Pour savoir comment effectuer et gérer un dépôt de document, consultez le « Guide abrégé – Dépôt de documents » sur le site Web de la Bibliothèque. Pour toute question, écrivez à corpus@ulaval.ca.
 

Personne :
Landry, Véronic

En cours de chargement...
Photo de profil

Adresse électronique

Date de naissance

Projets de recherche

Structures organisationnelles

Fonction

Nom de famille

Landry

Prénom

Véronic

Affiliation

Université Laval. Département des sciences du bois et de la forêt

ISNI

ORCID

Identifiant Canadiana

ncf11852576

person.page.name

Résultats de recherche

Voici les éléments 1 - 5 sur 5
  • PublicationRestreint
    Chemical surface densification of hardwood through lateral monomer impregnation and in situ electron beam polymerization, Part II : effect of irradiation dose on hardness, wood chemistry and polymer conversion
    (Springer Science, 2022-03-21) Triquet, Juliette; Landry, Véronic; Blanchet, Pierre
    Surface chemical densification was recently introduced as a low cost and fast process to improve surface hardness of wood. The asymmetric density profile at the surface due to polymer filled cells was achieved through unilateral impregnation of monomers and their fast in situ polymerization under electron beam radiations. This study investigates the effect of electron beam dose on the newly developed material in order to optimize and increase the performances. Effect of doses from 25 to 125 kGy on wood and polymer in situ were investigated by FTIR spectroscopy, confocal Raman microscopy and GC–MS quantification of extracted residual monomers. Brinell hardness of irradiated controls decreased with increased dose while it remained unchanged for densified samples. The effect of 25 kGy on the irradiated wood controls was insignificant, but evidence of cellulose depolymerization and decrease of hydrogen bonds strength was found at higher dose through FTIR analysis. Raman investigation of the acrylate conversion in situ showed that most of the polymerization was achieved with 25 kGy. Residual monomers were still present in the wood samples up to 100 kGy. Thus, 25 kGy was sufficient to polymerize monomers in situ and increase Brinell hardness of densified wood while avoiding degradation of wood. However, 100 kGy was necessary to ensure highest conversion and no residual monomers. This study is opening perspectives on radiation effects on wood for optimal materials development.
  • PublicationRestreint
    Chemical surface densification of hardwood through lateral monomer impregnation and in situ electron beam polymerization, Part I : density profile and surface hardness of three hardwood species
    (SpringerLink, 2021-03-23) Triquet, Juliette; Landry, Véronic; Blanchet, Pierre
    Filling wood cells with polymeric materials offers great opportunities to improve wood strength. Some applications, such as flooring, may require densification on one side of the material only. Yellow birch (Betula alleghaniensis Britt.), sugar maple (Acer saccharum Marsh.) and red oak (Quercus rubra L.) were surface densified through lateral chemical impregnation of monomers under vacuum followed by in situ electron beam polymerization. Lateral impregnation led to low mean chemical retention of 4% for sugar maple, 11% for red oak and 12% for yellow birch. X-ray densitometry and microtomography revealed an asymmetric density profile comparable to mechanically surface densified wood due to polymer-filled vessels. Scanning electron microscopy images showed presence of polymer-filled fibers beneath the surface. Brinell hardness of all species increased significantly compared to untreated wood. Low chemical retention significantly improved hardness due to localized polymer beneath the surface. Density profile characteristics were extracted from densitometry curves and correlated to hardness. Deep monomer penetration was more favorable to hardness than high surface density peak.
  • PublicationAccès libre
    Parametric study of a yellow birch surface impregnation process
    (Springer, 2021-03-29) Frias de Albuquerque, Mariana; Triquet, Juliette; Bégin-Drolet, André; Landry, Véronic; Blanchet, Pierre
    Wood is a renewable resource that has been used as a material in appearance products for years. Despite its acceptable mechanical resistance, different modification processes were developed to enhance wood’s hardness and make it an even more durable material. Impregnating wood pores with monomers under vacuum-pressure cycle is a common method for that purpose. However, most implemented processes are long and mostly submerge wood into a monomer formulation (Bethell’s full-cell process). For that, they can be considered wasteful on the quantity of materials used, energy consumed and on process duration. The objective of this paper was to evaluate the parameters that influence the penetration of monomers into the tangential surface of Yellow birch (Betula alleghaniensis Brit.) samples. The analyzed factors were the monomer formulation’s viscosity, the surface temperature, the vacuum level applied to the process, the anatomy of samples, and the absorption time. After impregnation, the weight gain of the samples was calculated. Monomer penetration depth was calculated and visualized using density profiles and micro X-ray tomography imaging. Results showed that using a low viscosity monomer formulation allied to a certain level of vacuum and absorption time can considerably increase the impregnation into the wood.
  • PublicationAccès libre
    Hardness of chemically densified Yellow birch in relation to wood density, polymer content and polymer properties
    (de Gruyter, 2020-08-24) Triquet, Juliette; Landry, Véronic; Blanchet, Pierre
    Density of wood can be increased by filling its porous structure with polymers. Such densification processes aim to increase hardness of wood and are particularly interesting for flooring applications. This study aims to evaluate efficiency of different polymers for chemical densification based on the polymer properties. Yellow birch (Betula alleghaniensis Britt.) was chemically densified with seven monomer mixtures through acrylate monomer impregnation and electron beam in-situ polymerization. Chemical retention and polymer content of densified woods were recorded. Hardness of treated and untreated Yellow birch was measured and compared to hardness of Jatoba (Hymenaea courbaril L.). All densified woods showed higher or comparable hardness to Jatoba. Hardness of densified wood was analyzed in relation to initial density of wood and polymer content of the material using multivariable linear mixed models. Efficiency of polymers for chemical densification was evaluated through effect of polymer content on hardness with interaction coefficients. Polymer films corresponding to monomer impregnating mixtures were prepared through low energy electron beam and characterized by their glass transition temperature, micro hardness, indentation modulus and crosslinking density. Polymers showed statistically significantly different efficiencies and were separated in two main groups. Overall, polymer efficiency increased with increasing glass transition temperature of polyacrylates.
  • PublicationRestreint
    Technical properties improvement of engineered flooring through hardening by acrylate surface impregnation and in-situ electron beaum polymerization
    (Springer, 2022-06-11) Triquet, Juliette; Landry, Véronic; Blanchet, Pierre
    Engineered hardwood foors are taking more and more market shares but remain underused in non-residential buildings such as public, heavy trafc areas besides residential use. Because hardness is the most important property for wood flooring products, wood densifcation processes have gained a lot of interest. Chemical surface densifcation of wood through acrylate monomer impregnation and in-situ electron beam polymerization is a very attractive approach ofering fast production times, low and localized chemical loading and increased hardness. This study presents the transfer of experimental work to an industrial product and evaluates the potential benefts of this process to improve properties of engineered hardwood fooring products with three North American species. The hardwood top layer of engineered wood fooring planks were surface impregnated with acrylate monomers using the previously developed process under vacuum, and polymerized with 100 kGy of high energy electrons. After polymerization, planks were fnished with a UV-curable clear fnishing system. X-ray densitometry revealed the asymmetric density profle created by the surface densifcation. Properties such as Brinell hardness and coating adhesion strength were signifcantly improved compared to natural engineered wood fooring. Brinell hardness increased by 25% for red oak, 23% for sugar maple and 55% for yellow birch. Color change upon UV exposure and dimensional stability remained similar to untreated wood. This study demonstrates the feasibility and efciency of chemical surface densifcation for improved durability of engineered hardwood fooring.