Reconstituted wood panels have several advantages in terms of ease of manufacturing,but their shorter life span results in a huge amount of reconstituted wood panels being discarded in sorting centers yearly.Currently...Reconstituted wood panels have several advantages in terms of ease of manufacturing,but their shorter life span results in a huge amount of reconstituted wood panels being discarded in sorting centers yearly.Currently,the most common approach for dealing with this waste is incineration.In this study,reconstituted wood panels were converted into activated biochar through a two-step thermochemical process:(i)biochar production using pilot scale fast pyrolysis at 250 kg/h and 450℃;and(ii)a physical activation at three temperatures(750℃,850℃ and 950℃)using an in-house activation furnace(1 kg/h).Results showed that the first stage removed about 66% of the nitrogen from the wood panels in the form of NO,NH3,and trimethylamine,which were detected in small amounts compared to emitted CO_(2).Compared to other types of thermochemical conversion methods(e.g.,slow pyrolysis),isocyanic acid and hydrogen cyanide were not detected in this study.The second stage produced activated biochar with a specific surface area of up to 865 m^(2)/g at 950℃.The volatile gases generated during activation were predominantly composed of toluene and benzene.This two-step process resulted in nitrogen-rich carbon in the form of pyrrolic and pyridinic nitrogen.Activated biochars were then evaluated for their SO_(2) retention performance and showed an excellent adsorption capacity of up to 2140 mg/g compared to 65 mg/g for a commercial activated carbon(889 m^(2)/g).End-of-life reconstituted wood panels and SO_(2) gas are problematic issues in Canada where the economy largely revolves around forestry and mining industries.展开更多
Soy-protein isolate(SPI)was used to prepare non-isocyanate polyurethane(NIPU)thermosetting adhesives for wood panels by reacting it with dimethyl carbonate(DMC)and hexamethylene diamine.Both linear as well as branched...Soy-protein isolate(SPI)was used to prepare non-isocyanate polyurethane(NIPU)thermosetting adhesives for wood panels by reacting it with dimethyl carbonate(DMC)and hexamethylene diamine.Both linear as well as branched oligomers were obtained and identified,indicating how such oligomer structures could further cross-link to form a hardened network.Unusual structures were observed,namely carbamic acid-derived urethane linkages coupled with lactam structures.The curing of the adhesive was followed by thermomechanical analysis(TMA).It appeared to follow a two stages process:First,at a lower temperature(maximum 130℃),the growth of linear oligomers occurred,finally forming a physically entangled network.This appeared to collapse and disentangle,causing a decrease of MOE,as the temperature increases.This appears to be due to the ever more marked Brownian movements of the linear oligomer chains with the increase of the temperature.Second,chemical cross-linking of the chains appeared to ensue,forming a hardened network.This was shown by the thermomechanical analysis(TMA)showing two distinct MOE maxima peaks,one around 130℃ and the other around 220℃,with a very marked MOE decrease between the two.Plywood panels were prepared and bonded with the SPI-NIPU wood adhesive and the results obtained are presented.The adhesive appeared to pass comfortably the requirements for dry strength of relevant standards,showing to be suitable for interior grade plywood panels.It did not pass the requirements for wet tests.However,addition of 15%of glycerol diglycidyl ether improved the wet tests results but still not enough to satisfy the standards requirements.展开更多
The reinforcing impact of Lignocellulosic micro and nanofibrillated cellulose(L-MNFCs)obtained from Eucalyp-tus Globulus bark in Urea-Formaldehyde UF adhesive was tested.L-MNFCs were prepared by an environmentally fri...The reinforcing impact of Lignocellulosic micro and nanofibrillated cellulose(L-MNFCs)obtained from Eucalyp-tus Globulus bark in Urea-Formaldehyde UF adhesive was tested.L-MNFCs were prepared by an environmentally friendly,low-cost process using a combination process involving steam explosion followed by refining and ultra-fine grinding.Obtained L-MNFCs showed a web-like morphology with some aggregates and lignin nanodroplets.They present a mixture of residual fibers and fine elements with a width varying between 5 nm to 20μm,respec-tively.The effects of the addition of low amounts of L-MNFCs(1%wt.)on the properties of three different adhe-sives(Urea-Formaldehyde UF,Phenol-Formaldehyde PF,and Tannin-Hexamine TH)were studied by the evolution of the pH,the viscosity,and the mechanical properties.Results showed that the viscosity of PF and UF adhesives increased with the addition of L-MNFCs,unlike TH.Meanwhile,the addition led to better mechan-ical behavior for the three adhesives.Particleboards were then prepared using modified UF with L-MNFCs and tested.Results showed that an amount of 1%wt.of L-MNFCs was sufficient to increase the internal bonding by≈67%,the modulus of elasticity by≈43%,and the modulus of rupture by≈29%.展开更多
Magnesite-bonded wood wool panel(MWWP)is an inorganic-bonded panel product in which wood excelsior is bonded with magnesite.Lowering the hygroscopicity is one of the key measures to improve the quality of the panel.In...Magnesite-bonded wood wool panel(MWWP)is an inorganic-bonded panel product in which wood excelsior is bonded with magnesite.Lowering the hygroscopicity is one of the key measures to improve the quality of the panel.In this study,moisture absorption mechanism of MWWP and measures generally applied to lower its hygroscopicity were reviewed.Three methods were then experimented to improve the dimensional stability of the panel,including adjusting the molar ratio of raw materials,adding additives and optimizing the conditioning process.The results showed that satisfying dimensional stability could be achieved when the molar ratio of MgO to MgCl_(2) was 5:1,the No.2 composite additive(aluminum powder+NH_(4)H_(2)PO_(4)+ferric alum)was adopted and a constant temperature and humidity treatment was applied in the first stage of conditioning.展开更多
This brief article reviews a very particular and quite narrowfield,namely what has been done and what is needed to know for tannin adhesives for wood panels to succeed industrially.The present fashionable focus on bio...This brief article reviews a very particular and quite narrowfield,namely what has been done and what is needed to know for tannin adhesives for wood panels to succeed industrially.The present fashionable focus on bioadhe-sives has led to producing chemical adhesive formulations and approaches for tannin adhesives as a subject of academic publications.These,as good and original they might be,are and will still remain a rather empty aca-demic exercise if not put to the test of real industrial trials and industrial use.They will remain so without the“little”secrets and techniques outlined here that show that there is a great gap between developing an adhesive formulation in the laboratory and the hard reality to make it work where it does really count,in its industrial application.It outlines the fact that even more modern and excellent,newly developed bioadhesive formulations might well miserably fail once tried in the industry if the problems that always arise in their upgrading are not identified and solved,and solved well.It also outlines the fact that not only must costs always be taken into account and that a practical and possibly easy-to-handle approach must always be used,but too expensive or complex and unyielding adhesive systems are also often shown to be unusable or unsuitable in industry.展开更多
基金funded by the Ministere de l’Economie,de la Science et de l’Innovation du Quebec,the Natural Sciences and Engineering Research Council of Canada(NSERC)the Consortium de recherche et innovations en bioprocedes industriels au Quebec(Cribiq)+1 种基金the Canada Research Chair Program,the College of Abitibi-Temiscaminguethe Industrial Waste Technology Centre(Centre Technologique des Residus Industriels)through its partner on this project,Airex Energy.
文摘Reconstituted wood panels have several advantages in terms of ease of manufacturing,but their shorter life span results in a huge amount of reconstituted wood panels being discarded in sorting centers yearly.Currently,the most common approach for dealing with this waste is incineration.In this study,reconstituted wood panels were converted into activated biochar through a two-step thermochemical process:(i)biochar production using pilot scale fast pyrolysis at 250 kg/h and 450℃;and(ii)a physical activation at three temperatures(750℃,850℃ and 950℃)using an in-house activation furnace(1 kg/h).Results showed that the first stage removed about 66% of the nitrogen from the wood panels in the form of NO,NH3,and trimethylamine,which were detected in small amounts compared to emitted CO_(2).Compared to other types of thermochemical conversion methods(e.g.,slow pyrolysis),isocyanic acid and hydrogen cyanide were not detected in this study.The second stage produced activated biochar with a specific surface area of up to 865 m^(2)/g at 950℃.The volatile gases generated during activation were predominantly composed of toluene and benzene.This two-step process resulted in nitrogen-rich carbon in the form of pyrrolic and pyridinic nitrogen.Activated biochars were then evaluated for their SO_(2) retention performance and showed an excellent adsorption capacity of up to 2140 mg/g compared to 65 mg/g for a commercial activated carbon(889 m^(2)/g).End-of-life reconstituted wood panels and SO_(2) gas are problematic issues in Canada where the economy largely revolves around forestry and mining industries.
文摘Soy-protein isolate(SPI)was used to prepare non-isocyanate polyurethane(NIPU)thermosetting adhesives for wood panels by reacting it with dimethyl carbonate(DMC)and hexamethylene diamine.Both linear as well as branched oligomers were obtained and identified,indicating how such oligomer structures could further cross-link to form a hardened network.Unusual structures were observed,namely carbamic acid-derived urethane linkages coupled with lactam structures.The curing of the adhesive was followed by thermomechanical analysis(TMA).It appeared to follow a two stages process:First,at a lower temperature(maximum 130℃),the growth of linear oligomers occurred,finally forming a physically entangled network.This appeared to collapse and disentangle,causing a decrease of MOE,as the temperature increases.This appears to be due to the ever more marked Brownian movements of the linear oligomer chains with the increase of the temperature.Second,chemical cross-linking of the chains appeared to ensue,forming a hardened network.This was shown by the thermomechanical analysis(TMA)showing two distinct MOE maxima peaks,one around 130℃ and the other around 220℃,with a very marked MOE decrease between the two.Plywood panels were prepared and bonded with the SPI-NIPU wood adhesive and the results obtained are presented.The adhesive appeared to pass comfortably the requirements for dry strength of relevant standards,showing to be suitable for interior grade plywood panels.It did not pass the requirements for wet tests.However,addition of 15%of glycerol diglycidyl ether improved the wet tests results but still not enough to satisfy the standards requirements.
基金The authors gratefully acknowledge the financial support of Labex Tec21 and Labex Arbre for the thesis funding.This work was also supported by the Franco-Chilean EcosSud Collaborative Program C18E05,ANID PIA/Apoyo CCTE AFB170007 of Universidad de Concepcion.
文摘The reinforcing impact of Lignocellulosic micro and nanofibrillated cellulose(L-MNFCs)obtained from Eucalyp-tus Globulus bark in Urea-Formaldehyde UF adhesive was tested.L-MNFCs were prepared by an environmentally friendly,low-cost process using a combination process involving steam explosion followed by refining and ultra-fine grinding.Obtained L-MNFCs showed a web-like morphology with some aggregates and lignin nanodroplets.They present a mixture of residual fibers and fine elements with a width varying between 5 nm to 20μm,respec-tively.The effects of the addition of low amounts of L-MNFCs(1%wt.)on the properties of three different adhe-sives(Urea-Formaldehyde UF,Phenol-Formaldehyde PF,and Tannin-Hexamine TH)were studied by the evolution of the pH,the viscosity,and the mechanical properties.Results showed that the viscosity of PF and UF adhesives increased with the addition of L-MNFCs,unlike TH.Meanwhile,the addition led to better mechan-ical behavior for the three adhesives.Particleboards were then prepared using modified UF with L-MNFCs and tested.Results showed that an amount of 1%wt.of L-MNFCs was sufficient to increase the internal bonding by≈67%,the modulus of elasticity by≈43%,and the modulus of rupture by≈29%.
基金This study is funded by National Natural Science Foundation(31070502)Public Farewell Project of National Forestry Bureau(201004006-6)support of the Priority Academic Program Development of Jiangsu Higher Education Institutions and Co-innovation Center of Efficient Processing and Utilization of Forest Resources,Nanjing Forestry University,Nanjing 210037,China.
文摘Magnesite-bonded wood wool panel(MWWP)is an inorganic-bonded panel product in which wood excelsior is bonded with magnesite.Lowering the hygroscopicity is one of the key measures to improve the quality of the panel.In this study,moisture absorption mechanism of MWWP and measures generally applied to lower its hygroscopicity were reviewed.Three methods were then experimented to improve the dimensional stability of the panel,including adjusting the molar ratio of raw materials,adding additives and optimizing the conditioning process.The results showed that satisfying dimensional stability could be achieved when the molar ratio of MgO to MgCl_(2) was 5:1,the No.2 composite additive(aluminum powder+NH_(4)H_(2)PO_(4)+ferric alum)was adopted and a constant temperature and humidity treatment was applied in the first stage of conditioning.
文摘This brief article reviews a very particular and quite narrowfield,namely what has been done and what is needed to know for tannin adhesives for wood panels to succeed industrially.The present fashionable focus on bioadhe-sives has led to producing chemical adhesive formulations and approaches for tannin adhesives as a subject of academic publications.These,as good and original they might be,are and will still remain a rather empty aca-demic exercise if not put to the test of real industrial trials and industrial use.They will remain so without the“little”secrets and techniques outlined here that show that there is a great gap between developing an adhesive formulation in the laboratory and the hard reality to make it work where it does really count,in its industrial application.It outlines the fact that even more modern and excellent,newly developed bioadhesive formulations might well miserably fail once tried in the industry if the problems that always arise in their upgrading are not identified and solved,and solved well.It also outlines the fact that not only must costs always be taken into account and that a practical and possibly easy-to-handle approach must always be used,but too expensive or complex and unyielding adhesive systems are also often shown to be unusable or unsuitable in industry.
