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Preliminary Studies on ZiBOC- A Potential Eco-friendly Wood Preservative
2005 - IRG/WP 05-30372
Over the past decade, the wood processing industry has been increasingly involved in strategies to minimize the environmental impacts of treated wood. One sign of this is the dramatic increase in the use of preservatives based on inorganic metal oxides, which fix in wood. Among such preservatives the most common is chromated-copper-arsenate. In Ascu chromium and arsenic both are carcinogenic thus in the present study a new and fixed composition of three chemicals (Copper sulphate, Zinc chloride and Sodium borate) has been used to develop an environment friendly preservative. The formulation is amorphous and water insoluble and dissolved with the help of co-solvents. Fixation study of ZiBOC in Chir and Poplar exhibited only 23.6, 13.1 and 12.1 % leachability of Copper, Zinc and Boron in Chir and 53.5, 6.5 and 5 % leachability of respective metals in Poplar. Efficient fixation of Zinc, Boron in both the species and Copper in Chir was achieved. Efficacy against Polyporous versicolar (PV) and Poria monticola (PM) a white and brown rot fungus respectively showed that 0.50% concentration of salt (3.13 kg/m3) protected Poplar completely against both the fungus as compared to control whereas PV caused 18% and PM caused 52.1% weight loss in control samples. In Chir, 0.2%(1.39 kg/m3) and 0.1% (0.68 kg/m3) concentration of salt protected blocks completely against PM and PV respectively as compared to control (54 and 11.4% weight loss caused by PM and PV). Accelerated field test after three months of installation reveals full protection of both the species against termite & fungus. Scanning electron micrograph revealed the difference of parent individual salts with the derived product. Thus, study is directed to develop synergistic biocidal compositions that combine a copper salt and inorganic biocide, removing arsenic and chromium, giving fourth generation of preservatives.
S Tripathi, J K Bagga, V K Jain

Protection of hard and softwood through Neem leaves extracts and oil - A direction towards development of eco-friendly wood preservatives
2006 - IRG/WP 06-30394
Conventional wood preservatives like CCA and CCB are facing lot of criticism all over the world. It is essential to address the problem in view of environment protection. Eco-friendly wood preservatives may be considered as one option. The present study is an expolartion of neem leaves and seed oil against wood decaying fungi and termites. Azadirachta indica A. Juss, commonly known as neem is one of the most widely recognized and extensively studied plant specie of Indian sub-continent. Every part of the tree has been thoroughly evaluated for its marked activity against insects, microbes, pests etc. and has gain world-wide recognition as potential therapeutic agent. Neem is considered to be a store-house of various biologically active compounds such as azadirachtin, salanin, nimbin, quercetin etc. all of them are reported to possesses marked antifeedant, anti-microbial and anti-bacterial activity. The activity of alcoholic extract against wood decaying fungi i.e. Postia placenta and Trametes versicolor in hardwood i.e. Populus deltoides and softwood i.e. Pinus roxburghii at different concentrations revealed 4 to 7 fold protection of wood over to control. 80-82% protection was observed in samples of hard and softwood treated with leaves extracts when subjected against wood destroying termite i.e. Microcerotermes bessoni in laboratory. Neem oil at various concentrations protected hard and softwood efficiently against fungi i.e. upto 4 to7 fold over to control. Hard and softwood samples treatred with neem oil exhibited only 9-10% of weight loss by termites in laboratory whereas 95% damage was recorded in control samples. Present study shows that further work on neem oil and leaves extracts is required to develop potential eco-friendly wood preservative.
S Dhyani, S Tripathi

Reduction of Environmental Toxicity Through Eco-friendly Wood Biopreservative
2007 - IRG/WP 07-50243
Many chemicals are used today to enhance the durability of wood and wood-derived products that are very important in our life. Such chemicals are copper, chromium, arsenate, zinc, etc. Though these preservatives are useful to protect wood from biodeterioration, but environmental toxicity is also related with them. The present study is to investigate the fungitoxic activities of Dalbergia sissoo leaves instead of chemicals. Acetone with five different concentrations was used as solvent to isolate the leaf extract of Dalbergia sissoo. The extractives were then used to see the inhibition activity over the soil fungi and other microbes. Experiment has showed that 3.0% concentration of acetone as solvent with leaf extract showed best result in inhibiting the attack of soil fungi and bacteria. For treating with aforesaid concentration of acetone, wood sample showed lowest loss of weight (22%). From this investigation, it can be assumed that biological preservative is a tool of protecting wood and thus environmental toxicity and biodiversity can be maintained.
A Humayan Kabir, M Firoz Alam

Efficacy of Neem (Azadirachta indica) Leaves Against Wood Decay Fungi
2008 - IRG/WP 08-30450
Many plant-derived substances have fungitoxic, pecticidal and insecticidal ability. Neem leaves are very popular in this respect since the ancient time. The present study is to investigate the fungitoxic activities of neem leaves extractives against wood decay fungi. Three different solvents, i.e. acetone, methyl alcohol, ethyl alcohol, were used to isolate the extract of neem leaves. The extractives were then used to see the inhibition acitivity over the test fungi in laboratory and natural condition. Both results proved that 3% concentration of acetone extract is best for inhibiting the growth of test fungus. Acetone and methanolic extract was also effective against that decay fungus. From this investigation, it is established that neem extract is potential source of biological preservative of wood and it can be used in any wood related commercial purposes.
A Humayan Kabir, M A Rahman, M Firoz Alam

Eco-Friendly Composites from Bagasse and Soy-based Resin
2009 - IRG/WP 09-40462
In this study, bagasse and soy-based resin were used for producing composite materials. The objective of this study was evaluation of some physical and mechanical properties of boards made of various ratios (100:0, 60:40, 40:60 and 0:100) of bagasse to wood fiber mixtures (wt: wt) with addition of Soy/PF resin at three levels (4, 8 and 10%) and 1.5% wax. All properties were tested according to ASTM D-1037 and all data were analyzed statistically. The results showed that by increasing bagasse fibers all properties of boards were deteriorated but by addition of 10% soy/PF resin all of them were improved significantly. Boards made of 40:60 ratio of bagasse to wood fiber mixtures and 10% Soy/PF resin content have acceptable bending strength and those are made of 100% bagasse and 10% Soy/PF resin content meet the requirements set for internal bond strength of the ANSI 208.2-1994 for interior uses.
G Rassam, B Jamnani

Towards designing eco-friendly buildings with in-built termite protection
2010 - IRG/WP 10-50273
The increase in greenhouse gases, leading to global warming, is considered by a consistent scientific worldview not due to natural variation, but due to the growing concentration of carbon dioxide (CO2), methane (CH4) and other atmospheric pollutants. Global emissions of carbon dioxide from fossil fuel combustion and cement production rose from 22.6 billion tons in 1990 to an estimated 31.2 billion tons in 2007 – a staggering 37 percent increase. This is 85 million tons of carbon dioxide spilled into the atmosphere each day – or 13 kg on average per person. The realisation that saving the global climate and protecting ecosystems, now and in future, in a warming world, affects everyone. So, how are the IRG members and IRG as an institution, which include the building, chemical, academic, and pest control industries dealing with the challenge of global warming in sustaining their businesses? Can we advise these industries to make choices to minimise the impact of global warming and minimise their carbon footprints? Can IRG convey to the world at large the profound long-term consequences of the ‘experiment’ we are now conducting with Earth’s atmosphere, with emphasis on a sustainable wood protection industries. Furthermore, on the biological level, we have scant data on the effects of climate change to the distribution, ecology, biology and control of wood-destroying insects and wood-decay bacteria and fungi. Preliminary field tests were carried out against Coptotermes species at Caloundra in Queensland (Qld) and Nhulunbuy in Northern Territory (NT). The test samples were exposed to active above ground mound colonies of Coptotermes lacteus in Caloundra and Coptotermes acinaciformis in Nhulunbuy and there was no visible evidence of feeding or tunnelling into the Hemcrete® samples. In this paper, with global warming in mind, we offer suggestions to the timber, building, chemical, and pest control industries to consider the advent and utilisation of bio-composite, carbon negative products, such as, Hemcrete®. We consider this product meets the challenge of an eco-friendly building product that is termite resistant.
J R J French, B M Ahmed Shiday, B Maggiolo, D Maggiolo

Fire performance of the wood treated with retardant
2012 - IRG/WP 12-40591
To prepare the eco-friendly fire retardant wood, Japanese red pine (Pinus Densiflora), hemlock (Tsuga Heterophylla), and radiate pine (Pinus Radiata) were treated with inorganic chemicals, such as sodium silicate, ammonium phosphate, and ammonium boric acid. Different combination and concentration of those chemicals were injected by pressure treatment methods. The electron-beam treatment was used to increase the chemical penetration into the wood. The fire performance of the fire retardant was investigated. The penetration of chemicals into the wood was enhanced after irradiation of 200 kGy of electron beam. Ignition time of the treated wood was the most effectively retarded by sodium silicate, ammonium phosphate, and ammonium boric acid. The most effective chemical combination was found at 50% sodium silicate and 3% ammonium boric acid; which showed 3-grade flammability defined in the KS F ISO 5660-1 standards.
Jong In Kim, Mi-ran kang, Sang bum Park, Dong won Son

Bio-based thermoset resins for bonding and eco-friendly preservation in the wood industry
2013 - IRG/WP 13-40650
Yellow dextrins and tannins were used in wood adhesives formulation to substitute resins based on formaldehyde. Several formulations were carried out in alkaline aqueous media by varying the weight fraction of two compounds from 10% to 30%. The cross-linking was performed using epichlorohydrin as a reticulant agent. Rheological behaviours and initial adhesion of three liquid formulations, before reticulation, were carried out by probe tack test and Rheology to validate its process ability. The cross-linking of epichlorohydrin with yellow dextrins and tannins was highlighted in this study. The cross-linking was analyzed by Fourier transformed infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and by biodegradation of reticulated resins. Mechanical properties of resins were analyzed by shear strength test on plywood. Depending on formulations, results confirmed the high potential of yellow dextrins and tannins reticulated by epichlorhydrin, to glue wood. Moreover, the biodegradation tests of cross-linked samples showed that the network constituted by dextrins and tannins are resistant to fungal attack.
C Motillon, A Allal, A Visse, F Charrier, B Charrier, A Baldé

Efficacy of Erythropleum suaveolens (potrodom) and Distemonanthus benthamianus (bonsamdua) water extractives on the durability of five Ghanaian less used timber species of varying perviousness and retentiveness
2017 - IRG/WP 17-30705
Conventional wood preservatives are not only toxic to target bio-deterioration organisms but also to humans, other organisms and the environment. In an effort to find preservatives that are less toxic or non-toxic to man, other organisms and the environment, efficacy of branch bark and heartwood water extracts (0.65 g/ml) of Erythropleum suaveolens (potrodom) and Distemonanthus benthamianus (bonsamdua) were tested on five less used species (LUS) namely, Sterculia oblonga (ohaa), Antiaris toxicaria (kyenkyen), Canarium bediwonua), Celtis zenkeri (esa-kokoo) and Cola gigantea (watapuo) of varying perviousness and retentiveness from varying contents of hydrophobic and water-repellent extractives and/or extraneous substances in wood and/or vessels. Bonsandua extracts were more resistant to leaching, but potrodom extractives improved the durability of Canarium schweinfurthii more than bonsamdua extractives. Potrodom bark extracts could be readily employed to preserve non-recalcitrant low durability timber species such as C. schweinfurthii, and possibly recalcitrant low durability ones such as S. oblonga after some form of pre-treatment and/or under pressure conditions. Improved durability of immersed and brushed LUS was ranked as follows: C. gigantea > C. zenkeri > S. oblonga > A. toxicaria > C. schweinfurthii proving that the natural durability of timber is somewhat dependent on their level of recalcitrance from intrinsic hydrophobic and/or water-repellent extractives and/or extraneous substances. Though extracts showed reduced efficacy with time, the use of potrodom extractives for the preservation (control of pests) of non-recalcitrant low durability wood is promising.
A Asamoah, K Frimpong-Mensah, C Antwi-Boasiako

Aiming for eco-friendly log production and wooden construction!
2021 - IRG/WP 21-50365
In order to reduce greenhouse gas (GHG) emissions to zero by 2050 in the fields of forest and forest products, it is necessary to promote appropriate management and renewal of planted forests, and development of wooden building materials and the wooden construction of mid-to-high-rise buildings with lower GHG emissions. Unless we also try to reduce the environmental loads other than GHG for such development, we cannot simply replace it with other materials and construction methods. Therefore, we assessed GHG emissions up to the production of domestic logs which are the raw materials for all wood-based materials. The environmental loads of an office building made of the fireproof glulam impregnated with fire-retardant and an apartment using gypsum board-covered CLT were also assessed with those of steel-framed and reinforced concrete buildings. As a result, in log production, it is necessary to reforest after clear-cutting, and in order to give mid-to-high-rise wooden buildings the fire resistance required in Japan, gypsum board should not be used or alternatives with low environmental impact should be used.
N Hattori

Eco-tax - A new threat for wood preservation? The Belgian experience
1993 - IRG/WP 93-50001-32
At the end of January 1993, a bill was put for Belgian Parliament related to the introduction called "Eco-taxes" on a series of products, such as packaging for drinks (especially on PVC-bottles), non-returnable articles (shavers, small cameras), batteries, pesticides for non-agricultural use and paper.
G Van Steertegem, F De Jaeger

Silafluofen, a new insecticide against wood-boring insects and termites
1991 - IRG/WP 3666
Hoe 084498 (proposed common name: Silafluofen) is a new insecticidal compound from Hoechst Aktiengeesellschaft and has been extensively tested to determine its potential use as an insecticide against wood-boring insects and soil termites. Various tests in official institutes indicate a good activity against several wood-boring insects and soil termites. The active ingredient is resistant to weathering (leaching and evaporation) of treated wood. Hoe 084498 is suitable in solvent-borne and water-borne formulations and compatible with fungicides such as triazoles and quaternary ammonium compounds. The physical and chemical properties, such as odour, vapour pressure, solubility and pH-independency, are favourable. An extensive toxicological and eco-toxicological file has been composed in accordance with OECD and EPA guidelines.
G Rustenburg, C J Klaver

Combustion properties of Alder wood treated with some new environment friendly natural extractives. Part 1. Effect of Natural Tannins on the Combustion Properties
2002 - IRG/WP 02-40234
Powders of the brutia pine bark, sumach leaves, acorn, gall-nut and boric acid and borax which are known as potential environment friendly wood preservatives were impregnated according to ASTM D 1413-88 in order to determine their combustion properties. A commercial treatment compound, Tanalith-CBC, was also used for comparison. The results indicated that the natural extractives did not have any effect on combustion properties of alder wood and showed the same fire properties with control sample. However, when wood samples were treated with first natural extractives then boron compounds solution sequentially, the combustion properties were reduced.
Ü C Yildiz, A Temiz, E D Gezer, S Yildiz

The Development of a novel method to preserve reeds using an environmentally friendly timber preservative and a unique engineering design.
2006 - IRG/WP 06-40335
Reeds are used in the construction of bush lodges in Northern Kwa- Zulu Natal, South Africa. Fungal, insect and ultra-violet damage to these reeds is posing a severe problem. Within a space of two years, the reeds are attacked and have to be subsequently replaced; a time consuming and costly exercise. A novel method has been used to successfully preserve these reeds with an environmentally friendly preservative containing disodium octaborate tetrahydrate in a water-based polymer system. The polymer allows for uninhibited diffusion of boron into the reeds, whilst the polymer cures to form a continuous protective film. By making use of two strategically drilled holes, which are 2 mm in diameter, the preservative is introduced into the reed shafts and nodes. The boron successfully diffuses into the walls of the reeds and is prevented from leaching out of the reeds. The water-based polymer provides sufficient protection against excessive ultra-violet damage. The test site, which is situated in the Hluhluwe Game Reserve in Northern Kwa-Zulu Natal – South Africa, has been monitored for nearly two years and there are no sign of insect or fungal damage to the reeds. Over the two-year period, the reeds were periodically inspected for deterioration in colour and deterioration in structural integrity.
K Govender, K G Moodley

Furfurylated wood - An alternative to Preservative-treated wood
2006 - IRG/WP 06-40349
Chemically modified wood is currently being marketed as a non-toxic alternative to traditional preservative treated wood (wood impregnated with biocides). Over the last decade the authors have developed modernised processes for wood modified by furfurylation. These new systems do not add metals or halogens to the product, which is important for an environmentally acceptable product. This presentation deals with the environmental aspects and durability of furfurylated wood. Results from several decay tests; emission analysis studies and eco-toxicity tests are presented. . The results show that furfurylated wood is highly decay resistant. There was no significant eco-toxicity of water leached from furfurylated wood and burning furfurylated wood does not release any more volatile organic compounds or poly-aromatic hydrocarbons than normal levels for wood combustion. Durability enhancement by furfurylating wood has not proven to be harmful to the environment. Test results have shown it to have performance similar to traditionally preserved wood. Furfurylated wood has some improved mechanical and physical properties such as increased modulus of elasticity (MOE) and increased anti shrink efficiency (ASE).
S Lande, M H Schneider, M Westin, J Phillips

Antifungal Activities of Three Supercritical Fluid Extracted Cedar Oils
2009 - IRG/WP 09-30501
The antifungal activities of three supercritical CO2 (SCC) extracted cedar oils, Port-Orford-cedar (POC) (Chamaecyparis lawsoniana), Alaska yellow cedar (AYC) (Chamaecyparis nootkatensis), and Eastern red cedar (ERC) (Juniperus virginiana L), were evaluated against two common wood decay fungi, brown-rot fungi (Gloeophyllum trabeum) and white-rot fungi (Trametes versicolor). The statistical analysis showed that SCC extracted cedar oils had higher antifungal activities othan hexane Soxhlet extracted cedar oils against both white-rot fungi and brown-rot fungi. In vitro studies showed that AYC oils showed the strongest antifungal activity among the three cedar wood oils, followed by POC oil and ERC oil.
Tianchuan Du, T F Shupe, Chung Y Hse

Performance classification of wood in construction – drafting a user friendly European standard
2014 - IRG/WP 14-20545
The performance classification for wood products in construction is an extremely important topic in Europe and beyond – warranty providers and end users demand service life and performance information in the face of competition with other materials. The European project PerformWOOD has formalised and drawn together the on-going research to focus on generation of a material resistance factor for performance classification and alongside WG28 is developing the first moisture dynamic test protocols in the Technical Committee’s history, again based on research work being drawn together. In this paper some of the early concepts around a future user friendly standard to enable wood and enhanced durability wood to be specified by construction professionals on the basis of performance are considered. A draft standard (EN460) for consideration of performance classification of wood in construction is underway and relies on concepts that are being road-tested with industry, construction professionals, researchers and the general public.
E Suttie, C Brischke, L Meyer, J Van Acker, M Kutnik, E Heisel, F Englund, J Jermer, S Thelandersson, M Polášek, D Lorenzo

Short-term protection of palm wood against moulds and decay fungi by environment-friendly organic acids
2015 - IRG/WP 15-10843
Felled palm trunks are susceptible to fungi as long as their moisture content is above fibre saturation. During this period, it has to be protected against moulds and decay fungi. The study tested environmental-friendly organic acids for their protecting efficiency. Small samples of Date palm (Phoenix dactylifera) and Oil palm (Elaeis guineensis) wood were treated with weak organic acids and subsequently infected by moulds and wood-decay fungi. Short dipping of the samples in solutions of 5% acetic acid and propionic acid, respectively, protected all samples for two months from colonization by Aspergillus niger, Penicillium sp., Cladosporium sp., and by a natural infection. Boric acid (4%) used in practice for protection was ineffective. Decay tests with the white-rot fungus Pleurotus ostreatus, the brown-rot species Coniophora puteana and the soft-rot fungus Chaetomium globosum showed that both acids prevented most samples from fungal colonization and reduced decay considerably during two months.
M Bahmani, O Schmidt

Bio-friendly preservative systems for enhanced wood durability - the first periodic report on DURAWOOD
2015 - IRG/WP 15-30677
The objective of the paper is the DURAWOOD scientific project carried out within Polish-Norwegian Research Programme, which lasts from September 2013 till August 2016. The aim of the project concentrates on the developing of a new, eco-friendly and biocide-free wood protective systems as an alternative to traditional, commonly used preservatives or coatings, containing biocides. Several wood preservatives containing traditional biocides are no longer desired on the market, due to the stricter toxicological requirements and an increasing ecological awareness of consumers. Therefore, formulating new wood protective systems, based on natural compounds, harmless to humans and the environment, is of the principle interest. On the other hand, it will also facilitate a longer period of carbon capture in wood, which will limit the greenhouse effect. Life cycle assessment (LCA), which is planned to perform for the selected model formulations, is a good example for an attempt to explain the interest. Besides, the implementation of novel solutions in wood protection will make it possible to use low quality wood material to manufacture high quality products (e.g. siding or cladding materials). In this manner such eco-friendly wood protection will be also a key factor reinforcing climate protection. The aim of this paper is to present some selected results gained so far. The model wood protecting systems were based on natural (alkaloids, propolis, plant oils) and synthetic (organosilicones, imidazoles) components as well as on neutral inorganic chemical - potassium carbonate. They were used individually or as a formulation for wood treatment. Wood samples made of Scots pine were treated by soaking or vacuum method and were subjected to mycological and fire tests. The so far results show that aminosilanes and mixtures thereof with natural oils are potential wood preservatives against microfungi and wood destroying fungi. Formulations containing aminosilanes, natural oils and potassium carbonate are potential wood fire retardants. It was also found that the most effective alkaloids were cytisine derivatives and caffeine. The highest antifungal activity among tested imidazoles was achieved by AK17 (1,10-di(3-hydroxymethylpyridinium)decanedibromide). The results of chemical analysis present evidence of interactions between compounds of the model formulations and wood chemical components.
B Mazela, M Broda, W Perdoch, L Ross Gobakken, I Ratajczak, G Cofta, W Grześkowiak, A Komasa, A Przybył

Decay resistance of wood treated with bio-friendly preservative systems
2016 - IRG/WP 16-30698
Due to more restrictive toxicological requirements and increased ecological awareness of consumers, wood preservatives containing biocides are no longer desired on the market. Therefore, research on new environmentally friendly formulations is of great importance. One of the possible solutions is to develop new preservatives based on natural substances, which are harmless to humans, animals and the environment, while biologically active. The aim of the study was to develop new biocide-free preservative systems which increase wood resistance to wood-decaying fungi. The following silanes: [3-(2-Aminoethylamino)propyl]trimethoxysilane (AATMOS), (Aminopropyl)triethoxysilane (APTEOS), and (Aminopropyl)trimethoxysilane (APTMOS); caffeine, natural oils and potassium carbonate were chosen as components of new protective formulations, which were planned to be an alternative for traditionally used biocides. Samples of three different wood species (pine, spruce, and poplar) were treated with the new preservative systems and exposed to brown-rot fungus Coniophora puteana and white-rot fungus Coriolus versicolor according to EN113 or EN839 standard. The obtained results show that wood treated with the water-based formulation consisting of silanes and caffeine (2% caffeine + 5% AATMOS, 2% caffeine + 5% APTEOS) demonstrated the highest resistance to the test fungi. Wood mass loss after exposure to fungi was 1%. All wood species treated with this formulation achieved index 1 (“very resistant”) within durability class acc. to EN-350 standard.
B Mazela, G Cofta, W Perdoch, L Ross Gobakken, P Kwaśniewska-Sip

Copolymers of tannin extracts as wood protection agents
2017 - IRG/WP 17-30709
Wouldn´t be a dream to preserve wood with the substances which the nature already synthesizes for protecting itself? The idea we would like to pursue is simple: Increase the concentration of these substances, the tannins, trying to fix them properly in wood. It appears easy but it is not. Sensibility against leaching, fungal decay and weathering were observed. In this paper new flavonoid co-polymers were studied for their leaching resistance and their biocidal activity once fixed in wood. These formulations added of low amount of biocides have demonstrated to be: i) hardening- (time & temperature) dependent in terms of water resistance and ii) requiring small amount of biocide (Boron and/or copper) for resisting the attack of white-rot Coriolus versicolor fungi. Interesting perspectives for natural preservatives are opened again.
G Tondi, L Sommerauer, A Oberle, A Petutschnigg, M-F Thevenon

Bio-friendly wood protection systems - resistance to mould and blue-stain fungi
2017 - IRG/WP 17-30713
With stricter restrictions on the use of biocides and increasing environmental awareness there is a pronounced need for effective bio-friendly protection systems in the wood preservative and wood coating industry. One of the possible pathways is to exploit and utilize natural substances with active biological effects. Silanes, caffeine, natural oils and potassium carbonate were chosen as compounds in 16 different formulations intended as wood protection systems. The aim of this study was to test the resistance of the selected protection systems against mould growth and growth of blue-stain fungi. Combination of caffeine and amino functional silanes showed good resistance towards blue-stain fungi when applied to pine and the same was found for the combination of linseed oil and amino functional silanes. Some indications of resistance towards mould fungi were also detected for the same chemical combinations.
L Ross Gobakken, W Perdoch, B Mazela, P Kwaśniewska-Sip, G Cofta

Green approach in wood mineralization for improvement of fire properties
2022 - IRG/WP 22-30769
Various treatments have been developed in order to improve fire properties of wood. Because the use of some flame retardants can release toxic compounds in the event of a fire, leading to poisoning or even death of people from smoke inhalation, the use of no-toxic and more ecologically acceptable flame retardants is preferable. Mineralization of wood with the incorporation of carbonates has proven to be a promising method for improving fire properties. The paper presents fire properties of two wood species (spruce and beech) modified using recently proposed eco-friendly mineralization process. Method is based on vacuum pressure impregnation using water solution of calcium acetoacetate which transforms to CaCO3 deep inside the wood structure. The parameters for determining the classification of reaction to fire were investigated. The increase in time ignition, decrease in the total heat release and the fire growth rate index were observed for mineralized wood. Moreover, reduced weight loss in different pyrolysis process of mineralized wood determined by thermogravimetric analysis indicates improved fire performance of such material.
A Pondelak, R Repič, L Škrlep, N Knez, F Knez, A S Škapin

Environmentally Friendly Wood Modification based on Tannin-Furfuryl alcohol - Effect on stabilisation, mechanical properties and decay durability
2022 - IRG/WP 22-40929
Furfurylation is a well-known wood modification technology. This paper studied the effect of tannin addition on the wood furfurylation. Three kinds of dicarboxylic acids, adipic acid, succinic acid, and tartaric acid, as well as glyoxal as a comparing agent, were used to catalyse the polymerisation of furanic or tannin-furanic solutions during wood modification. Impregnation of furanic or tannin-furanic solution at a certain concentration into the wood followed with curing at 103°C for a specific duration was performed for the wood modification. Different properties of the modified woods like dimensional stability, resistance of treatment to leaching, mechanical properties, decay durability against white-rot (Coriolus versicolor, Pycnoporus sanguineus) and brown-rot (Coniophora puteana) as well as their chemical and anatomical characteristics were evaluated. Results revealed that the partial substitution of FA by the tannins improved the fixation of the chemicals impregnated in wood. Further, dimensional stability, leaching resistance, Brinell hardness, modulus of elasticity/modulus of rupture, and decay durability properties of the furfurylated wood were also improved in the presence of tannins. Scanning electron microscopy revealed the polymerisation of the polymer in the wood lumen cells and in the wood cell walls.
M Mubarok, E Azadeh, F O Akong, S Dumarçay, A Pizzi, C Charbonnier-Gérardin, P Gérardin

Improving wood durability by mineralisation and thermal modification
2022 - IRG/WP 22-40948
A significant increase in the fungal durability of wood was achieved by using a modification procedure combining two environmentally friendly methods: thermal modification and mineralisation. It offers an ecological alternative to other biocidal treatments. European beech (Fagus sylvatica) and Norway spruce (Picea abies) were selected as model wood species and exposed to four different fungi: Gloeophyllum trabeum, Rhodonia placenta, Trametes versicolor and Pleurotus ostreatus. The highest durability against Rhodonia placenta, Trametes versicolor and Pleurotus ostreatus was achieved through thermal modification in both wood species. The newly proposed mineralisation and thermal modification combination was the most effective against Gloeophyllum trabeum. At the exposed samples, we found that modified wood is less vulnerable to fungal decay than the reference wood. The slightly alkaline environment of both mineralised wood species is one of the parameters likely to slow down fungal activity compared to the more acidic environment of the reference and thermally modified wood.
R Repič, A Pondelak, D Kržišnik, M Humar, A S Škapin