Mihai M.,Industrial Materials Institute of Canada |
Legros N.,Industrial Materials Institute of Canada |
Iordan A.,Industrial Materials Institute of Canada |
Alemdar A.,19 rue Franquet
Annual Technical Conference - ANTEC, Conference Proceedings | Year: 2011
This paper aims at developing natural fiber biocomposites based on biopolymers reinforced with wood fibers obtained from a thermo-mechanical refining process. Polylactide (PLA) and polylactide/thermoplastic starch blends (PLA/TPS) were used as matrices. TPS content in the PLA/TPS blends was set at 50 wt%. Two wood fiber types were selected, a hardwood (HW) and a softwood (SW), to state the effect of the fiber type on the biocomposite properties. The impact of different additives on biocomposite properties was studied with the purpose to enhance the biopolymer-wood fiber affinity giving the best final mechanical performance. Biocomposites containing 30 wt% of wood fibers were obtained by co-rotating twin-screw extrusion. The properties are described in terms of morphology, thermal, rheological, and mechanical properties.
Landry V.,19 rue Franquet |
Blanchet P.,19 rue Franquet
Progress in Organic Coatings | Year: 2012
PVDF-acrylic opaque coating systems were applied onto two different wood species; Black spruce and White pine. Weathering resistance of these products was compared to the one of industrial water-based acrylic coatings used for exterior siding. ATR-FTIR results have shown that the PVDF portion of the coatings resist easily to the UV light, even at the extreme surface. At the opposite, the acrylic portion of the coatings was strongly affected by the UV light. This degradation has led to significant color change. Contact angles were also measured before and after the accelerated aging test in order to assess the recoatability of these coatings. Wettability was found to be slightly lower for the PVDF-acrylic coatings. The morphology of the different coating systems was finally assessed. Results have shown that the PVDF-acrylic coatings are strongly affected by the White pine resin exudation. © 2012 Published by Elsevier B.V. All rights reserved.
Fu S.,Northeast Forestry University |
Han G.,Northeast Forestry University |
Cheng W.,Northeast Forestry University |
Deng J.,19 rue Franquet
Advanced Materials Research | Year: 2011
Particleboards bonded with urea formaldehyde (UF) and a combination of UF and methylene diphenyl diisocyanate (MDI) resins were manufactured using wheat straws modified through different steam explosion treatments. The effect of steam explosion treatment, resin system, and mixing ratios of wood and straw materials on the panel properties was investigated. Generally, with steam explosion treatment of straw fibers, panel properties in bending and internal bond (IB) strength increased, thickness swelling (TS) and water absorption (WA) decreased. The bending properties for the panels made from the straws pretreated with 12 h water-soaking were significantly improved at the UF/MDI content level of 5%/1%. The IB strength dramatically increased, while TS and WA decreased with the use of dual resins. With increased weight ratio of wheat straw to wood particles, the bending properties, IB strength, TS and WA deteriorated. Pure wheat straw boards had the lowest properties. Wood particles in substitution for part of straw materials helped improve the panel properties. The results demonstrated that steam explosion modification and/or its combination with UF/MDI dual resin system can be a feasible approach to improve the bonding strength for wheat straw based particleboards. © (2011) Trans Tech Publications.
Landry V.,19 rue Franquet |
Blanchet P.,19 rue Franquet |
Zotig L.,Societe Laurentide |
Martel T.,19 rue Franquet
Journal of Coatings Technology Research | Year: 2013
The purpose of this study was to investigate the performance of a semitransparent PVDF-acrylic coating on two wood species: Black spruce and White pine. An accelerated aging test was performed on the PVDF-acrylic coating and the results obtained were compared with those obtained for a water-based acrylic coating. Color changes were found to be more significant for the acrylic coating, especially after 1000 h of exposure, and for the White pine panels. Infrared spectroscopy revealed that the acrylic resin was more affected by the accelerated aging test than the PVDF resin, although X-ray photoelectron spectroscopy revealed that PVDF was slightly affected at the extreme surface (first 10 nm). Star-shaped defects were found at the surface of the White pine panels finished with the PVDF-acrylic coating. Experiments revealed that the PVDF-acrylic coating does not seem to be flexible enough to sustain resin exudation or other stresses. © 2012 ACA and OCCA.
Migneault S.,Laval University |
Koubaa A.,University of Québec |
Nadji H.,University of Québec |
Riedl B.,Laval University |
And 2 more authors.
Wood and Fiber Science | Year: 2010
Pulp and paper sludge can be recycled in the manufacture of medium-density fiberboard (MDF) because it contains wood fibers. A comparative study was conducted to evaluate the properties of MDF made from virgin fibers mixed with different pulp and paper sludge sources. A factorial design was used in which factors were mill pulping processes, thermal-mechanical pulping (TMP), chemical-thermal- mechanical pulping (CTMP), and kraft pulping, and percentage of sludge mixed with virgin fibers (0, 25, 50, and 75%). Virgin fibers were obtained from paper birch wood, an underutilized species. Chemical composition, physical characteristics, pH, and buffer capacity of sludge were measured. MDF properties decreased mostly linearly with sludge content. Panel properties negatively correlated with the proportion of nonfibrous material such as ash and extractives. TMP and CTMP sludge sources produced panels of similar quality, and kraft sludge produced the lowest quality. It was concluded that the amount of sludge that can be incorporated into MDF without excessive decrease in panel quality depends on the pulping process. At 25% sludge content, all panels met ANSI quality requirements for MDF used for interior applications. © 2010 by the Society of Wood Science and Technology.
Wang M.,University of Alberta |
Li N.,University of Alberta |
Choi P.,University of Alberta |
Zhang Y.,19 rue Franquet
Canadian Journal of Chemistry | Year: 2010
The relative concentrations of tie chains (TCs) in six single-site linear low-density polyethylene blown films (LLDPE) were measured using a polarized Fourier transform infrared (FTTR) technique along with a newly developed sample preparation strategy. Before the FTIR measurements, the films were first subjected to a tensile strain of 20% using a homemade appliance and then annealed at a temperature of 60 °C over a time period of 24 h to relax all nonTCs in the amorphous phase. The relative TC concentrations were inferred from the FTIR measurement of the orientation order of the amorphous chains in the stretched films. It is believed that a greater concentration of TCs leads to a higher orientation order for the amorphous chains. The results showed that the quantity of TCs is essentially determined by the chains with the appropriate branch frequency (∼12 branches per 1000 backbone carbons based upon the films used in this work), especially those of the high molar mass chains as formation of TCs requires suitable ethylene sequence lengths between branches. The dart impact strength of the films appeared to be positively related to the relative concentration of TCs; films with greater concentrations showed higher dart impact strength. No clear correlations were observed between the relative concentration of TCs and the tear resistance of the films. However, the TC concentration seems to be related to the magnitude of the difference between the transverse direction and machine direction tear resistance.
Busnel F.,Laval University |
Blanchard V.,19 rue Franquet |
Pregent J.,University of Montréal |
Stafford L.,University of Montréal |
And 3 more authors.
Journal of Adhesion Science and Technology | Year: 2010
This work examines the adhesion properties of sugar maple (Acer saccharum) and black spruce (Picea mariana) wood surfaces following their exposure to a dielectric barrier discharge at atmospheric pressure. Freshly sanded wood samples were treated in Ar, O2, N2 and CO 2-containing plasmas and then coated with a waterborne urethane/acrylate coating. In the case of black spruce wood, pull-off tests showed adhesion improvement up to 35% after exposure to a N2/O 2 (1:2) plasma for 1 s. For the same exposure time, adhesion improvements on sugar maple wood up to ∼25% were obtained in Ar/O 2 (1:1) and CO2/N2 (1:1) plasma mixtures. Analysis of the wettability with water contact angle measurements indicate that the experimental conditions leading to adhesion improvement are those producing more hydrophobic wood surfaces. In the case of sugar maple samples, X-ray photoelectron spectroscopy investigations of the near-surface chemical composition indicate an increase of the O/C ratio due to the formation of functional groups after exposure to oxygen-containing plasmas. It is believed that a combination of structural change (induced by UV radiation, metastable particles impingement, or both) and chemical change due to surface oxidation is responsible for the observed surface modification of black spruce and sugar maple wood samples. © 2010 Koninklijke Brill NV, Leiden.
Migneault S.,Laval University |
Koubaa A.,University of Québec |
Nadji H.,Laval University |
Deng J.,19 rue Franquet |
Zhang S.Y.,665 East Mall
Wood and Fiber Science | Year: 2011
Pulp and paper sludge is valuable in fiberboard manufacturing because primary sludge (PS) contains fibers and secondary sludge (SS) has adhesive properties. We evaluated properties of binderless fiberboard made from conventional pulp and paper mill sludge sources using a factorial design in which the factors were SS:PS ratio (1:9, 2:8, and 3:7) and pulping process (thermomechanical [TMP], chemical- thermomechanical [CTMP], and kraft). Sludge was collected, refined, dried, and characterized for chemical composition and fiber length. Internal bond strength of CTMP panels increased 90% and thicknessswell of TMP panels improved 92% with increasing SS content from 10-30%. IR Fourier transform and X-ray photoelectron spectroscopy analyses were conducted to better understand these results. Increased bonding was attributed to presence of proteins and lignin on the sludge fiber surface, which enhanced adhesion during hot pressing, whereas surface contamination decreased bonding efficiency. The TMP formulation at SS:PS ratio 3:7 met the ANSI requirement for basic hardboard. All other formulations were not dimensionally stable enough to meet the standard. The CTMP source resulted in the highest mechanical properties, and thickness swell was similar for the TMP and CTMP pulping processes. The kraft source produced low-integrity and dimensionally unstable panels. © 2011 by the Society of Wood Science and Technology.