composites studied decreased with frequency and fiber content. In addition, the reinforced polymer exhibited an intermediate thermal behavior between the polymer and the fibers. Thus, they are thermally stable materials up to 320 °C.
In this study, activated biochar was produced using pilot-scale technologies of fast pyrolysis an... more In this study, activated biochar was produced using pilot-scale technologies of fast pyrolysis and activation to create desirable morphology, surface chemistry, and adsorptive properties for application in supercapacitors. First, residues from white birch were converted into biochar by fast pyrolysis (~ 450 °C). Then, physical (using CO2) or chemical (using KOH) activation was carried out in a homemade pilot-scale furnace at 900 °C. These synthesized materials presented distinct porosity structures: micro-/mesoporous (CO2 material) and highly microporous (KOH material), reaching surface areas of up to 1700 m 2 g-1. Electrochemical results showed that KOH-activated biochar had higher specific electrical capacitance in both acidic and neutral electrolytes with a maximum specific capacitance value of 350 and 118 F g-1 at 1 A g-1 , respectively; while, for CO2activated biochar, the maximum obtained values were 204 and 14 F g-1. The greater proportion of oxygenated and nitrogenated functional groups on the surface of the KOH activated biochar, along with its high surface area (with wider porosity), improved its performance as a supercapacitor electrode. Specifically, the low proportion of ultramicropores was determinant for its better electrochemical behavior, especially in the neutral electrolyte. Indeed, these results are similar to those found in the literature on the electrical capacitance of carbonaceous materials synthesized in a small-scale furnace. Thus, the chemical-activated biochar made from wood residues in pilot-scale furnaces is a promising material for use as electrodes for supercapacitors.
Continuous-fiber reinforced WPCs were prepared using an extruder with a special die. The effects ... more Continuous-fiber reinforced WPCs were prepared using an extruder with a special die. The effects of the amount (1 to 7 bundles) and type of fiber (aramid rovings and yarns and carbon and glass yarns) on the mechanical properties of WPCs were studied. The adding of continuous fibers led the tensile, flexural and impact strength of the composites to increase by up to 47.3%, 83.1% and 713.4%, respectively. The damping ratio analysis revealed that the interfacial bonding of glass-yarn reinforced WPCs was the best among the tested samples. Adding continuous fibers to WPCs at a low volume fraction can promote their use as load-bearing engineered materials.
Herein, Ti 3 C 2 T x (MXene) was synthesized and mixed with polyvinyl alcohol (PVA) to fabricate ... more Herein, Ti 3 C 2 T x (MXene) was synthesized and mixed with polyvinyl alcohol (PVA) to fabricate PVA/MXene nanocomposites. The results confirmed that delaminated MXene was successfully synthesized. The nanocomposites were obtained via casting/evaporation method. The thermal stability was evaluated by thermogravimetric analysis (TGA). For the PVA composites with content of 2 wt% MXene (PVA-MXene2), the thermal decomposition was retarded by approximately 20 C when the temperature was lower than 350 C compared with that of pure PVA. Moreover, the evolved gas products of the PVA/MXene composite were lower than those of pure PVA. For the first time, the flame retardancy of PVA/MXene nanocomposite was investigated using a microscale combustion calorimeter. The peak heat release rate (PHRR) and total heat release of the PVA composite were reduced by 25.7% and 25.5%, respectively, with 1 wt% of MXene. The temperatures at PHRR of PVA/MXene composites were improved with the addition of MXene. Moreover, the addition of MXene resulted in PVA composites with a higher tensile strength and elongation at break than those of a pure PVA film. The improvements in the flame retardancy, thermal and mechanical properties of PVA/MXene composites should enable a wide range of potential applications of MXenes in polymer matrices.
SO2, one of the most harmful gases, is generated when oxygen in air combines with sulfur species ... more SO2, one of the most harmful gases, is generated when oxygen in air combines with sulfur species from anthropogenic sources (e.g., the smelting of mineral ores). Thus, the objectives of this study are to assess the potential use of activated biochar for the removal of SO2, and to compare the impact of the activation process on the development of porosity and surface chemistry for SO2 adsorption. Results show that activated biochars develop porosity (with narrow and wide pores) and functional groups connected to their surface, which makes these materials suitable for adsorption of SO2. However, no linear relationship between textural properties and the amount of SO2 adsorbed by activated biochars from dynamic adsorption tests were noticed. In addition, the highest SO2 adsorption capacity was not reached for materials with the highest surface area, or micropore or ultramicropore volume. Specifically, steam-activated biochar had the best performance for the removal of SO2 due to its optimal surface area (590 m 2 g-1); volume of ultra-(0.22 cm 3 g-1), micro-(0.23 cm 3 g-1), and mesopores (0.11 cm 3 g-1); its basic character (not from nitrogenated groups); and the low percentage of acid-oxygenated functional groups connected to its surface. After six thermal regeneration cycles, activated biochar exhibited high SO2 removal capacity and high regenerability. Based on these findings, activated biochar made from forest wood residues has promising potential for the removal of gas contaminants.
Fifteen stems of jack pine (Pinus banksiana Lamb.) coming from three commercial thinned (CT) plot... more Fifteen stems of jack pine (Pinus banksiana Lamb.) coming from three commercial thinned (CT) plots (control, moderate, and intensive thinning) in the Abitibi-Témiscamingue region, Canada, were cross-cut into three 2.4 m length sections: bottom, middle, and top logs. Logs were processed with a chipper-canter at three cutting widths (CW 12.7, 19.1, and 25.4 mm), producing chips and a three faced cant. Chips were assessed by thickness, width, and length. Knot characteristics [total knot number (TKN) and area (TKA)] were assessed in the three cant faces. Growth ring attributes [earlywood density, latewood density (LWD), ring density (RD), earlywood proportion (EWP), ring width, and rings per mm], mechanical properties (shear, splitting, modulus of elasticity and modulus of rupture in bending), and basic density were evaluated on samples obtained within each CW area. The weighted mean chip thickness (WCT) was significantly affected by the log position in the stem (LPS) and CW. WCT increased as CW increased. Jack pine produce thicker chips than black spruce, when processed under the same cutting parameters. Thickness of chips coming from bottom and middle logs was similar due to a greater taper of the bottom log, which slightly increased this dimension. Thickest chips were produced in the top log due to a higher TKA and TKN towards the top of the stem. Multiple linear regressions showed that TKA, CW, and RD were significant predictors of WCT. Chip size distributions were significantly affected by the CT, LPS, and CW. Thinned stands logs appeared to produce smaller chips than natural stand logs. Moreover, chip thickness distribution was affected primarily by TKA and EWP, while the width and length distribution was mainly affected by EWP, LWD, and TKN. Chip size in jack pine is to some degree determined by knot attributes, growth ring characteristics, and wood density of the raw material. These results suggest the potential advantage of sorting logs prior to chipping, either by species, LPS and/or provenance (thinned or natural stands).
Abstract The aim of this study was to improve performance of a vegetable oil-based coating with a... more Abstract The aim of this study was to improve performance of a vegetable oil-based coating with addition of nanoparticles. Uniform distribution of added nanoclay, nanosilica and nanoalumina is the key to ensure the increased abrasion resistance. A high speed mixer, bead mill and ultrasonic mixer were used to disperse the nanoparticles into coatings. The quality of nanoparticle dispersion in liquid coating was studied by dynamic light scattering (DLS), and in dry film by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Using a high-speed mixer with addition of glass beads resulted in exceptional dispersion of nanoparticles in coating as confirmed by the above techniques. Although, addition of nanoclay had a positive effect on drying time of coating (reducing it by 37%), it had negative effects on viscosity (increasing it by 5 times). Overall, addition of 1% nanoparticles significantly increased the abrasion resistance of modified coating after 2000 abrasion cycles in comparison with pure unmodified coatings as applied on larch wood flooring samples.
Chromated copper arsenate-treated (cca) wood disposal faces environmental restrictions due to its... more Chromated copper arsenate-treated (cca) wood disposal faces environmental restrictions due to its toxicity, heavy metal leaching in storage sites, and greenhouse gas emissions during incineration. Thus, finding new management methods for this contaminated wood at the end of life is crucial. This study evaluated the effect of pyrolysis temperature (300, 400, and 500 °C), particle size, biochar yield, and the behavior of arsenic (As), chromium (Cr), and copper (Cu) during treated-wood pyrolysis. The highest biochar yield was obtained at 300 °C for fine particles. The biochar retention of heavy metals decreased with increasing pyrolysis temperature. At 300 °C, the highest biochar As, Cr, and Cu retentions were 76, 91, and 83%. At 500 °C, biochar only retained 43% of the As. Additionally, heavy metal leaching from the biochar exceeded the Environmental Protection Agency’s (EPA) maximum concentration limit of 5 mg/L. High-density polyethylene encapsulation of contaminated biochar reduced...
The flame retardancy of wood–polymer composites significantly affects their potential application... more The flame retardancy of wood–polymer composites significantly affects their potential applications. Thus, multilayered wood flour/high-density polyethylene (HDPE)/polycarbonate (PC) composites were prepared via thermocompression to improve the fire retardancy of wood–polymer composites in this paper. Thermal degradation behavior, flame retardancy, and flexural strengths of the resulting composites were investigated using a thermogravimetric analysis, cone calorimetry, and mechanical testing machine, respectively. Results revealed that the boric acid treatment reduced the heat release rate and total heat release of the wood flour/HDPE composites and increased their mass of residues. However, boric acid reduced the flexural strength of the resulting composites. The combustion test indicated that PC cap layers suppressed the combustion of the resulting composites via the formation of carbon layers. Adding PC layers reduced heat release and increased the flexural strength of the resulti...
Biochar is a carbon-rich organic material that has advantageous physicochemical properties for ap... more Biochar is a carbon-rich organic material that has advantageous physicochemical properties for applications in multidisciplinary areas of science and engineering, including soil amendment, carbon sequestration, bioenergy production, and site rehabilitation. However, the typically low porosity and surface area of biochars (from 0.1 to 500 m 2 g-1) limits the suitability for other applications, such as catalysis, electrochemistry, energy storage, and contaminant sorption in drinking water and wastewater. Given the high global demand for activated carbon products, scientists and industrialists are exploring the potential of biochar-derived biomass as precursors for activated carbons. This review presents and discusses the available studies on activated biochars produced from various precursor feedstocks and under different operating conditions in a two-step procedure: pyro-gasification (torrefaction, slow to flash pyrolysis, and gasification) followed by activation (physical, chemical or physicochemical). Findings from several case studies demonstrate that lignocellulosic residues provide attractive precursors, and that chemical activation of the derived biochars at high temperature and long residence time produces highly porous end materials. Indeed, the porosity of activated biochars varies greatly (from 200 to 2500 m 2 g-1), depending on the pyro-gasification operating conditions and the feedstock (different feedstocks have distinct morphological and chemical structures). The results also indicate that the development of highly porous activated biochars for diverse purposes (e.g., electrodes for electrochemical energy storage devices, catalyst supports and adsorbents for water treatment) would benefit both the bioeconomy and the environment. Notably, it would leverage the potential of added-value biomass as an economical, non-fossil, readily available, and renewable energy source.
Continuous-fiber reinforced WPCs were prepared using an extruder with a special die. The effects ... more Continuous-fiber reinforced WPCs were prepared using an extruder with a special die. The effects of the amount (1 to 7 bundles) and type of fiber (aramid rovings and yarns and carbon and glass yarns) on the mechanical properties of WPCs were studied. The adding of continuous fibers led the tensile, flexural and impact strength of the composites to increase by up to 47.3%, 83.1% and 713.4%, respectively. The damping ratio analysis revealed that the interfacial bonding of glass-yarn reinforced WPCs was the best among the tested samples. Adding continuous fibers to WPCs at a low volume fraction can promote their use as load-bearing engineered materials.
An ecofriendly approach was developed for preparing copper-doped carbon dots (CDs) with superior ... more An ecofriendly approach was developed for preparing copper-doped carbon dots (CDs) with superior photocatalysis using chromium-copper-arsenic (CCA)-treated wood waste as a precursor. Original wood (W-CDs), CCA-treated wood (C-CDs), and bioremediation CCA wood (Y-CDs) were used as the precursors. The chemical composition and structural, morphological, and optical properties, as well as the photocatalytic ability of the synthesized CDs varied with wood type. The C-CDs and W-CDs had similar characteristics: quasispherical in shape and with a diameter of 2 to 4.5 nm. However, the Y-CDs particles were irregular and stacked together, with a size of 1.5–3 nm. The presence of nitrogen prevented the formation of an aromatic structure for those CDs fabricated from bioremediation CCA wood. The three synthesized CDs showed a broad absorption peak at 260 nm and a weak absorption peak at 320 nm. Proof of the model study for the fabrication of luminescent CDs from CCA wood waste for bioimaging was...
This study evaluated the reinforcement potential of Posidonia oceanica fibres (POF) and deinking ... more This study evaluated the reinforcement potential of Posidonia oceanica fibres (POF) and deinking paper sludge (DPS) on the thermo-mechanical properties of high density polyethylene (HDPE) binary and hybrid composites. The weight ratios of the fillers (POF and/or DPS) to the polymer were 0:100; 20:80; 30:70 and 40:60 (wt:wt). Maleated polyethylene (MAPE) was added at a proportion of 3% by weight. The chemical composition, structural and thermal properties and morphology of the fillers were investigated by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The mechanical (tensile and impact strength) and thermal properties (TGA and Differential Scanning Calorimetry (DSC)) of the binary and hybrid composites were also investigated. Binary and hybrid composite properties depend on the chemical composition of the fillers (POF and DPS), the filler/matrix interfacial adhesion and the POF: DPS ratio. The tensile modulus and strength of the binary and hybrid composites increased with increasing filler content (POF or/and DPS). A better interfacial adhesion between fillers and matrix was achieved in the presence of MAPE. HDPE/POF/MAPE composites achieved the highest tensile modulus and strength with 40% POF. But lower thermal stability, ductility and impact strength were found with the addition of the POF. However, the thermal stability, crystallinity, ductility and toughness improved in HDPE/POF/DPS/MAPE hybrid composites due to the addition of DPS or the substitution of POF by DPS.
h i g h l i g h t s Review on bioremediation of treated wood. Conceptualization of bioremediation... more h i g h l i g h t s Review on bioremediation of treated wood. Conceptualization of bioremediation into direct and indirect microbial remediation. The combination of direct and indirect bioremediation is a promising decontamination approach. Alternatives and reuse of detoxified wood after bioremediation are detailed. Challenges and prospects of bioremediation of contaminated wood are discussed.
We investigated the effects of polymer blend variation on the physical, mechanical, and thermal p... more We investigated the effects of polymer blend variation on the physical, mechanical, and thermal properties of wood-polymer composites (WPC). We used high-density polyethylene (HDPE) and polypropylene (PP) and a combination of 80% PP, 20% HDPE, and 80% HDPE, 20% PP as polymer blends for WPC formulations to simulate recycled plastics. We used black spruce (Picea mariana Mill.) hammer milled fibers (75–250 μm) at 35 wt% as a filler for all the formulations. A two-step process was used for WPC manufacturing; pellet extrusion followed by test samples injection. Tensile and three bending tests characterized the WPC mechanical properties. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) characterized the WPCs’ thermal properties. Water absorption and contact angle measurements assessed the composite dimensional stability. Infrared spectroscopy (FTIR) and electron scanning microscopy (SEM) investigated the WPCs’ surface chemistry and microstructure. Mechanical pr...
This study aims to investigate the feasibility of producing OSB from softwood species used in the... more This study aims to investigate the feasibility of producing OSB from softwood species used in the Eastern Canadian softwood lumber industry in the context of the overcapacity of softwood chips traditionally produced for the pulp and paper industry. Balsam fir, black spruce, and jack pine logs were used to make 15 mm thick OSB panels with a target density of 600 kg/m3. The panels were manufactured at a temperature of 210 °C during a pressing cycle of 300 s. Strands with different thicknesses were used to obtain a constant specific surface of 6.7 m2/kg for the three species. The bending modulus of the rupture and modulus of elasticity, internal bond, and thickness swelling of the OSB panels were determined and compared to the CSA standard requirements. The species significantly affected the physical and mechanical properties of OSB. The bending properties of OSB decreased with an increase in the species wood density. The internal bond strength of OSB increased with the increase in spe...
To better understand the genetic control of growth and wood properties in the hybrid poplar (Popu... more To better understand the genetic control of growth and wood properties in the hybrid poplar (Populus spp.), genetic relationships of selected wood properties with growth traits were examined in a 3-yr-old clonal trial located in Windsor and St-Ours, southern Quebec, Canada. In total, 371 trees from 21 hybrid poplar clones were sampled at the two locations. Clone effects are stronger than growth traits effects on wood density and initial moisture content. The estimated clonal repeatability for wood density (0.92) and initial moisture content (0.80) across the two sites are thus considerably higher than for dbh (0.64) and tree height (0.72). Neither wood density nor mean fiber length were found to significantly correlate with growth traits. This suggests that in the hybrid poplar clones selection for growth traits will not result in a significant reduction in the wood quality traits. Selection for stem dry fiber weight appears to be an optimal selection strategy, as it will lead to the highest genetic gain in stem dry fiber yield, or maximum fiber production while wood density is improved. FOR. SCI. 49(6):00-00.
Estimations of transition age (TA) and juvenile wood proportion (JWP) are important for wood indu... more Estimations of transition age (TA) and juvenile wood proportion (JWP) are important for wood industries due to their impact on end-product quality. However, the relationships between analytical determination of TA based on tracheid length (TL) and recognized thresholds for adequate end products have not yet been established. In this study, we used three different statistical models to estimate TA in white spruce (Picea glauca (Moench) Voss) based on TL radial variation. We compared the results with technological maturity. A two-millimeter threshold, previously suggested for good paper tear strength, was used. Tracheid length increased from pith to bark and from breast height to upper height. Juvenile wood (JW) was conical with the three models. At breast height, TA ranged from 11 to 27 years and JWP ranged from 15.3% to 47.5% across the three models. The linear mixed
Flavia Lega Braghiroli, Research Forest Institute (RFI), University of Québec in Abitibi-Témiscam... more Flavia Lega Braghiroli, Research Forest Institute (RFI), University of Québec in Abitibi-Témiscamingue (UQAT), 445 Boul. de l’Université, Rouyn-Noranda, Québec, QC J9X 5E4, Canada [email protected]; [email protected] Hassine Bouafif, Technology Center for Industrial Waste (CTRI), Cégep de l’Abitibi-Témiscamingue (College of Abitibi-Témiscamingue), 425 Boul. du Collège Rouyn-Noranda, QC J9X 5E5, Canada Carmen Mihaela Neculita, Research Institute on Mines and the Environment (RIME), University of Québec in Abitibi-Témiscamingue (UQAT), 445 Boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada Ahmed Koubaa, Research Forest Institute (RFI), University of Québec in Abitibi-Témiscamingue (UQAT), 445 Boul. de l’Université, Rouyn-Noranda, Québec, QC J9X 5E4, Canada
Abstract The project aims to develop cellulose in new biocomposites to produce dielectric materia... more Abstract The project aims to develop cellulose in new biocomposites to produce dielectric materials based on thermoplastic matrices. Cellulose fibers bring multiple advantages to thermoplastic matrices in mechanical, physicochemical, thermal, and dielectric properties. Although these biocomposites are known for their advanced mechanical properties, only a few studies investigated their dielectric behavior and the effect of cellulose fibers on these properties. The bio-based composites must have better dielectric properties and excellent ductility to use as insulators in electrical cables. Thus, we investigated the dielectric properties (dielectric constant (e’), loss factor (e’’), conductivity (σ) and resistivity (ρ)) of high-density polyethylene (HDPE) and cellulose fibers composites. Results prove that the addition of cellulosic fibers increased the dielectric constant, the loss factor, and the conductivity of the materials compared to the neat polymer. Composites with 50 wt% fiber content showed the highest values. Therefore, the volume resistivity of all the composites studied decreased with frequency and fiber content. In addition, the reinforced polymer exhibited an intermediate thermal behavior between the polymer and the fibers. Thus, they are thermally stable materials up to 320 °C.
In this study, activated biochar was produced using pilot-scale technologies of fast pyrolysis an... more In this study, activated biochar was produced using pilot-scale technologies of fast pyrolysis and activation to create desirable morphology, surface chemistry, and adsorptive properties for application in supercapacitors. First, residues from white birch were converted into biochar by fast pyrolysis (~ 450 °C). Then, physical (using CO2) or chemical (using KOH) activation was carried out in a homemade pilot-scale furnace at 900 °C. These synthesized materials presented distinct porosity structures: micro-/mesoporous (CO2 material) and highly microporous (KOH material), reaching surface areas of up to 1700 m 2 g-1. Electrochemical results showed that KOH-activated biochar had higher specific electrical capacitance in both acidic and neutral electrolytes with a maximum specific capacitance value of 350 and 118 F g-1 at 1 A g-1 , respectively; while, for CO2activated biochar, the maximum obtained values were 204 and 14 F g-1. The greater proportion of oxygenated and nitrogenated functional groups on the surface of the KOH activated biochar, along with its high surface area (with wider porosity), improved its performance as a supercapacitor electrode. Specifically, the low proportion of ultramicropores was determinant for its better electrochemical behavior, especially in the neutral electrolyte. Indeed, these results are similar to those found in the literature on the electrical capacitance of carbonaceous materials synthesized in a small-scale furnace. Thus, the chemical-activated biochar made from wood residues in pilot-scale furnaces is a promising material for use as electrodes for supercapacitors.
Continuous-fiber reinforced WPCs were prepared using an extruder with a special die. The effects ... more Continuous-fiber reinforced WPCs were prepared using an extruder with a special die. The effects of the amount (1 to 7 bundles) and type of fiber (aramid rovings and yarns and carbon and glass yarns) on the mechanical properties of WPCs were studied. The adding of continuous fibers led the tensile, flexural and impact strength of the composites to increase by up to 47.3%, 83.1% and 713.4%, respectively. The damping ratio analysis revealed that the interfacial bonding of glass-yarn reinforced WPCs was the best among the tested samples. Adding continuous fibers to WPCs at a low volume fraction can promote their use as load-bearing engineered materials.
Herein, Ti 3 C 2 T x (MXene) was synthesized and mixed with polyvinyl alcohol (PVA) to fabricate ... more Herein, Ti 3 C 2 T x (MXene) was synthesized and mixed with polyvinyl alcohol (PVA) to fabricate PVA/MXene nanocomposites. The results confirmed that delaminated MXene was successfully synthesized. The nanocomposites were obtained via casting/evaporation method. The thermal stability was evaluated by thermogravimetric analysis (TGA). For the PVA composites with content of 2 wt% MXene (PVA-MXene2), the thermal decomposition was retarded by approximately 20 C when the temperature was lower than 350 C compared with that of pure PVA. Moreover, the evolved gas products of the PVA/MXene composite were lower than those of pure PVA. For the first time, the flame retardancy of PVA/MXene nanocomposite was investigated using a microscale combustion calorimeter. The peak heat release rate (PHRR) and total heat release of the PVA composite were reduced by 25.7% and 25.5%, respectively, with 1 wt% of MXene. The temperatures at PHRR of PVA/MXene composites were improved with the addition of MXene. Moreover, the addition of MXene resulted in PVA composites with a higher tensile strength and elongation at break than those of a pure PVA film. The improvements in the flame retardancy, thermal and mechanical properties of PVA/MXene composites should enable a wide range of potential applications of MXenes in polymer matrices.
SO2, one of the most harmful gases, is generated when oxygen in air combines with sulfur species ... more SO2, one of the most harmful gases, is generated when oxygen in air combines with sulfur species from anthropogenic sources (e.g., the smelting of mineral ores). Thus, the objectives of this study are to assess the potential use of activated biochar for the removal of SO2, and to compare the impact of the activation process on the development of porosity and surface chemistry for SO2 adsorption. Results show that activated biochars develop porosity (with narrow and wide pores) and functional groups connected to their surface, which makes these materials suitable for adsorption of SO2. However, no linear relationship between textural properties and the amount of SO2 adsorbed by activated biochars from dynamic adsorption tests were noticed. In addition, the highest SO2 adsorption capacity was not reached for materials with the highest surface area, or micropore or ultramicropore volume. Specifically, steam-activated biochar had the best performance for the removal of SO2 due to its optimal surface area (590 m 2 g-1); volume of ultra-(0.22 cm 3 g-1), micro-(0.23 cm 3 g-1), and mesopores (0.11 cm 3 g-1); its basic character (not from nitrogenated groups); and the low percentage of acid-oxygenated functional groups connected to its surface. After six thermal regeneration cycles, activated biochar exhibited high SO2 removal capacity and high regenerability. Based on these findings, activated biochar made from forest wood residues has promising potential for the removal of gas contaminants.
Fifteen stems of jack pine (Pinus banksiana Lamb.) coming from three commercial thinned (CT) plot... more Fifteen stems of jack pine (Pinus banksiana Lamb.) coming from three commercial thinned (CT) plots (control, moderate, and intensive thinning) in the Abitibi-Témiscamingue region, Canada, were cross-cut into three 2.4 m length sections: bottom, middle, and top logs. Logs were processed with a chipper-canter at three cutting widths (CW 12.7, 19.1, and 25.4 mm), producing chips and a three faced cant. Chips were assessed by thickness, width, and length. Knot characteristics [total knot number (TKN) and area (TKA)] were assessed in the three cant faces. Growth ring attributes [earlywood density, latewood density (LWD), ring density (RD), earlywood proportion (EWP), ring width, and rings per mm], mechanical properties (shear, splitting, modulus of elasticity and modulus of rupture in bending), and basic density were evaluated on samples obtained within each CW area. The weighted mean chip thickness (WCT) was significantly affected by the log position in the stem (LPS) and CW. WCT increased as CW increased. Jack pine produce thicker chips than black spruce, when processed under the same cutting parameters. Thickness of chips coming from bottom and middle logs was similar due to a greater taper of the bottom log, which slightly increased this dimension. Thickest chips were produced in the top log due to a higher TKA and TKN towards the top of the stem. Multiple linear regressions showed that TKA, CW, and RD were significant predictors of WCT. Chip size distributions were significantly affected by the CT, LPS, and CW. Thinned stands logs appeared to produce smaller chips than natural stand logs. Moreover, chip thickness distribution was affected primarily by TKA and EWP, while the width and length distribution was mainly affected by EWP, LWD, and TKN. Chip size in jack pine is to some degree determined by knot attributes, growth ring characteristics, and wood density of the raw material. These results suggest the potential advantage of sorting logs prior to chipping, either by species, LPS and/or provenance (thinned or natural stands).
Abstract The aim of this study was to improve performance of a vegetable oil-based coating with a... more Abstract The aim of this study was to improve performance of a vegetable oil-based coating with addition of nanoparticles. Uniform distribution of added nanoclay, nanosilica and nanoalumina is the key to ensure the increased abrasion resistance. A high speed mixer, bead mill and ultrasonic mixer were used to disperse the nanoparticles into coatings. The quality of nanoparticle dispersion in liquid coating was studied by dynamic light scattering (DLS), and in dry film by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Using a high-speed mixer with addition of glass beads resulted in exceptional dispersion of nanoparticles in coating as confirmed by the above techniques. Although, addition of nanoclay had a positive effect on drying time of coating (reducing it by 37%), it had negative effects on viscosity (increasing it by 5 times). Overall, addition of 1% nanoparticles significantly increased the abrasion resistance of modified coating after 2000 abrasion cycles in comparison with pure unmodified coatings as applied on larch wood flooring samples.
Chromated copper arsenate-treated (cca) wood disposal faces environmental restrictions due to its... more Chromated copper arsenate-treated (cca) wood disposal faces environmental restrictions due to its toxicity, heavy metal leaching in storage sites, and greenhouse gas emissions during incineration. Thus, finding new management methods for this contaminated wood at the end of life is crucial. This study evaluated the effect of pyrolysis temperature (300, 400, and 500 °C), particle size, biochar yield, and the behavior of arsenic (As), chromium (Cr), and copper (Cu) during treated-wood pyrolysis. The highest biochar yield was obtained at 300 °C for fine particles. The biochar retention of heavy metals decreased with increasing pyrolysis temperature. At 300 °C, the highest biochar As, Cr, and Cu retentions were 76, 91, and 83%. At 500 °C, biochar only retained 43% of the As. Additionally, heavy metal leaching from the biochar exceeded the Environmental Protection Agency’s (EPA) maximum concentration limit of 5 mg/L. High-density polyethylene encapsulation of contaminated biochar reduced...
The flame retardancy of wood–polymer composites significantly affects their potential application... more The flame retardancy of wood–polymer composites significantly affects their potential applications. Thus, multilayered wood flour/high-density polyethylene (HDPE)/polycarbonate (PC) composites were prepared via thermocompression to improve the fire retardancy of wood–polymer composites in this paper. Thermal degradation behavior, flame retardancy, and flexural strengths of the resulting composites were investigated using a thermogravimetric analysis, cone calorimetry, and mechanical testing machine, respectively. Results revealed that the boric acid treatment reduced the heat release rate and total heat release of the wood flour/HDPE composites and increased their mass of residues. However, boric acid reduced the flexural strength of the resulting composites. The combustion test indicated that PC cap layers suppressed the combustion of the resulting composites via the formation of carbon layers. Adding PC layers reduced heat release and increased the flexural strength of the resulti...
Biochar is a carbon-rich organic material that has advantageous physicochemical properties for ap... more Biochar is a carbon-rich organic material that has advantageous physicochemical properties for applications in multidisciplinary areas of science and engineering, including soil amendment, carbon sequestration, bioenergy production, and site rehabilitation. However, the typically low porosity and surface area of biochars (from 0.1 to 500 m 2 g-1) limits the suitability for other applications, such as catalysis, electrochemistry, energy storage, and contaminant sorption in drinking water and wastewater. Given the high global demand for activated carbon products, scientists and industrialists are exploring the potential of biochar-derived biomass as precursors for activated carbons. This review presents and discusses the available studies on activated biochars produced from various precursor feedstocks and under different operating conditions in a two-step procedure: pyro-gasification (torrefaction, slow to flash pyrolysis, and gasification) followed by activation (physical, chemical or physicochemical). Findings from several case studies demonstrate that lignocellulosic residues provide attractive precursors, and that chemical activation of the derived biochars at high temperature and long residence time produces highly porous end materials. Indeed, the porosity of activated biochars varies greatly (from 200 to 2500 m 2 g-1), depending on the pyro-gasification operating conditions and the feedstock (different feedstocks have distinct morphological and chemical structures). The results also indicate that the development of highly porous activated biochars for diverse purposes (e.g., electrodes for electrochemical energy storage devices, catalyst supports and adsorbents for water treatment) would benefit both the bioeconomy and the environment. Notably, it would leverage the potential of added-value biomass as an economical, non-fossil, readily available, and renewable energy source.
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Papers by Ahmed Koubaa