9 research outputs found
Improvement of the durability of heat-treated wood against termites
Thermal modification is an attractive alternative to improve the decay durability and dimensional stability of wood. However, thermally modified wood is generally not resistant to termite attacks, limiting the field of application of such materials. One way to overcome this drawback is to combine thermal modification treatment with an additional treatment. One such treatment is the impregnation of a boron derivative associated with appropriate vinylic monomers, which takes advantage of the thermal treatment to polymerise these monomers for boron fixation. Using this strategy, we recently showed that an impregnation of borax (2 or 4% boric acid equivalent) dissolved in a 10% aqueous solution of polyglycerolmethacrylate followed by thermal treatment under nitrogen at 220°C protects wood from both termite and decay degradations, even after leaching. Additionally, wood samples treated with a 10% polyglycerolmethacrylate aqueous solution and subjected to thermal treatment at 220°C presented improved resistance to termites while avoiding boron utilization. Based on these results, we investigate the effect of impregnation with two types of vinylic monomers, which are already used in the presence of boron, followed by thermal treatments at different temperatures. We evaluate termite and decay durability of wood to evaluate if thermal modification associated with light chemical modification could be a solution for utilization of thermally modified materials in termite-infested areas
Développement de nouvelles méthodes de préservation du bois basées sur l'utilisation combinée d'un traitement thermique et de borax
Environmental pressures appeared in France and in Europe in the last decades have substantially changed the methods for wood protection. In this context the Biocidal Products Regulations and the Biocidal Products Directive lead to the development of more environmentally friendly preservation methods and the growing interest in non-biocidal alternatives such as thermal treatment or chemical modification. Wood heat treatment at temperatures of 180 to 220 °C leads to the chemical modification of wood cell wall polymers conferring new properties to the material like its increased decay resistance and high dimensional stability. Despite these improvements, the durability of wood heat treatment is not sufficient to envisage use class 3 and 4 applications; where the wood is in contact with soil or termites. Moreover, Boron compounds present fungicidal and termiticidal properties. However, boron compounds have the drawback of being very easily leached out from wood making it unusable for applications in outdoor conditions. Wood chemical modification carried by the impregnation of aqueous solutions (10 %) of maleic anhydride polyglycerol adduct or polyglycerol methacrylates or phenol-formaldehyde resin, with or without borax followed by heat treatment at 220°C has shown some improvement of thermally modified wood properties particularly its resistance to termites in case of leach or notLes pressions environnementales apparues en France et en Europe au cours des derniĂšres dĂ©cennies ont considĂ©rablement changĂ© les mĂ©thodes de protection du bois. Dans ce contexte, le rĂšglement relatif aux produits biocides et la directive relative aux produits biocides conduisent au dĂ©veloppement de mĂ©thodes de prĂ©servation plus soucieuses de l'environnement et Ă lâintĂ©rĂȘt croissant pour des alternatives non biocides comme le traitement thermique ou la modification chimique. Le traitement thermique Ă des tempĂ©ratures de 180 Ă 220°C conduit Ă la modification chimique de la structure des diffĂ©rents constituants pariĂ©taux du bois en lui confĂ©rant de nouvelles propriĂ©tĂ©s comme une meilleure rĂ©sistance aux champignons basidiomycĂštes et une grande stabilitĂ© dimensionnelle. MalgrĂ© ces amĂ©liorations, la durabilitĂ© confĂ©rĂ©e au bois traitĂ© thermiquement demeure insuffisante pour des applications en classes 3 ou 4 dans lesquelles le bois est en contact avec le sol ou est en prĂ©sence de termites. Par ailleurs, le bore sous forme dâacide borique ou de borax prĂ©sente des propriĂ©tĂ©s fongicides et termiticides. Cependant, les produits Ă base de bore prĂ©sentent l'inconvĂ©nient d'ĂȘtre trĂšs facilement lessivables les rendant inutilisables pour des applications en conditions extĂ©rieures. Les modifications chimiques rĂ©alisĂ©es suite Ă l'imprĂ©gnation de solutions Ă 10% d'anhydride malĂ©ique de polyglycĂ©rol ou de mĂ©thacrylates de polyglycĂ©rol ou de rĂ©sine phĂ©nol formaldĂ©hyde avec ou sans borax avant le traitement thermique ont apportĂ© une amĂ©lioration des propriĂ©tĂ©s des bois modifiĂ©s thermiquement et surtout une rĂ©sistance aux termites avec ou sans lessivag
Development of new wood treatments combining boron impregnation and thermo-modification
Les pressions environnementales apparues en France et en Europe au cours des derniĂšres dĂ©cennies ont considĂ©rablement changĂ© les mĂ©thodes de protection du bois. Dans ce contexte, le rĂšglement relatif aux produits biocides et la directive relative aux produits biocides conduisent au dĂ©veloppement de mĂ©thodes de prĂ©servation plus soucieuses de l'environnement et Ă lâintĂ©rĂȘt croissant pour des alternatives non biocides comme le traitement thermique ou la modification chimique. Le traitement thermique Ă des tempĂ©ratures de 180 Ă 220°C conduit Ă la modification chimique de la structure des diffĂ©rents constituants pariĂ©taux du bois en lui confĂ©rant de nouvelles propriĂ©tĂ©s comme une meilleure rĂ©sistance aux champignons basidiomycĂštes et une grande stabilitĂ© dimensionnelle. MalgrĂ© ces amĂ©liorations, la durabilitĂ© confĂ©rĂ©e au bois traitĂ© thermiquement demeure insuffisante pour des applications en classes 3 ou 4 dans lesquelles le bois est en contact avec le sol ou est en prĂ©sence de termites. Par ailleurs, le bore sous forme dâacide borique ou de borax prĂ©sente des propriĂ©tĂ©s fongicides et termiticides. Cependant, les produits Ă base de bore prĂ©sentent l'inconvĂ©nient d'ĂȘtre trĂšs facilement lessivables les rendant inutilisables pour des applications en conditions extĂ©rieures. Les modifications chimiques rĂ©alisĂ©es suite Ă l'imprĂ©gnation de solutions Ă 10% d'anhydride malĂ©ique de polyglycĂ©rol ou de mĂ©thacrylates de polyglycĂ©rol ou de rĂ©sine phĂ©nol formaldĂ©hyde avec ou sans borax avant le traitement thermique ont apportĂ© une amĂ©lioration des propriĂ©tĂ©s des bois modifiĂ©s thermiquement et surtout une rĂ©sistance aux termites avec ou sans lessivageEnvironmental pressures appeared in France and in Europe in the last decades have substantially changed the methods for wood protection. In this context the Biocidal Products Regulations and the Biocidal Products Directive lead to the development of more environmentally friendly preservation methods and the growing interest in non-biocidal alternatives such as thermal treatment or chemical modification. Wood heat treatment at temperatures of 180 to 220 °C leads to the chemical modification of wood cell wall polymers conferring new properties to the material like its increased decay resistance and high dimensional stability. Despite these improvements, the durability of wood heat treatment is not sufficient to envisage use class 3 and 4 applications; where the wood is in contact with soil or termites. Moreover, Boron compounds present fungicidal and termiticidal properties. However, boron compounds have the drawback of being very easily leached out from wood making it unusable for applications in outdoor conditions. Wood chemical modification carried by the impregnation of aqueous solutions (10 %) of maleic anhydride polyglycerol adduct or polyglycerol methacrylates or phenol-formaldehyde resin, with or without borax followed by heat treatment at 220°C has shown some improvement of thermally modified wood properties particularly its resistance to termites in case of leach or no
Improvement of wood decay and termite durability resulting from combined treatments based on borax/phenol-formaldehyde impregnation followed by thermal modification
International audienc
Decay and termite resistance of pine blocks impregnated with different additives and subjected to heat treatment
International audienc
Nouveaux traitements de préservation du bois associant bore, méthacrylate de polyglycérol et traitement thermique
International audienc