Effect of short-chain silicones bearing different functional groups on the resistance of pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.) against decay fungi

Abstract Blocks of pine sapwood and beech wood were treated with water-based emulsions containing short-chain silicones with different α-ω-bonded functional groups, such as diamino, carboxyl and carbonyl, betain, and epoxy groups. The weight percent gain upon treatment of the pine wood specimens was relatively high (10%–20%), but their cross-sectional bulking was low (1%–2.5%). Thus, the anti-shrink efficiency (ASE) due to the treatment was also low. The first water-submersion tests revealed some hydrophobation of the treated wood. A second submersion test, however, revealed successful hydrophobation only for betain-functionalised material. The carboxylated silicone even increased the speed of water uptake as compared to the controls. The samples treated with silicones bearing epoxy, diamino, and carboxy functionalities showed a distinct reduction in mass loss compared to the control samples after 16 weeks of incubation with the fungi Coniophora puteana and Trametes versicolor according to EN 113 and CEN/TS 15083-1, whereas the betain-functionalised silicone did not enhance fungal resistance. All silicones tested lowered the mass loss in a soft rot test according to ENv 807. The mode of action of the silicones is discussed.

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The fungal resistance of wood modified with glutaraldehyde

Holzforschung ◽

10.1515/hf.2011.138 ◽

2012 ◽

Vol 66 (2) ◽

Cited By ~ 7

Author(s):

Zefang Xiao ◽

Yanjun Xie ◽

Carsten Mai

Keyword(s):

Scots Pine ◽

Beech Wood ◽

Weight Percent Gain ◽

Brown Rot ◽

European Beech ◽

Soft Rot ◽

Weight Percent ◽

Fungal Resistance ◽

White Rot ◽

White Rot Fungus

Abstract Scots pine sapwood (Pinus sylvestris L.) and European beech wood (Fagus sylvatica L.) were treated with glutaraldehyde (GA) in aqueous solution in the presence of magnesium chloride as a catalyst to evaluate the durability improvement towards staining and rot fungi. The GA modified specimens were dipped in a spore suspension of the blue stain fungus Aureobasidium pullulans and incubated for 8 weeks. The growth on both pine and beech wood was restrained, when the weight percent gain (WPG) of the specimens was above 7%. Under this condition, GA-modified beech wood did not suffer any mass loss after incubation with the white rot fungus Trametes versicolor. The threshold to prevent decay of beech and pine specimens towards the brown rot fungus Coniophora puteana was at a WPG of only 3%. GA treatment to a WPG over 6% protected the Scots pine stakes from soft rot decay during 32 weeks’ exposure according to ENv 807 (2001).

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Treatment of wood with silica sols against attack by wood-decaying fungi and blue stain

Holzforschung ◽

10.1515/hf-2012-0133 ◽

2013 ◽

Vol 67 (6) ◽

pp. 697-705 ◽

Cited By ~ 12

Author(s):

Malte Pries ◽

Carsten Mai

Keyword(s):

Beech Wood ◽

Wood Decay ◽

Weight Percent Gain ◽

Weight Percent ◽

Silica Sol ◽

Blue Staining ◽

Water Leaching ◽

Decay Fungi ◽

Wood Decay Fungi ◽

Silica Sols

Abstract Pine sapwood was treated with various types of silica sols. Whereas alkaline sols were not able to penetrate deeper into wood, neutral and acidic sols showed good penetration. The weight percent gain of treated specimens amounted to 20–25%; bulking was negligible or even slightly negative. All silica sols in the treated specimens were stable against water leaching. A water submersion test revealed hydrophobation of the wood only after treatment with a cationic silica sol; all other silica sols increased the rate of water uptake. The addition of 2% cationic sol to a malt-agar growth medium caused growth inhibition of 40–50% of the wood decay fungi Coniophora puteana and Trametes versicolor, whereas the other silica sols did not inhibit growth. Pine sapwood and beech wood blocks treated with the cationic sol showed a strong reduction in mass loss compared to the control samples after incubation with C. puteana (pine) and T. versicolor (beech) according to EN 113 and CEN/TS 15083-1; all other silica sols did not inhibit fungal decay. The cationic silica sol reduced blue staining by Aureobasidium pullulans compared to the untreated control but did not fully prevent it; all other silica sols did not inhibit blue staining.

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Fabrication of highly stable and durable furfurylated wood materials. Part I: process optimization

Holzforschung ◽

10.1515/hf-2019-0286 ◽

2020 ◽

Vol 74 (12) ◽

pp. 1135-1146

Author(s):

Wanju Li ◽

Minghui Liu ◽

Hankun Wang ◽

Yan Yu

Keyword(s):

Orthogonal Experiment ◽

Weight Percent Gain ◽

Weight Percent ◽

Chinese Fir ◽

Curing Temperature ◽

Modulus Of Rupture ◽

Scale Production ◽

Range Analysis ◽

Decay Fungi ◽

Mold Resistance

AbstractIn order to improve dimensional stability and durability of wood, furfurylation of poplar and Chinese fir wood using newly developed furfuryl alcohol (FA) formulation combined with a common vacuum and pressure impregnation process was studied. An orthogonal experiment was designed to optimize the furfurylation process for the two wood species. The weight percent gain (WPG), equilibrium moisture content (EMC), anti-swelling efficiency (ASE), modulus of rupture (MOR), modulus of elasticity (MOE), as well as resistance to mold, decay fungi, and termites were evaluated. The results showed that nearly all the properties of the furfurylated wood could be improved to various extents. The average ASE of the furfurylated Chinese fir and poplar could reach as high as 80, 71, 92% and 79, 90, 75% in tangential and radial directions, and by volume, respectively, higher than most previously reported wood modification processes. Furthermore, the modified wood had excellent biological durability, with nearly 100% mold resistance, strong decay and termite resistance. Finally, processing parameters with 50% FA, 105–115 °C curing temperature, and 5–8 h curing time were therefore recommended for pilot-scale production of furfurylated poplar and Chinese fir wood based on range analysis.

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Effects of Wood Moisture Content and the Level of Acetylation on Brown Rot Decay

Forests ◽

10.3390/f11030299 ◽

2020 ◽

Vol 11 (3) ◽

pp. 299 ◽

Cited By ~ 4

Author(s):

Samuel L. Zelinka ◽

Grant T. Kirker ◽

Amy B. Bishell ◽

Samuel V. Glass

Keyword(s):

Moisture Content ◽

Mass Loss ◽

Linear Trend ◽

Fungal Growth ◽

Weight Percent Gain ◽

Brown Rot ◽

Weight Percent ◽

Wood Moisture Content ◽

Wood Moisture ◽

Brown Rot Decay

Acetylation is one of the most common types of wood modification and is commercially available throughout the world. Many studies have shown that acetylated wood is decay resistant at high levels of acetylation. Despite its widespread use, the mechanism by which acetylation prevents decay is still not fully understood. It is well known that at a given water activity, acetylation reduces the equilibrium moisture content of the wood cell wall. Furthermore, linear relationships have been found between the acetylation weight percent gain (WPG), wood moisture content, and the amount of mass loss in decay tests. This paper examines the relationships between wood moisture content and fungal growth in wood, with various levels of acetylation, by modifying the soil moisture content of standard soil block tests. The goal of the research is to determine if the reduction in fungal decay of acetylated wood is solely due to the reduction in moisture content or if there are additional antifungal effects of this chemical treatment. While a linear trend was observed between moisture content and mass loss caused by decay, it was not possible to separate out the effect of acetylation from fungal moisture generation. The data show significant deviations from previously proposed models for fungal moisture generation and suggest that these models cannot account for active moisture transport by the fungus. The study helps to advance our understanding of the role of moisture in the brown rot decay of modified wood.

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Acetylation of Wood Flour from Four Wood Species Grown in Nigeria Using Vinegar and Acetic Anhydride

International Journal of Carbohydrate Chemistry ◽

10.1155/2013/141034 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 7

Author(s):

Yakubu Azeh ◽

Gabriel Ademola Olatunji ◽

Cheku Mohammed ◽

Paul Andrew Mamza

Keyword(s):

Acetic Anhydride ◽

Wood Species ◽

Wood Flour ◽

Beech Wood ◽

Weight Percent Gain ◽

Weight Percent ◽

Adansonia Digitata ◽

Lignocellulosic Fibers ◽

Ft Ir ◽

African Locust Bean

Effect of acetylation on pretreated wood flour of four different wood species, Boabab (Adansonia digitata), Mahoganny (Daniella oliveri), African locust bean (Parkia biglobosa) and Beech wood (Gmelina arborea), had been investigated. The first batch of wood species were acetylated using acetic anhydride while the second batch were acetylated with commercial vinegar. Both experiments were conducted in the presence of varying amount of CaCl2 as catalyst and at temperature of 120°C for 3 h. The success of acetylation was determined based on Weight Percent Gain for each sample treated with either chemicals used. FT-IR, a veritable tool was used for the analysis of both treated and untreated samples to further investigate the success of acetylation. The results showed the presence of important band such as carbonyl absorptions at 1743, 1744, 1746, 1731, 1718 and 1696 cm−1 as appeared separately in the spectra of acetylated samples, confirming esterification occurred. The purpose of this work was to investigate the applicability of vinegar for acetylation of lignocellulosic fibers. Blends/composites were prepared by solution casting and their kinetics investigated in distilled water. The results indicated they could be used in outdoor applications such as, decking and packaging.

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Beech wood treated with polyglycerol succinate: a new effective method for its protection and stabilization

Holzforschung ◽

10.1515/hf-2019-0060 ◽

2020 ◽

Vol 74 (4) ◽

pp. 351-361 ◽

Cited By ~ 4

Author(s):

Clément L’Hostis ◽

Emmanuel Fredon ◽

Marie-France Thévenon ◽

Francisco-José Santiago-Medina ◽

Philippe Gérardin

Keyword(s):

Beech Wood ◽

Treated Wood ◽

Weight Percent ◽

Decay Resistance ◽

Curing Temperature ◽

Ionization Time ◽

Chemical Structures ◽

Treatment Conditions ◽

Middle Infrared

AbstractThis paper deals with an original and non-biocidal chemical treatment consisting of a vacuum/pressure impregnation step of beech wood with a water-borne mixture made from heat-activated condensation of succinic anhydride (SA) and glycerol (G). Chemical structures of adducts were established using matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF) investigations. Beech wood was impregnated and cured in order to induce in situ polymerization of glycerol/succinic adducts (GSA) in the cell walls, leading to the formation of polyglycerol succinate (PGS) polyester. Various treatment conditions were investigated depending on the duration (6–72 h) and curing temperature (103–160°C). Weight percent gains (WPGs) ranging between 40 and 60% were obtained. Attenuated total reflectance-middle infrared spectroscopy (ATR-MIR) and carbon-13 nuclear magnetic resonance (13C-NMR) spectroscopy confirmed polyester formation. A curing temperature of 160°C was found to be the best condition to totally avoid polymer leaching, and brought the anti-swelling efficiency (ASE) up to 64%. Decay resistance of PGS-treated wood against Trametes versicolor and Coniophora puteana was also strongly temperature and time dependent: performances fit with the EN113 standard requirements if a curing temperature of 160°C was applied.

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Protection mechanisms of DMDHEU treated wood against white and brown rot fungi

Holzforschung ◽

10.1515/hf.2009.051 ◽

2009 ◽

Vol 63 (3) ◽

Cited By ~ 30

Author(s):

Pradeep Verma ◽

Ulrich Junga ◽

Holger Militz ◽

Carsten Mai

Keyword(s):

Cell Wall ◽

Treated Wood ◽

Weight Percent Gain ◽

Brown Rot ◽

Weight Percent ◽

Decay Resistance ◽

Brown Rot Fungi ◽

Protection Mechanisms ◽

Mesh Bags ◽

Fine Wood

AbstractThe resistance of beech and pine wood blocks treated with 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU) againstTrametes versicolorandConiophora puteanaincreased with increasing weight percent gain (WPG) of DMDHEU. Full protection [mass loss (ML) below 3%] was reached at WPGs of approximately 15% (beech) and 10% (pine). Untreated and DMDHEU treated blocks were infiltrated with nutrients and thiamine prior to fungal incubation and it was observed whether the destruction or removal of nutrients and vitamins during the modification process has an influence on the ML caused by the fungi. This study revealed that no considerable differences were found. Then, the cell wall integrity was partly destroyed by milling and the decay of the fine wood powder filled into steel mesh bags was compared to that of wood mini-blocks. The purpose of this study was to examine whether the effects of surface area, cell wall bulking, and reduction in micro-void diameters play a role in decay resistance. The ML caused by the fungi, however, also decreased with increasing WPG and showed comparable patterns similar to the case of mini-blocks. ML of powder bearing the highest WPG appeared to be caused by losses in DMDHEU during fungal incubation. For brown rotted wood, the infrared absorption ratios at 1030 cm-1and 1505 cm-1revealed decreasing decay of polysaccharides with increasing WPG of treated wood.

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Evaluation of water related properties of birch wood products modified with different molecular weight phenol-formaldehyde oligomers

Holzforschung ◽

10.1515/hf-2020-0235 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Juris Grinins ◽

Vladimirs Biziks ◽

Janis Rizikovs ◽

Ilze Irbe ◽

Holger Militz

Keyword(s):

Molecular Weight ◽

Dimensional Stability ◽

Phenol Formaldehyde ◽

Treated Wood ◽

Weight Percent Gain ◽

Weight Percent ◽

Solid Wood ◽

Wood Products ◽

Birch Wood ◽

Molecular Weights

Abstract This study investigated the effect of phenol-formaldehyde (PF) resin treatment on the dimensional stability of birch solid wood and plywood. Therefore, three different low molecular weight PF resins with average molecular weights (M w ) of 292, 528, and 884 g/mol were synthesized and used for silver birch (Betula pendula) solid wood (20 × 20 × 20 mm3) and veneer (100 × 100 × 1.4 and 300 × 300 × 1.4 mm3) impregnation to produce plywood. The weight percent gain (WPG) and bulking after curing of resin treated wood specimens were determined. The leaching was performed to evaluate the PF resin fixation stability. All tested resins at all concentrations were similarly fixed in wood blocks after the leaching (1.5–2.0% WPG loss). The dimensional stability of birch wood after treatment with all tested PF resins was significantly improved. The anti-swelling efficiency (ASE) of birch wood blocks treated with PF resins after seven water soaking-drying cycles was in the range of 39–53%, 46–65% and 49–65% using 10, 15 and 20% solution concentrations, respectively. Whereas, the ASE of plywood obtained from veneers treated with 10% of PF solution was improved by 6–20%. The equilibrium moisture content (EMC) and volumetric swelling (VS) of PF treated plywood at 98% of relative humidity (RH) decreased significantly. All PF resin treated plywood surfaces were more hydrophobic compared to untreated plywood.

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An innovative method for the chemical modification of Carpinus betulus wood: a methodology and approach study

Holzforschung ◽

10.1515/hf-2018-0242 ◽

2019 ◽

Vol 73 (9) ◽

pp. 839-846

Author(s):

Ehsan Bari ◽

Ali Jamali ◽

Nouredin Nazarnezhad ◽

Darrel D. Nicholas ◽

Miha Humar ◽

...

Keyword(s):

Bending Strength ◽

Treated Wood ◽

Weight Percent Gain ◽

Weight Percent ◽

Decay Resistance ◽

Simple Method ◽

Carpinus Betulus ◽

Acetic Acid Treatment ◽

Modify Wood ◽

Impact Bending

AbstractThe objective of this research was to evaluate the influence of acetyl and methyl bonds on the physical, mechanical, photochemical and biological resistance properties of hornbeam wood.Carpinus betulus(hornbeam) wood is considered to be a less valuable species due to poor durability. In order to improve its properties, a novel and simple method was applied to modify wood samples. Hence, wood samples were modified by either acetylation or methylation at four treatment levels. Reactions between hornbeam wood and the formalin and acetic acid treatment system were successful as exemplified by increased mass [weight percent gain (WPG)], slightly better compression strength and considerably improved impact bending strength. Furthermore, the biological decay resistance of the treated wood samples increased for all of the treatments.

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Determination of decay, larvae resistance, water uptake, color, and hardness properties of wood impregnated with honeybee wax

BioResources ◽

10.15376/biores.15.4.8339-8354 ◽

2020 ◽

Vol 15 (4) ◽

pp. 8339-8354

Author(s):

Çağlar Akçay

Keyword(s):

Mass Loss ◽

Water Uptake ◽

Larval Mortality ◽

Surface Hardness ◽

Treated Wood ◽

Wood Decay ◽

Water Repellent ◽

Decay Fungi ◽

Hylotrupes Bajulus ◽

Uptake Test

The aim of the study was to determine the effect of honeybee wax impregnation on the antifungal, larvicidal, water uptake, color, and mechanical properties of wood. Wood samples (poplar, Scots pine, beech, and lime) were impregnated with melted honeybee wax under vacuum. The wax-impregnated samples were exposed to the wood-decay fungi Trametes versicolor and Neolentinus lepideus for 8 weeks. The larvicidal effect of the beeswax was tested against European old house borer (Hylotrupes bajulus L.). Water uptake, color measurements, and surface hardness were also tested. According to the obtained findings, a 34.6% mass loss was seen in the poplar control wood, and only 3.9% mass loss was found in the 100% beeswax-impregnated samples. The results showed that H. bajulus larvae could digest honeybee wax with wood when beeswax surface treatment was applied. Additionally, an average of 30% larvae mortality rate was achieved on beeswax-treated wood surfaces, compared to a 2.5% rate on the controls. However, when wood was deeply treated with beeswax, larval mortality reached 100%. In the water uptake test, beeswax-treated samples showed water repellent efficiency. The lowest water uptake (24.2%) was obtained in poplar wood treated with 100% beeswax, compared to 92.6% in the poplar control in 96 h immersion time. With the beeswax treatment, a* and b* color values increased, while the L* values decreased.

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