Donatien Pascal Kamdem

Durability of heat-treated wood

G. trabeum and 46% for P. placenta. About 56% and 54% weight loss were obtained for southern pine control exposed to G. trabeum and P. placenta, respectively. The weight loss of the water and acetone extracted heat-treated sample exposed to P. placenta was 49.7% and 53.9%, respectively. Only about 11% and 14.8% weight loss was obtained for water and acetone extracted samples exposed to G. trabeum. The moisture content of the tested samples was about 70 ± 10% for the un-heated controls and 50 ± 10% for heat-treated samples. This treatment may modify the durability from non-resistant to moderate/resistant species depending on the fungus species as defined in the ASTM 2017 standard. The data from the bending test indicate that such treatment may create a 10 to 50% reduction in MOR and deflection, which will limit the use of such wood for structural purposes.G. trabeum 11%, durch P. placenta 46%. Bei Kiefernproben waren es sogar 56% bzw. 54%. Die Gewichtsverluste von mit Wasser bzw. Aceton extrahierten und dann hitzebehandelten Proben betrugen gegenüber P. placenta 49,7 bzw. 53,9%. Die Werte gegenüber G. trabeum lagen dagegen nur bei 11% und 14,8%. Die Feuchte der geprüften hitzebehandelten Proben betrug 70 ± 10%, die der nicht erhitzten Proben 50 ± 10%. Die Hitzebehandlung könnte also die Dauerhaftigkeit von Holzproben von einer nicht widerstandfähigen zu einer mäßig widerstandsfähigen modifizieren, abhängig von der Pilzart gemäß ASTM 2017. Die Prüfung der Biegefestigkeiten ergab, daß die Hitzebehandlung einen Rückgang des MOR und der Durchbiegung um 10–50% verursachen kann, wodurch die Verwendung solcher Proben als Bauholz eingeschränkt ist.

Heat-treated timber: potentially toxic byproducts presence and extent of wood cell wall degradation

13C NMR to determine which type of loose chemical compounds were produced by the thermal treatment. The formation of some toxic polynuclear aromatic hydrocarbons derivatives of phenantrene as well as other classes of polyaromatics compounds was detected. It is most likely that the presence of all such compounds contributes, perhaps to a relatively substantial extent, to the reported resistance of heat treated timber to fungal and other biological attack. Other allegedly non-toxic compounds due to wood constituents degradation were also found, mainly the by-products of lignin pyrolysis. The extent of toxic and non-toxic compounds in the heat treated wood were not quantified, but it can be stated that their proportion appears to be quite small. The lack of quantification of the concentration of these products does not allow to ascertain if the final product is toxic or not, and to what extent. Nonetheless, the amount of polynuclear aromatic hydrocarbon-type derivatives should be quantified and related to the type of heat treatment process undertaken before assigning to this type of wood treatment a completely clean health safety label.13C NMR untersucht. Einige toxische polykondensierte Aromaten vom Phenantrentyp und andere Polyaromaten wurden gefunden. Es ist möglich, daß diese zur bekannten Widerstandsfähigkeit des hitzebhandelten Holzes gegen Pilze und andere Mikroorganismen beitragen. Gefunden wurden auch andere, vorgeblich nicht-toxische Aubbauprodukte der Holzkomponenten, insbesondere aufgrund der Ligninpyrolyse. Die Substanzen wurden nicht quantitativ bestimmt; ihr Anteil ist jedoch sehr gering. Daraus kann man allerdings nicht schließen, ob diese Produkte tatsächlich toxisch sind oder nicht. Denn dazu müßten diese Abbauprodukte quantifiziert werden und den verschiedenen Methoden der Hitzebehandlung zugeordnet werden, bevor ein Gesundheitsrisiko ausgeschlossen werden kann.

Study of industrial boiling process on walnut colour: Experimental study under industrial conditions

Juglans regia) logs, measured during boiling water process under industrial conditions. The colour changes in sapwood and heartwood evolution were analysed according to the previous results obtained in laboratory. As it was expected, the sapwood color changes quickly during the first 10 hours and definitely after 30 hours of industrial treatment. Its colour is darker and redder. Heartwood behavior is quite different because its colour is changing slowly during the first 10 hours and important changes are occuring after the 39 first hours. These mean results were obtained on the four logs studied. This work precise the particular behavior of the color of wood during boiling and the efficient method used. This study may be used by industries, which are concerned by heating treatment before slicing, and applied to other species.Juglans regia), die während der Behandlung in kochendem Wasser bei Industriebedingungen entstehen. Die Verfärbungen im Splint- und Kernholz wurden analysiert unter Verwendung früherer Ergebnisse aus Laboruntersuchungen. Wie erwartet erfolgt die Verfärbung im Splintholz rasch während der ersten 10 Stunden. Nach 30 Stunden wird ein Endwert erreicht. Die farbe wird dunkler und rötlicher. Die Farbänderungen im Kernholz verlaufen ander; sie beginnen sehr langsam während der ersten 10 Stunden und deutliche Farbänderungen finden erst nach 39stündigem Kochen statt Die Ergebnisse werden als Mittel aus vier Rundhölzern genommen. Sie präzisieren die spezielle Verfärbungwährend des Kochens. Die verwendete Methode erwies sich als effektiv. Die Untersuchung könnte verwendet werden in Industrieprozessen, in welchen Erhitzen oder Dämpfen vor der Auftrennung des Holzes eingesetzt wird. Die Ergebnisse können auch auf andere Holzartn übertragen werden.

Natural decay resistance of LVL made of veneers from durable and non-durable wood species

Laminated veneer lumber (LVL) was laboratory manufactured using veneers from decay and non decay resistant species in order to evaluate changes in the durability as a result of the LVL manufacturing process, and to test if the mixing of decay resistant species and non decay resistant species can improve durability. Laboratory soil block test and field test were conducted. The durability of solid wood was comparable to that of LVL made using the same species. For LVL made using veneer from durable and non-durable wood species, durability was improved when two faces and one core veneers were from decay resistant species.ZusammenfassungAus fäulnisunbeständigen und -beständigen Holzarten wurde in einem Labor Brettschichtholz hergestellt, um Veränderungen in der Dauerhaftigkeit auf Grund ihres Herstellungsverfahrens zu evaluieren, und um zu prüfen, ob das Mischen von fäulnisunbeständigem mit fäulnisbeständigen Holzarten die Dauerhaftigkeit von LVL verbessern kann. Bodentests wurden im Labor und als Freilandversuche durchgeführt. Bei Verwendung derselben Spezies war die Dauerhaftigkeit von massivem Holz vergleichbar mit derjenigen von LVL. Bei Brettschichtholz, welches aus resistenten und nicht resistenten Arten gefertigt war, wurde die Dauerhaftigkeit verbessert, wenn zwei Aussenschichten und eine Innenschicht aus einer fäulnisbeständigen Holzart war.

Efficacy of water-borne emulsion of copper naphthenate as preservative for northern red oak (Quercus rubra) and soft maple (Acer rubrum)

Northern red oak (Quercus rubra) and red maple (Acer rubrum) cubes pressure treated with water brone formulation of copper naphthenate were evaluated for resistance to attack by brown fungiGloeophylleum trabeum (Pers. Ex Fr.) Murr. (Madison 617 ATCC 11539) andPoria placenta (Fr.) Cooke (Madison 698, ATCC 11538), white rot fungiTrametes versicolor (L. Ex FR.) Pilat (R-105 from Jeff Morrell),Irpex lacteus Fries (FP-105915 from Jeff Morrell) andPleurotus ostreatus (Jacq. Ex Fr.) Kummer (ATCC 32237), and soft rot fungiChaetomium globosum (ATCC 34152) andPhialophoria Sp. Wood samples measuring 19 by 19 by 19 mm were pressure treated to target copper retentions of 12.48 kg/m3 (0.78 pcf), 9.77 kg/m3 (0.61 pcf), 5.6 kg/m3 (0.35 pcf), 4.5 kg/m3 (0.30 pcf), 2.56 kg/m3 (0.16 pcf), 1.2 kg/m3 (0.075 pcf), 0.48 kg/m3 (0.03 pcf). Data from laboratory soil block tests indicate that at 2.0 ± 0.5 kg/m3 (0.13 pcf) copper retention from water borne copper naphthenate, the protection is similar to that from a 1.6 kg/m3 (0.10 pcf) elemental copper from oil borne copper nathenate or 7.2 kg/m3 (0.45 pcf) total oxide from CCA-C. Higher copper levels (3.0 ± 0.2 kg/m3) are needed to protect against copper tolerant brown rot fungusP. placenta. Results from an American Wood Preserver’s Association standard leaching test indicate that waterborne copper naphthenate treated samples retained 80 to 90% the copper initially absorbed. The amount of leached copper increases with the pH of the leaching solution.ZusammenfassungEichen- und Ahornholz wurde unter Druck mit wässrigem Kupfernaphthenat imprägniert. Die Schutzwirkung gegenüber Braunfäule, Weißfäule und Moderfäule wurde mit folgenden Organismen geprüft:Gloephyllum trabeum, Poria placente, Trametes versicolor, Irpex lacteus, Pleurotus ostreatus, Chaetomium globosum undPhialophoria species. Holzproben der Abmessung 19 × 19 × 19 mm wurden unter Druck bis zu verschiedenen Kupferkonzentrationen zwischen 0,48 und 12,48 kg/m3 imprägniert. Mit der wässirgen Emulsion wurden bei einer Kupferkonzentration von 2 kg/m3 ähnliche Schutzwirkungen erzielt wie mit 1,6 kg/m3 auf Ölbasis oder 7,2 kg/m3 Gesamtoxid bei CCA-C-Schutzmitteln. Im Falle des BraunfäulepilzesP. placenta war eine höhere Kupferkonzentration (um 3 kg/m3) nötig. Nach Standard-Auswaschtests zeigte sich, daß die Proben 80 bis 90% der ursprünglich eingebrachten Kupfermenge zurückhielten. Die Menge des ausgelösten Kupfers steigt mit dem pH-Wert der Waschlösung.

Wood products and wood protection in China.

8 m3 in 2010 (Guan 1997). The forestry coverage in China is limited, and wood deterioration, caused by animals, insects, microorganisms, climate and other environmental circumstances decrease the durability of wood. The study of wood protection in China is called for to find ways and means to increase the service life of wood in use and therefore decrease the pressure on the wood fiber demand.8 m3 ansteigen wird (Guan 1997). Die Waldbedeckung von China ist allerdings begrenzt, und Holzschäden durch Tiere, Insekten, Mikroorganismen, Klima und Umweltfaktoren beeinträchtigen die Lebensdauer des Holzes. Der Holzschutz in China ist aufgerufen, Wege und Mittel zu finden, um die Lebensdauer von Holzprodukten zu erhöhen und so den Druck auf den Holzmarkt zu verringern.

Fiber yield for fully bleached kraft pulps from black locust (Robinia pseudoacacia) and silver maple (Acer saccharinum)

Robinia pseudoacacia) and silver maple (Acer saccharinum) with emphasis being placed on fiber yield. Black locust had longer fibers, a higher Seifert cellulose content, and a lower lignin content compared to the maple. The results were higher strength and bleached pulp yield for the black locust. The final yields were 49.5% for black locust and 47.7% for maple. These values are significantly higher than the 40–42% that is normally obtained for bleached softwood kraft pulps.

Biological performance of a formulation containing water-dispersible copper naphthenate and sodium fluoride against decay fungi

ABSTRACT Two formulations of wood preservative one containing water-dispersible copper naphthenate (CuN) alone and in combination with sodium fluoride (NaF) were used to treat southern pine sapwood blocks to determine the effect of the addition of sodium fluoride in the QNS on the protection against wood decay fungi using laboratory soil block tests following AWPA (American Wood protection Association) standard E10-16 [American Wood Protection Association AWPA-E10. (2016) Laboratory Method for Evaluating the Decay Resistance of Wood-based Materials Against Pure Basidiomycete Cultures: Soil/Block Test]. The standard consists in exposing treated blocks to pure monoculture of white rot (Irpex lacteus (FP-105915) and Trametes versicolor (R-105)) and brown rot fungi (Gloeophyllum trabeum (Madison 617) and Postia placenta (Madison 698) during a specific period. The weight loss (WL) in percentage of treated blocks was used as an indicator of the biological performance of treated blocks against basidiomycetes at specific retentions. Minimum WL was obtained with blocks treated with the formulation containing mixture of QNS and sodium fluoride with the retention of 0.29 kg/m3 Cu and 0.51 kg/m3 of fluorine in treated blocks. A copper retention of 1.65 kg/m3 from blocks treated with formulations containing only QNS was needed to obtain similar WL to blocks containing blocks Cu++ and F− (fluorine). The lower Cu retention is attributed to a combination of the presence of the fluorine with some toxic activities against bacteria and decay and the interaction of anions fluorine and ionic Cu (II) in the aqueous treating solutions to form more soluble biological toxic hydrate of copper fluoride ((H2O Cu (II) F2) in treated blocks compared to copper complexes less biological available in water-dispersible CuN-treated bocks.

Properties of red maple laminated veneer lumber impregnated with waterborne micronized and two soluble copper formulations

ABSTRACT Certain important quality parameters of red maple (Acer rubrum) laminated veneer lumber (LVL) impregnated with three waterborne formulations: copper azole (CA-B), micronized copper azole (MicroCA or MCA) and alkaline copper quaternary (ACQ-D) bonded with phenol formaldehyde or cross-linked polyvinyl acetate (XPVAc) adhesives were evaluated. Pre-dipping of veneers before LVL production and two post-manufacturing procedures, viz., vacuum-pressure and post-dipping of LVL, were applied. Maximum copper retention in pre-dip-treated, vacuum-pressure and post-dip-treated LVL was 1.4, 9.7 and 1.7 kg/m3, respectively. Copper retention in MCA-treated LVL was relatively lower than soluble formulations. Various physical, mechanical and bonding properties of treated LVL such as density, water absorption, swelling, flexural properties, hardness, tensile shear strength, delamination and wood failure (%) were studied and compared with untreated LVL. Little to negligible deleterious effect was observed on properties of LVL due to these chemical treatments. Analysis of variance results showed that most of properties of red maple LVL were not significantly different compared with those of untreated LVL. Therefore, vacuum-pressure impregnation process can be used to treat the red maple LVL with novel micronized copper formulations for increasing the service life of such products against biodegradation without affecting techno-mechanical quality parameters.