8 research outputs found
Valorisation des résidus d'écorce de bouleau blanc (Betula papyrifera) sous forme de fabrication de panneaux
Des 3 500 000 tonnes mĂ©triques anhydres (TMA) dâĂ©corces produites en 2004 par lâindustrie forestiĂšre au QuĂ©bec, 96 000 (soit 2,7% de la masse totale des Ă©corces produites la mĂȘme annĂ©e) Ă©taient celles de bouleau blanc. Ces Ă©corces sont en grande partie utilisĂ©es dans la production dâĂ©nergie alors quâelles gĂ©nĂ©reraient plus de gains si elles Ă©taient utilisĂ©es pour la fabrication de panneaux agglomĂ©rĂ©s. Lâobjectif de ce projet de recherche est de mettre sur pied des stratĂ©gies permettant dâutiliser efficacement les particules dâĂ©corce de bouleau pour fabriquer diffĂ©rents types de panneaux de masse volumique moyenne qui satisfont les exigences de la norme des panneaux conventionnels. Les essais prĂ©liminaires ont laissĂ© entrevoir quâil Ă©tait difficile de fabriquer les panneaux de masse volumique moyenne exclusivement Ă base de ces particules dâĂ©corce, Ă cause de leur faible taux de cellulose, surtout dans les particules dâĂ©corce externe qui ne fait pas dâelles une matiĂšre structurale comme le bois. En outre, la forme granuleuse de la partie interne de cette Ă©corce ne favorise pas lâeffet dâentrelacement qui contribue fortement Ă lâamĂ©lioration des propriĂ©tĂ©s de flexion des panneaux. Ăgalement, la forte concentration des subĂ©rines dans la partie externe de cette Ă©corce la rend trĂšs hydrophobe et sa surface est comme celle du tĂ©flon, c'est-Ă -dire, trĂšs difficile Ă mouiller. Les parties externe et interne de cette Ă©corce ont des propriĂ©tĂ©s diffĂ©rentes, et pour pallier ces difficultĂ©s, la solution idĂ©ale consistait Ă concevoir des panneaux mixtes oĂč ces particules dâĂ©corce seraient renforcĂ©es avec les particules, les fibres et les lamelles de bois. Le premier type de panneau mis sur pied est fait dâun mĂ©lange de fibres de bois et de particules dâĂ©corce interne de bouleau blanc dans la couche mĂ©diane et de fibres de bois dans les couches couvrantes. Le pourcentage de fibres de bois (deux niveaux) et le pourcentage de fibres de bois ajoutĂ©es aux particules dâĂ©corce interne de la couche mĂ©diane (trois niveaux) constituaient les deux facteurs du dispositif utilisĂ© pour la fabrication de ce type de panneaux. Les panneaux fabriquĂ©s ont tous eu des propriĂ©tĂ©s mĂ©caniques qui rencontraient les exigences de la norme, le panneau avec 25% de fibres de bois dans les couches couvrantes et 9% de fibres de bois ajoutĂ©es aux particules dâĂ©corce de la couche mĂ©diane ont eu les meilleurs propriĂ©tĂ©s mĂ©caniques alors que le panneau le plus stable dimensionnellement est celui avec 22% de fibres de bois dans les couches couvrantes et 5% de fibres de bois mĂ©langĂ©es aux particules dâĂ©corce de la couche mĂ©diane. Quant au second type de panneau, il est constituĂ© de particules dâĂ©corce externe de bouleau blanc dans les couches couvrantes et respectivement de particules et de fibres de bois dans la couche mĂ©diane. Les deux facteurs intervenant dans sa fabrication sont le type de matĂ©riel dans la couche mĂ©diane (particules de bois versus fibres de bois) et le pourcentage de particules dâĂ©corce dans les couches couvrantes. La mĂ©thode dâanalyse statistique utilisĂ©e a permis de sĂ©lectionner le panneau avec 45% de particules dâĂ©corce externe de bouleau dans les couches couvrantes et les particules de bois dans la couche mĂ©diane comme le meilleur du groupe, surtout en se basant sur le critĂšre de la stabilitĂ© dimensionnelle mesurĂ©e par la dilatation linĂ©aire. Le troisiĂšme type de panneau est un panneau sous-plancher de 8 mm dâĂ©paisseur et densifiĂ© Ă 800 kg/m3. Il est constituĂ© de particules dâĂ©corce externe de bouleau dans les couches couvrantes et de particules de bois dans la couche mĂ©diane. Les deux facteurs utilisĂ©s pour sa conception sont : le pourcentage de la rĂ©sine phĂ©nol-formaldĂ©hyde (PF) utilisĂ©e pour encoller les particules dâĂ©corce des couches couvrantes (trois niveaux de pourcentage) et le traitement des particules dâĂ©corce utilisĂ©es (Ă©corce non traitĂ©e Ă la soude versus Ă©corce traitĂ©e Ă la soude). Les particules dâĂ©corce sont traitĂ©es afin de mettre en Ă©vidence leur impact sur les propriĂ©tĂ©s des panneaux produits. Le traitement Ă la soude a diminuĂ© les propriĂ©tĂ©s des panneaux produits en affaiblissant les structures de lâĂ©corce externe de bouleau. Le meilleur panneau du groupe est celui dont les particules dâĂ©corce externe de bouleau non traitĂ©es Ă la soude sont encollĂ©es avec le plus bas pourcentage de rĂ©sine PF. Le dernier type de panneau concerne un panneau mixte avec les particules dâĂ©corce externe de bouleau blanc au centre et les lamelles de bois dans les couches couvrantes. Deux facteurs sont utilisĂ©s dans sa mise en place : lâorientation des lamelles dans les couches couvrantes (orientĂ©es versus non orientĂ©es) et le type de matĂ©riel dans la couche mĂ©diane (Ă©corce non traitĂ©e Ă la soude, Ă©corce non traitĂ©e Ă la soude plus 10% de fibres de bois, Ă©corce traitĂ©e Ă la soude). Le traitement Ă la soude nâa pas produit les effets escomptĂ©s (amĂ©lioration des propriĂ©tĂ©s mĂ©caniques). Lâanalyse statistique utilisĂ©e dans un plan factoriel en blocs complets a permis de dĂ©terminer le meilleur panneau comme Ă©tant celui avec les particules dâĂ©corce non traitĂ©es Ă la soude et sans ajout de fibres de bois. La mĂ©thode mise sur pied pour les fabrications des quatre types de panneaux mixtes susmentionnĂ©s permet de valoriser plus de 50% (par rapport Ă la masse anhydre totale des particules utilisĂ©es pour fabriquer le panneau) de particules dâĂ©corce de bouleau blanc par panneau fabriquĂ©, ce qui conforte lâidĂ©e dâemployer de façon judicieuse cette Ă©corce comme source alternative dâapprovisionnement en matiĂšre premiĂšre pour les usines de panneaux.In the year 2004 alone, 96 000 dry metric tons (DMT) of white birch bark were produced by forest industries in Quebec. This constituted approximately 2.7% of total bark production for the region. These barks which are mostly used for energy production would have generated more benefits had they been used for agglomerated panels manufacture. The objective of this research project was to set up strategies which will make possible to effectively use bark particles of white birch, for the manufacture of various types of medium density panels that meet the standard requirements of particleboards. The preliminary tests revealed that, it was difficult to manufacture medium density panels based on bark particles exclusively, due to the following disadvantages. (1): their low cellulose content, especially on the outer bark particles, does not make them a structural material like wood; (2): the granular form of the inner bark does not contribute to the interlacing effects, which strongly contribute to the improvement of panels bending properties; (3): the high concentration of suberins on the outer bark makes it very hydrophobic with a surface similar to teflon which is very difficult to wet; and (4): the outer and inner parts barks have different properties. In the face of such difficulties, the ideal solution consisted in designing mixed panels where these bark particles will be reinforced with wood particles, wood fibres and wood strands. The first panel type was set up - a mixed panel with wood fibres in the surface layers, and a mixture of wood fibres and inner bark particles of white birch in the core layer. The percentage of wood fibres (two levels) and the percentage of wood fibres added to the inner bark particles in the core layer (three levels) were the two panels manufacturing factors. All manufactured panels fulfilled the standard requirements for all mechanical properties. Panel with 25% wood fibres in the surface layers and 9% wood fibres mixed with bark particles in the core layer had the best mechanical properties, while panel with 22% wood fibres in the surface layers and 5% wood fibres mixed with bark particles in the core layer was the most dimensionally stable. The second panel type is composed of outer bark particles of white birch in the surface layers and wood material in the core layer. The two manufacturing factors were: the type of wood material in the core layer (wood particles versus wood fibres) and the percentage of outer bark particles in the surface layers. The statistical analysis method used made possible to select the panel with 45% outer bark particles of white birch in the surface layers and wood particles in the core layer as the best, especially by taking into account the dimensional stability criterion based on linear expansion measurement. The third panel type was a sub-flooring panel with a thickness of 8 mm and a density of 800 kg/m3. It was composed of outer bark particles in the surface layers and wood particles in the core layer. The two factors used for its experimental design were: the percentage of phenol-formaldehyde resin (PF) used to bond bark particles of surface layers (three levels of percentage) and the treatment of bark particles used (untreated bark versus bark treated with soda). The bark particles were treated in order to highlight their impact on the properties of manufactured panels. The alkali treatment lowered the properties of manufactured panels because soda treatment weakened the structures of outer bark particles of white birch used. The best panel was that with untreated outer bark particles of white birch, bonded with the lowest percentage of PF (5%). The last panel type was a mixed panel with outer bark particles of white birch in the core layer and wood strands in the surface layers. Two factors were used in its setting-up: the orientation of strands in the surface layers (oriented versus not non oriented) and the type of material in core layer (untreated bark particles, a mix of untreated bark particle and 10% wood fibres, bark particle treated with soda). The alkali treatment did not produce the expected effects (improvement of panelsâ mechanical properties). The statistical analysis used in a factorial design in complete blocks made possible to choose the panel with untreated outer bark particles without wood fibres addition as the best. The method used to manufacture the above-mentioned mixed panels permitted to add higher proportion of white birch bark particles in each manufactured panel. The result of the present research project demonstrates that, bark particles of white birch, could be an alternative source of raw material supply for wood-based composite mills
Propiedades fĂsicas y mecĂĄnicas de paneles a base de partĂculas de corteza externa de abeto blanco: Mezcla de paneles con partĂculas de madera versus fibra de madera
El uso de la corteza externa de abeto blanco en la fabricaciĂłn de canoas por las primeras naciones de CanadĂĄ es un ejemplo de su uso mĂĄs antiguo. Esto confirma sus caracterĂsticas hidrĂłfugas, la cual puede ser explotada mediante su uso en la superficie del panel compuesto de 3 capas para protegerlo de filtraciones de humedad. Estos tableros fueron fabricados con partĂculas de corteza externa en las capas superficiales, y con partĂculas gruesas o fibras de madera en el corazĂłn. Un experimento factorial en un diseño de bloque completo hizo posible realizar el diseño de experimento. Los dos grandes factores considerados, fueron el porcentaje de corteza en las capas superficiales con 3 niveles y el tipo de material usado en el corazĂłn, con dos niveles respectivamente (partĂculas y fibras de madera). Cuatro rĂ©plicas fueron hechas para cada panel. SĂłlo los tableros con partĂculas gruesas de madera en el corazĂłn pasaron todas las pruebas fĂsicas satisfaciendo los requerimientos del interior de los tableros de partĂculas. Paneles con 45% de partĂculas de corteza en la superficie y 55% de partĂculas de madera en el corazĂłn fueron seleccionados como los mejores, debido a su buena estabilidad dimensional. AbstractThe use of outer white birch bark in canoes is an example of its oldest use by the first nations in Canada. This use confirms the hydrophobic characteristics of this bark, which can be capitalized on by using it in the outer layers of three-layer mixed composite panels in order to protect them from water infiltration from their surface. These panels were made up of outer white birch bark particles in the surface layers with coarse wood particles or wood fibres in the core layer. A factorial experiment used in a complete block design permitted to carry a suitable statistical analysis of measured properties. The two main considered factors were respectively the bark percentages in the surface layers with three levels and the type of material used in the core with two levels. Four replicates were done for each panel. The panels with wood particles in the core layer gave physical and mechanical properties satisfying the indoor requirements for particleboards and those with wood fibres in the core layer passed the requirement of medium fibres density board. Panel with 45% bark particles in the surface and 55% wood particles in the core was selected as the best because of its good dimensional stability
PropriĂ©tĂ©s des panneaux dâĂ©corce externe de bouleau blanc (Betula papyrifera) avec renfort de particules grossiĂšres de bois dans la couche mĂ©diane
PHYSICAL AND MECHANICAL PROPERTIES OF PANEL BASED ON OUTER BARK PARTICLES OF WHITE BIRCH: MIXED PANELS WITH WOOD PARTICLES VERSUS WOOD FIBRES
The use of outer white birch bark in canoes is an example of its oldest use by the first nations in Canada. This use confirms the hydrophobic characteristics of this bark, which can be capitalized on by using it in the outer layers of three-layer mixed composite panels in order to protect them from water infiltration from their surface. These panels were made up of outer white birch bark particles in the surface layers with coarse wood particles or wood fibres in the core layer. A factorial experiment used in a complete block design permitted to carry a suitable statistical analysis of measured properties. The two main considered factors were respectively the bark percentages in the surface layers with three levels and the type of material used in the core with two levels. Four replicates were done for each panel. The panels with wood particles in the core layer gave physical and mechanical properties satisfying the indoor requirements for particleboards and those with wood fibres in the core layer passed the requirement of medium fibres density board. Panel with 45% bark particles in the surface and 55% wood particles in the core was selected as the best because of its good dimensional stability
PROPERTIES OF BIRCH OUTER BARK PANELS REINFORCED WITH WOOD STRANDS IN THE SURFACE LAYERS
The high demand of wood as a raw material can be expected to soon lead to a severe shortage, resulting in drastic competition between various mills. This competition will be worsened by a restriction of forest cuttings in Quebec. One of the solutions to this problem would be to develop a mixed panel in which the strands of core layer are substituted by outer bark particles, and in this particular case, by particles of white birch. This type of panel could be used as siding panels and for the fabrication of boxes, bins, and commercial shelving. The objective of the present research work concerns the design, the manufacture, and the evaluation of mechanical and physical properties of this type of panel. Two manufacturing factors were taken into account: the strands orientation in the face layers and the alkali treatment made on the bark particles used in the core layer. All produced mixed panels met and exceeded almost all CAN3-0437 R-1 and O-1 property requirements. The alkali treatment of bark particles did not improve the mechanical properties of manufactured panels. The statistical analysis method that was used made it possible to choose the panel with non-oriented wood strands in the surface layers and alkali treated bark particles in the core layer as the best by taking into account only the bending strengths in both major and side axes of a panel
Propiedades fĂsicas y mecĂĄnicas de paneles a base de partĂculas de corteza externa de abeto blanco: Mezcla de paneles con partĂculas de madera versus fibra de madera
The use of outer white birch bark in canoes is an example of its oldest use by the first nations in Canada. This use confirms the hydrophobic characteristics of this bark, which can be capitalized on by using it in the outer layers of three-layer mixed composite panels in order to protect them from water infiltration from their surface. These panels were made up of outer white birch bark particles in the surface layers with coarse wood particles or wood fibres in the core layer. A factorial experiment used in a complete block design permitted to carry a suitable statistical analysis of measured properties. The two main considered factors were respectively the bark percentages in the surface layers with three levels and the type of material used in the core with two levels. Four replicates were done for each panel. The panels with wood particles in the core layer gave physical and mechanical properties satisfying the indoor requirements for particleboards and those with wood fibres in the core layer passed the requirement of medium fibres density board. Panel with 45% bark particles in the surface and 55% wood particles in the core was selected as the best because of its good dimensional stability.El uso de la corteza externa de abeto blanco en la fabricaciĂłn de canoas por las primeras naciones de CanadĂĄ es un ejemplo de su uso mĂĄs antiguo. Esto confirma sus caracterĂsticas hidrĂłfugas, la cual puede ser explotada mediante su uso en la superficie del panel compuesto de 3 capas para protegerlo de filtraciones de humedad. Estos tableros fueron fabricados con partĂculas de corteza externa en las capas superficiales, y con partĂculas gruesas o fibras de madera en el corazĂłn. Un experimento factorial en un diseño de bloque completo hizo posible realizar el diseño de experimento. Los dos grandes factores considerados, fueron el porcentaje de corteza en las capas superficiales con 3 niveles y el tipo de material usado en el corazĂłn, con dos niveles respectivamente (partĂculas y fibras de madera). Cuatro rĂ©plicas fueron hechas para cada panel. SĂłlo los tableros con partĂculas gruesas de madera en el corazĂłn pasaron todas las pruebas fĂsicas satisfaciendo los requerimientos del interior de los tableros de partĂculas. Paneles con 45% de partĂculas de corteza en la superficie y 55% de partĂculas de madera en el corazĂłn fueron seleccionados como los mejores, debido a su buena estabilidad dimensional
PHYSICAL AND MECHANICAL PROPERTIES OF PANEL BASED ON OUTER BARK PARTICLES OF WHITE BIRCH: MIXED PANELS WITH WOOD PARTICLES VERSUS WOOD FIBRES PROPIEDADES FĂSICAS Y MECĂNICAS DE PANELES A BASE DE PARTĂCULAS DE CORTEZA EXTERNA DE ABETO BLANCO: MEZCLA DE PANELES CON PARTĂCULAS DE MADERA VERSUS FIBRA DE MADERA
The use of outer white birch bark in canoes is an example of its oldest use by the first nations in Canada. This use confirms the hydrophobic characteristics of this bark, which can be capitalized on by using it in the outer layers of three-layer mixed composite panels in order to protect them from water infiltration from their surface. These panels were made up of outer white birch bark particles in the surface layers with coarse wood particles or wood fibres in the core layer. A factorial experiment used in a complete block design permitted to carry a suitable statistical analysis of measured properties. The two main considered factors were respectively the bark percentages in the surface layers with three levels and the type of material used in the core with two levels. Four replicates were done for each panel. The panels with wood particles in the core layer gave physical and mechanical properties satisfying the indoor requirements for particleboards and those with wood fibres in the core layer passed the requirement of medium fibres density board. Panel with 45% bark particles in the surface and 55% wood particles in the core was selected as the best because of its good dimensional stability.El uso de la corteza externa de abeto blanco en la fabricaciĂłn de canoas por las primeras naciones de CanadĂĄ es un ejemplo de su uso mĂĄs antiguo. Esto confirma sus caracterĂsticas hidrĂłfugas, la cual puede ser explotada mediante su uso en la superficie del panel compuesto de 3 capas para protegerlo de filtraciones de humedad. Estos tableros fueron fabricados con partĂculas de corteza externa en las capas superficiales, y con partĂculas gruesas o fibras de madera en el corazĂłn. Un experimento factorial en un diseño de bloque completo hizo posible realizar el diseño de experimento. Los dos grandes factores considerados, fueron el porcentaje de corteza en las capas superficiales con 3 niveles y el tipo de material usado en el corazĂłn, con dos niveles respectivamente (partĂculas y fibras de madera). Cuatro rĂ©plicas fueron hechas para cada panel. SĂłlo los tableros con partĂculas gruesas de madera en el corazĂłn pasaron todas las pruebas fĂsicas satisfaciendo los requerimientos del interior de los tableros de partĂculas. Paneles con 45% de partĂculas de corteza en la superficie y 55% de partĂculas de madera en el corazĂłn fueron seleccionados como los mejores, debido a su buena estabilidad dimensional
Properties of white birch (Betula papyrifera) outer bark particleboards with reinforcement of coarse wood particles in the core layer
This study proposes substituting traditional raw materials in the surface
layers of wood particleboards with the water resistant white birch (Betula papyrifera) outer
bark particles, which can help improve the dimensional stability of
manufactured mixed particleboards, thereby alleviating shortages of raw
material in a cost-efficient manner. Mixed particleboards were fabricated in the laboratory using untreated or
alkali treated white birch outer bark particles as substitute material.
These particles were resinated successively with three percentages of
phenol-formaldehyde resin. Overall, the results of this study clearly
demonstrate that the panels could be manufactured using up to 45% of
the proposed substitute material and still maintain the required mechanical
and physical properties. Alkali treatment was used to remove natural wax from bark particles
surface which hinders resin adhesion. This treatment negatively affected
mechanical and physical properties of finished panels and the variation of
phenol-formaldehyde resin percentage in the bark particles significantly
affected only their hardness. Panel with untreated bark particles in the surface layers, resinated with
5% phenol-formaldehyde resin was selected as the best with the help
of a statistical analysis carried out in a factorial complete block design,
especially from the dimensional stability criterion.Propriétés des panneaux d'écorce externe de bouleau blanc
(Betula papyrifera) avec renfort de particules grossiÚres de bois dans la couche médiane. L'objet de cette étude est de substituer la matiÚre premiÚre
traditionnelle dans les couches couvrantes des panneaux de particules
conventionnelles par les particules hydrophobes d'Ă©corce externe de
bouleau blanc (Betula papyrifera) qui peuvent aider à améliorer la stabilité
dimensionnelle des panneaux mixtes produits et ainsi permettre d'alléger
la pĂ©nurie de la matiĂšre premiĂšre d'une maniĂšre rentable. Les panneaux de particules mixtes ont Ă©tĂ© fabriquĂ©s Ă
l'Ă©chelle du laboratoire en utilisant les particules d'Ă©corce
externe de bouleau blanc non traitées ou traitées à la soude
comme matériel de substitution. Ces particules ont été
encollées successivement avec trois pourcentages de colle
phénol-formaldéhyde. Les résultats de cette étude
dĂ©montrent d'un bout Ă l'autre que les panneaux pourraient ĂȘtre
fabriqués en utilisant jusqu'à 45 % de matiÚre de
substitution proposée et maintenir toujours les exigences des
propriétés mécaniques et physiques. Le traitement à la soude a été utilisé afin d'enlever la
cire naturelle de la surface des Ă©corces qui empĂȘche l'adhĂ©sion
de la colle. Ce traitement a affecté négativement les
propriétés mécaniques et physiques des panneaux produits et la
variation du pourcentage de la colle phénol-formaldéhyde dans les
particules d'écorce a affecté leur dureté de maniÚre
hautement significative. Le panneau avec les particules d'écorce non traitées dans les
couches couvrantes et encollées avec 5 % de
phénol-formaldéhyde a été sélectionné comme le
meilleur Ă l'aide d'une analyse statistique faite dans un plan factoriel
en blocs complets, en se basant sur le critÚre de la stabilité
dimensionnelle