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Monitoring uptake and penetration of pesticides during impregnation of pine (Pinus sylvestris) and spruce (Picea abies) wood with bio-based microemulsion gel formulations
2020 - IRG/WP 20-30756
Even in dry state wood is susceptible to biological degradation. Preservation against biological decay in exposed conditions is conventionally achieved by impregnating the wood with pesticides applied at professional and industrial levels. Impregnation of wood with preservatives is a complex process that involves wood macro- and microstructure, and the physical characteristics of woods. Here we focused on pine (Pinus sylvestris), an easily impregnable species, as opposed to spruce (Picea abies), a refractory species. In this work, the two species were impregnated with commercial bio-based emulsion formulations containing insecticide and fungicide agents. Penetration and uptake of the active agents were evaluated on laboratory specimens. The impact of different modes of application, dipping, surface spraying, and vacuum-impregnation, on the retention and distance of penetration of the active agents, cypermethrin, permethrin and propiconazole was assessed by gas liquid chromatography coupled to mass spectroscopy. Due to the suitable combinations of solvents and surfactants of our bio-based emulsions of low-toxicity and minimal environmental impact, rapid wood penetration enabled high retention yields. The difference of penetrability of pine versus spruce is discussed in relation to their anatomical characteristics, and their conducting cells network. The present data demonstrate the penetration and retention performances of these bio-based formulations.
D Messaoudi, K Ruel, J-P Joseleau


Copper based water-borne preservatives: The biological performance of wood treated with various formulations
1987 - IRG/WP 3451
Wood samples treated with the various components of CCA preservative singly and in combination were tested against a soft rot organism, a copper tolerant brown rot organism and in soil burial both unleached and after leaching. The results suggest that, of the elements tested, fixed copper is essential for preventing soft rot attack and fixed arsenic is essential for preventing attack by a copper tolerant brown rot organism in leaching environments.
S M Gray, D J Dickinson


Fungicidal activity of some new water borne copper octanoate based formulations
1999 - IRG/WP 99-30198
Four new water borne formulations for preservation of wood were prepared: the composition of Cu(II) octanoate, 2-aminoethanol (ethanolamine) and water; the composition of complex of Cu(II) octanoate with nicotinamide, 2-aminoethanol and water; the one of Cu(II) octanoate, organic boron complex, 2-aminoethanol, dimethyl sulfoxide and water and finally, the mixture of Cu(II) octanoate, diazene, 2-aminoethanol and water. Fungicidal activity of these new formulations against Trametes versicolor, Antrodia vaillantii and Coniophora puteana was determined by filter paper and mini-block test methods. Compared to the commercially used wood preservative containing Cu(II) naphthenate / Cu(II) 2-ethylhexanoate, the new compositions have stronger fungicidal activity. The strongest biocidal activity was exhibited by the formulation with a Cu(II) octanoate/nicotinamide complex.
M Petric, M Pavlic, F Pohleven, P Segedin, B Kozlevcar, S Polanc, B Stefane, R Lenarsic


Penetration of surface applied deltamethrin micro-emulsion formulations in four European timber species
1994 - IRG/WP 94-20030
The Netherland's Government, in line with many other European Governments initiated a programme (KWS2000) aimed at significantly reducing the emission of volatile organic compounds by the year 2000. As part of this programme a research project is currently underway to evaluate the potential for replacing organic solvent based remedial treatments with micro-emulsion formulations of the same or enhanced insecticidal activity. To date the project has evaluated the penetration of a deltamethrin micro-emulsion formulation in four species, notably, Scots pine (Pinus sylvestris) sapwood and heartwood, Norway spruce (Picea abies) heartwood, Douglas fir (Pseudotsuga menziesii) heartwood and European oak (Quercus petraea) heartwood. The test method used, an adapted version of the German standard DIN 52 162, subsequent a.i. distribution analyses and results are discussed.
P Esser, W L D Suitela, A J Pendlebury


Analysis of water repellents in wood treated with water borne formulations using FTIR
2000 - IRG/WP 00-40176
The use of aqueous water repellent emulsion formulations has increased significantly in the wood treatment industry. These products are primarily used to enhance the weathering characteristics of wood products treated with water borne preservatives systems used in exterior above ground applications. They are also used in pole treatments to improve climbing characteristics and in low VOC millwork treatments. With the increasing usage of such products. there has been a need to develop analytical methods for the determination of the water repellent in treated wood products to ensure product quality and to aid in the development of enhanced water repellent formulations. A method for the determination of the water repellent concentration in wood was developed using Fourier transform infrared spectroscopy (FTIR). The wood samples were extracted and prepared for the FTIR scans using a liquid cell. The water repellent concentration was determined by using the intensity of the hydrocarbon C-H stretch adsorption. Methods for correcting or eliminating the interference from non-water repellent components in the wood extracts were developed.
P J Walcheski, L Jin


An evaluation of the synthetic pyrethroid cypermethrin in organic solvent and emulsion formulations
1984 - IRG/WP 3290
The studies reported indicate that cypermethrin (NRDC 149) has considerable potential as an insecticide for wood preservatives. Cypermethrin appears to be about twice as effective as permethrin. The effectiveness of cypermethrin compared with g-HCH varies depending on the insect species, the phase of the life cycle and size of larva: for example, against mature Anobium larvae cypermethrin is approximately equal to g-HCH in effectiveness, but against egg larvae it is four times more effective. Against emergence of Anobium adults an organic solvent formulation containing 0.1% cypermethrin was more effective at 16 months than the g-HCH solution which was ten times stronger. Against mature Hylotrupes larvae it is approximately four times more active than g-HCH but as a surface spray against Lyctus a concentration of cypermethrin fifty times less than that used commercially for g-HCH spray treatments prevented infestation. Bioassay tests with a range of wood-boring insects reveal broad spectrum activity and considerable resistance to standardised accelerated evaporative ageing. In emulsion formulation cypermethrin at 0.1% prevented emergence of Anobium adults for 5 years, and was effective against attack by termites. A 0.01% emulsion formulation prevented infestation by Lyctus. In organic solvent formulation 0.1% cypermethrin gave an acceptable level of mortality against both Anobium and Hylotrupes larvae and prevented emergence of Anobium adults at 26 months.
S J Read, R W Berry


Accelerated termicidal performance data for new water-based copper linoleate formulations
1996 - IRG/WP 96-30104
An organic solvent based copper linoleate (Culin) has proved itself as an effective wood preservative in long term field trials in South Africa over a period of 30 years. Whilst the organic solvent based product offers good wood preservative performance, primary industrial interest has been in an emulsified version of the product. The objective of this study was to evaluate the influence of two different emulsifiers on the performance of emulsified versions of Culin against subterranean termites under accelerated field test conditions. The results indicated that the emulsions offered levels of protection that did not differ significantly from that of the original Culin formulation and CCA at equivalent copper retentions. However, variations in the performance of the products in the test indicated that the choice of emulsifier could influence the predictability of the products in the field.
D Conradie, P Turner


Microemulsion formulations for wood protection chemicals
1993 - IRG/WP 93-30030
A microemulsion is a thermodynamically stable oil-water dispersion system. As a formulation it provides many unique features such as water compatibility for water-insoluble chemicals, formulation stability, good bioavailability and environmental acceptance. This paper discusses the major criteria for the formulations of water-insoluble wood biocides and the comparison in properties between conventional emulsions and microemulsions. Water-dilutable microemulsion technology has been developed at Rohm and Haas Company. Several such microemulsions for a broad spectrum wood biocide, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, have been evaluated regarding wood penetration and leachability. The results indicated that the active ingredient has a deeper penetration in the wood treated by microemulsions than by emulsion and solvent formulations. The leachability of the active ingredient in this study depends upon the formulation components and will be further investigated.
Bing Yu, L E Leightley


The development of a new boron-based wood preservative
1995 - IRG/WP 95-30085
The paper describes a new boron based wood preservative for the treatment of green timber. The product offers many benefits over conventional boron diffusion treatment including: 1. high viscosity, high concentration formulation; 2. permits dip treatment of a wide range of sawn board and pole sizes at ambient temperatures; 3. permits full cross section diffusion of borates without block stacking and wrapping of treated material; 4. treated material is ready for use within a few hours after dipping, this eliminates long storage periods; 5. a water-repellent coating which acts both as a leach retardant and protects the timber against weathering; 6. the new product permits the use of borates in H3 class situations. Evaluation of diffusion trials and simulated rain test data on treated material is discussed.
P Turner, D Conradie


Investigation of new wood preservation formulations based on synergies between antioxidant, 2-HPNO and Propiconazole
2006 - IRG/WP 06-30401
Wood degradation by fungi is a complex phenomenon taking place in part through oxidative reactions involving many oxidizing agents like free radicals and hydroperoxide. In order to develop novel and more environmentally benign preservative systems, mixtures of Propiconazole and antioxidants with different stabilization mechanisms were investigated to detect possible synergies allowing to reduce the quantity of biocide to prevent wood biodegradation. Results obtained showed that the nature of the antioxidant had an important effect on the potential synergies. The most interesting results were obtained with 2-HPNO and hindered amine and to a weaker extend with H-donors like hindered phenol.
B Bakhsous, S Dumarçay, E Gelhaye, P Gérardin


Methods for Studying Penetration Depth of Wood Protection Products
2010 - IRG/WP 10-20432
EN 152 is an accepted standard in Europe for measuring how deep a wood protection product penetrates into the surface of treated pine wood. The method has provided consumers with a wide assortment of products that meet the specifications outlined in the standard. Because the test takes 8 or more months to carry out, artificial ageing procedures have evolved in order to standardize and speed up the procedure. Small changes in a formulation will often change a products physical parameters and especially its ability to penetrate into wood. It is therefore desirable to develop a method that can measure changes in a product’s penetrability quickly and accurately. A method is described where wood cores are drilled from treated wood, then sliced in 100 µm thick discs. Discs are then placed on nutrient agar plates seeded with conidia from Aspergillus niger. Plates are incubated for 24 hours and zones of inhibition are measured. It is believed that if a fungus is growing on the disc the biocide level will not exceed that of the fungus minimum inhibition concentration (MIC). In water based acrylic systems penetration depths are often less than one mm and it can impact the performance of a product if that changes. The procedure described in this study can show if penetration of a preservative product has been increased or reduced in as little as 24 hours.
K Hansen, L Sites, D D Nicholas


Evaluation of formulation type on the efficacy of bifenthrin as a glueline termiticide for veneer based wood products
2010 - IRG/WP 10-40486
Field trials were carried out in Australia on Coptotermes acinaciformis to evaluate the efficacy of various bifenthrin formulations. One trial tested plywood made by Zelam at their research facility in New Zealand and compared three emulsifiable concentrate formulations (EC), a suspension concentrate (SC) and an encapsulated formulation (CS). A second trial compared laminated veneer lumber (LVL) made at a commercial mill in New Zealand and compared EC and CS formulations. A third trial used LVL made at commercial mills in New Zealand and Australia and compared CS and SC formulations respectively. Trial results show zero attack on the engineered wood samples when glueline and surface applications were used. Glueline only treatments resulted in some surface grazing but no penetration into centre veneers. In all trials there was no significant differences in efficacy between the formulation types.
P Lobb, A Siraa


Effects of intumescent formulation of vinyl acetate-based coating on flame-retardancy of thin painted red lauan (Parashorea spp.) plywood
2011 - IRG/WP 10-40537
Using intumescent coatings on wood-based materials is an effective method for fire safety. The intumescent coatings consist of four major components: (1) binder resin (BR), (2) carbonizing substance (CS), (3) foam producing substance (FPS) and (4) dehydrating agent (DA). Previous studies have demonstrated that the formulation of the four components strongly influences the performance of coatings. This study investigated the effect of intumescent formulation of vinyl acetate-based coating on flame-retardancy of plywood. Two sorts of widely used binder resin (BR) for vinyl acetate-based coating, ethylene vinyl acetate copolymer (EVAc) and vinyl acetate acrylic copolymer (VAC), were used. The fire retardancy of coatings on plywood was assessed by a cone calorimeter. Total heat release and time to peak heat release rate are the two primary parameters. The data showed that lower BR and FPS content decreased total heat release and lengthen time to peak heat release rate. This mechanism to achieve better fire performance was verified by using oxygen bomb calorimeter and thermogravimetrical analysis, exhibiting lower heat of combustion and weight loss. The lower BR and FPS content can extend the survival duration of phosphor-carbonaceous chars. The results provide information for designing vinyl acetate-based coating.
Chih-Shen Chuang, Kuang-Chung Tsai, Te-Hsin Yang, Ming-Kuang Wang, Chun-Han Ko


The potential of silicone-based formulations to enhance wood properties through industrial treatment for outdoor use
2011 - IRG/WP 11-30578
High hygroscopicity is one of the main weaknesses of wood as far as its susceptibility to biodegradation, and specifically to fungal decay. New wood preservation technologies are constantly entering the wood protection market, competing with traditional, biocide-based preservation. Silicones are commercially used as hydrophobic agents on stones and concrete. They belong to the restricted number of products that demonstrate a potential to protect wood through non-biocidal chemistry that increase its hydrophobicity. In this study, small Scots pine sapwood and beech specimens (Pinus sylvestris and Fagus sylvatica) were impregnated with silicone solutions in order to assess these solutions’ ability to increase wood hydrophobicity and resistance to fungal decay. Some wettability tests were also performed to gauge the difference in superficial tension of the tested impregnated wood pieces. The same tests also allowed us to determine the depth of the impregnation. The results of the relative water uptake and water repellent effectiveness tests showed that several silicone formulations significantly reduce the water content of wood by either filling the wooden cavities or impeding water absorption. The potential of using the tested silicone formulations to protect wood against decay fungi for outdoor applications is discussed in this paper.
F Simon, F Marchal, F Pochon, M Kutnik, I Le Bayon


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


Applicability of wood durability testing methods to bio-based building materials
2015 - IRG/WP 15-20561
It is well known that organic materials may be susceptible to attack from a range of fungal organisms and any bio-based material used in locations where there is the possibility of microbiological activity must be expected to be able to withstand or prevent such attack. There are a wide range of test methods and standards in place to test susceptibility although most of these test individual components such as wood or panel material. A wide range of old and new bio-based materials and novel construction techniques are showing an increase in use in new building and in the restoration of old buildings. These materials need to be assessed against microbial activity to determine if they are suitable for use in a particular area. Standard wood decay test methods are widely known and would seem applicable to many of the materials being used – especially where wood based products are used. However, due to their structure certain testing problems can arise. This paper seeks to test a variety of building materials, including sheep’s wool, mineral wool, hemp, wood fibre, cellulose flakes and assess the suitability of the testing regime on these materials. The method selected was the wood panel testing method DD ENV 12038, with some modifications to measure the extent of fungal growth as well as decay. The results show that although there was significant growth of the fungi through test samples only the lignocellulosic materials showed any appreciable decay. It was also noted that for some of the samples the structure of the material e.g. very thick or particulate fill, made the test sub-optimal.
S F Curling, B K Stefanowski, E Mansour, G A Ormondroyd


Performance of bio-based building materials – viewpoints from the first year of COST Action FP1303
2015 - IRG/WP 15-20572
Maintaining and expanding the market potential for bio-based building products in indoor and outdoor construction uses remains a key activity for industries in the forestry and biotechnological sector, particularly in Europe. Whilst there are ongoing activities within IRG for collecting and populating a database on performance on wood, the performance data for many other (i.e. non-wood) "environmental friendly" building materials are lacking as well as suitable comprehensive test methodologies to determine their resistance against mould, stain, and decay. The similarity in terms of decay hazard, resulting response on climatic loads and thus performance of different bio-based building materials has not yet been recognised adequately, and in order to overcome this problem within Europe, COST (Cooperation in Science and Technology) established the Action FP1303 entitled “Performance of biobased building materials”, which from 2013-2017 will provide a platform for networking and scientific exchange between different disciplines, such as material sciences, wood technology, biology, biotechnology, building physics and engineering. Through the activities in this Action, there will be a coordinated effort to put the issue of biodegradability of organic building products on the agenda, combined with consumer demands and preferences. These will help define service life prediction and performance models, will consider aesthetical aspects as well as the functionality of building assemblies. These will ultimately contribute to the control and prevention of any imminent threat to use bio-based building materials, which in turn could severely damage a pan-European low carbon building agenda. This paper outlines some of the activities undertaken within the first year of the Action, and describes some of the planned activities in the coming years.
D Jones


Modelling the performance of bio-based building materials
2016 - IRG/WP 16-20582
The ‘bio-based economy’ represents a growing area of development globally and covers a wide range of building materials including wood and wood-based products. A ‘bio-based’ material is intentionally made from substances derived from living (or once-living) organisms. In this context it means that the materials and products are made from renewable resources, with the criteria that a renewable resource recovers faster than it is drained, in contrast to many mineral and fossil resources. Their successful use in various applications in the building sector requires sufficient performance and reliable performance data are needed. A key instrument for predicting the performance of building materials on the base of test and survey data are models. Performance modelling is therefore an important issue within IRG-WP – in particular addressed within WP 2.1 ‘Prediction of Service Life’ as well as for COST Action FP 1303 ‘Performance of Bio-Based Building Materials’. On occasion of the 47th Annual Meeting of IRG-WP a special session on ‘Modelling’ will be held jointly with COST FP 1303. Exposure, decay, and resistance models related to wood and other bio-based building materials will be presented. Cross links between disciplines are sought and shall be intensified such as between material science, chemistry, building physics, wood and fiber technology, polymer science, biology, mycology, entomology, civil engineering, and architecture. This paper provides an overview about modelling approaches and applications of performance models for design and performance classification. Major challenges related to performance modelling are highlighted and discussed such as quality and availability of data for modelling, the variability of input and output variables, the decay-type specificity of models, and their verification.
C Brischke


Enhancing wood properties through bio-based and non-biocidal co-polyesters
2016 - IRG/WP 16-40740
The commonly used wood preservation treatments are nowadays facing huge environmental issues, as well as increasing public concern. As regards those concerns, legislation tends to regulate the use of biocidal preservation chemicals. Thus, it does appear crucial to provide alternatives to the use of biocides to allow different outdoor uses of wood such as for, posts, decking, and cladding or even for railway sleepers. Heat treatment of wood have been developed to improve its resistance against biodegradation and swelling effect, but the performance of heat treated wood remains limited toward certain wood destroying organisms (soft rots, termites). Moreover, mechanical properties of the thermally modified wood are widely decreased. Our study aims to provide new treatments for wood protection against biodegradation, by impregnation of aqueous solutions of various poly- carboxylic acids or anhydrides (citric acid, succinic anhydride, tartaric acid) and glycerol, followed by in situ heat polymerization. The chemicals mentioned are all bio-based, and allowed for food use (except succinic anhydride) The resistance of the polyesters formed in small Beech (Fagus sylvatica) has been established against leaching, according to the former ENV 1250-2 standard, for 31 hours. The resistance to fungal attack by Coriolus versicolor has been evaluated with a 6 weeks screening tests on the same samples. It has notably been showed the dependence of leaching rate on the heating temperature used for the process. Almost no leaching occurred by heating the samples at 140°C, or at higher temperature. Very low mass losses were obtained through decay resistance tests, showing the performance of the treatments regarding fungal resistance, especially at high curing temperatures. The characterization of the mechanical properties of modified woods shows promising results, by maintaining the resistance of wood in flexion. An Anti-swelling Efficiency and hydrophobicity are also provided by the modification performed.
C L’Hostis, M-F Thévenon, E Fredon, P Gérardin


Assessing the nutrient value of bio-based materials in relation to early fungal growth
2017 - IRG/WP 17-20631
Bio-based materials are gaining importance in the building industry, as the focus on sustainability and life-cycle-assessment has increased dramatically over the last decade. Wood and wood-engineered products as well as insulation materials made from flax, hemp, etc. are hence increasingly used. These materials originate from renewable resources and are often biodegradable, which can cause problems when bio-based materials are exposed to moisture and temperature conditions that are favourable for fungi. Fungal damage is not only an aesthetical issue, but can also severely compromise the structural integrity of a building component. Several standards exists for assessing the inherent resistance of wood species and the efficacy of wood preservatives, and are generally regarded to be sufficient and adequate. However, the existing standards are typically inadequate for the correct qualification of new wood products, whose durability is not enhanced with biocides but by new technologies, such as chemically modified wood (acetylation, furfurylation, etc.), thermally treated wood and also engineered wood products, such as glue-laminated wood, wood-based panels and wood treated with water repellents. In order to know whether the existing standard tests can be applied for bio-based materials other than (impregnated) wood species, certain material characteristics and their influence on fungal resistance as well as the standards’ test methodologies will need to be well understood. Therefore, it is key to unravel the influence of different material characteristics, like the material’s chemical components, its spatial structure and its moisture dynamics, all contributing to the material’s durability or resistance. In this paper, an experimental method is described in which the structure of a material is eliminated, so the chemical component of the material’s resistance can be separated from the other material characteristics. In se, the nutrient value of a material is tested for decay fungi, without the material’s structure and moisture dynamics playing a role.
L De Ligne, J Van den Bulcke, J Baetens, B De Baets, J Van Acker


Liquefied wood polyols: Ecofriendly bio-based preservative for sustainable protection of wood from Termite attack
2018 - IRG/WP 18-10916
The major problems encountered in both indoor and outdoor utilization of wood are biological decay due to termite. The modification of wood with liquefied wood polyols has been found to be effective against termite attack. The liquefaction of wood aims to utilize woody wastes which are being generated during primary and secondary processing of wood in wood based industry. One of promising approaches to utilizing these lignocellulosic wastes is its liquefaction for developing natural products having potential to use as bio based wood preservatives against biological enemies of timber like termite. In this study, woody waste recovered from wood based industry has been liquefied in different liquefying media in defined reaction condition to produce chemically active liquid which is being as wood preservatives for protection of wood from termite. The level of impregnation of preservative in wood was estimated by determining the weight percent gain and the modification was characterized by FTIR and NMR spectroscopy. The efficacy of bio-based preservatives on treated wood against termites was evaluated. The accelerated wood sample were impregnated with liquefied wood polyols and tested as per Indian Standard No.4873:1968 in graveyard for 24 months exposure in field conditions against termite. The periodical observation has been collected and after 24 months accelerated termite test shows promising results both in visual observation and percentage weight loss as compare to initial condition and control sample. Investigation shows that percentage weight loss of accelerated treated wood sample which is ranges from 5- 20% of its initial weight. The increased termite resistance of modified wood indicates liquefied wood polyols which bio- based wood preservatives has a promising potential reagent for modification of wood against natural wood decaying agents. The liquefaction of wood opens up new avenues for utilization of woody waste for development of organic preservative which is environmental friendly and also helps in reducing carbon foot print from the Earth to provides better greener and sustainable world for coming generation.
A Kumar, A John, T S Mehra, A K Pandey, S Singh Chauhan


Simulation and visualization of aesthetic performance of bio-based building skin
2018 - IRG/WP 18-20633
Performance of 120 selected façade materials provided by over 30 industrial and academic partners is under evaluation. The experimental data, acquired during BIO4ever project duration are used for development of the numerical models simulating the material degradation in a function of time and exposure. The weather data calculated according to the ASHRAE 2013 database allows numerical simulation of cumulative radiation and temperature on building facades, situated in 6000 locations all over the world. Dedicated algorithms simulating material deterioration by taking into account specific material characteristics, kinetic and intensity of weathering process as well as specific architectonic details are extensively tested and validated. Accurate service life prediction, service life costing and aesthetical performance models of evaluated bio-based building materials are foreseen as the most important deliverables. Software visualizing bio-materials’ performance will be dedicated for investors, architects, construction engineers, professional builders, suppliers and other relevant parties, including also final customers. It will assist architects/customers to select optimal bio-materials assuring satisfactory performance and high aesthetical valour
J Sandak, A Sandak, P Grossi, M Petrillo


Bio-preservative properties of technical lignins from South African pulp mills: An investigation towards a conceptualized development of natural compound-based wood preservatives
2018 - IRG/WP 18-30724
The depletion of naturally durable timber and the risk posed by some of the conventional wood preservatives to human health and the environment continue to drive research efforts towards developing new formulations that are benign. Furthermore, the global concept of environmental sustainability aims at optimal use of resources and to comprehensively include conversion of waste to value added products. In view of these, it becomes a point of interest to utilize compounds from waste streams such as technical lignin obtainable from pulp black liquor by-products in the development of formulations to be used either as a sole material or component of wood preservatives. The incorporation of lignin into wood preservative formulations have only been previously achieved by means of a two-stage process involving fixation with metal salts, lignosulphonate copolymerisation and use of metal ammonia complexes as impregnants. However, the overall limitation of these processes is the inadaptability to industrial practice, owing to time factors, high cost of copolymerized lignins, and inability to use certain lignins. In view of the increasing global interest in green economy and environmental sustainability, the prospect of developing a natural compound-based wood preservative formulation using technical lignin alongside other natural compounds from biomaterial waste becomes invaluable. It is anticipated that the proposed preservative formulation would be suitable for a single-stage process adaptable to industrial practice. The suitability of lignin as a component in the development of the natural compound-based wood preservative depends on its properties. These properties vary with origin and isolation method. To this end, this study will investigate the bio preservative properties of technical lignin recovered from pulp black liquors (PBLs) obtained from different biomass origins and pulping processes commercially employed in the South African pulp industry.
A Alade, L Tyhoda, M Meincken


Liquefied wood polyols: a bio-based preservative for protection of wood from fungal decay
2018 - IRG/WP 18-30725
The liquefaction of wood is one of promising approaches in utilization of woody waste which is generated during primary and secondary processing of wood and liquefied wood having various application including bio-based preservatives. The biological degradation of wood due to fungi is the major problem encountered in indoor and outdoor utilization of wood. In this study, woody waste recovered from wood based industry was liquefied in phenol, glycerol and polyethylene glycol as liquefying media under defined reaction condition to produce chemically active liquid. These liquefied woods were used as preservatives and its efficacy were evaluated after impregnation of wood against fungi. The level of impregnation of preservative in wood was estimated by the weight percent gain after impregnation and the changes were characterized by FTIR and NMR spectroscopy. The melia wood samples have been impregnated with liquefied wood and untreated wood sample were also exposed to a brown rot (Polyporus meliae and Oligoporus placentus) and a white rot (Trametes hirsuta (Wulf. Ex Fr.) and Trametes versicolor (L. Ex Fr.) fungus for 16 weeks under laboratory conditions as per IS: 4873 (Part I), 2008. Investigation indicated that phenolated wood inhibited fungal growth in the wood. The fungicidal traits of phenolated wood showed higher antifungal efficacy against both white rot and brown rot of wood whereas wood samples impregnated with liquefied wood in glycerol and polyethylene glycol shows insignificant effects on growth of fungus and is similar infested as to control samples. The increased fungal resistance of phenolated wood indicates liquefied wood polyols has a promising potential for treatment of wood against natural wood decaying agents. The liquefaction of wood opens up new avenues for utilization of woody waste for development of organic preservative which is environmental friendly and also provides greener and sustainable option to the world for present and coming generation.
A Kumar, G Vijaylakshmi, S Singh Chauhan


Long service life or cascading? The environmental impact of maintenance of wood-based materials for building envelope and their recycling options
2018 - IRG/WP 18-50336
A major restraint in choosing bio-based materials (i.e. wood-based) for external use, is the lack of confidence that architects, designers and customers have toward these materials. In particular, the limit state of bio-based materials, which defines the frequency of maintenance operations, might be reached earlier for wood than for other materials (i.e. concrete). On the other hand, resource and energy scarcity together with increasing concern for climate change consequences are raising the demand for competitive bio-based materials in the built environment as substitutes for other energy-intensive materials. Therefore, novel and traditional protective treatments are used to improve the performance of woody materials for outdoor use. Nonetheless, the environmental and economic burden of such treatments is often unknown. The number of LCA (life cycle assessment) studies on the topic is low, with geographically sparse data and non-uniform assessment protocols. This study provides a novel approach to assess the in-service performance, maintenance requirements and end-of-service-life options for over one hundred bio-based materials for façades. The protection techniques of the materials under examination include: chemical modification, thermal treatment, impregnation, hybrid treatments, and surface treatments (bio-film, coating and nanocoating). Natural, untreated wood and composite materials such as wood-plastic composites are included as well. The in-service environmental performance is analysed by considering the amount of material, energy, water and waste that are used and/or produced to maintain one square meter of façade. The options for end-of-service-life include: panel manufacturing, pelletizing, animal bedding, liquefaction, insect conversion, fungal conversion, combustion, incineration, gasification and pyrolysis, anaerobic digestion, fermentation, composting and landfilling. For each material group, the possibility for cascading use is assessed. The overall goal is to increase the confidence in bio-based building materials by tackling environmental issues related to wood modification processes.
M Petrillo, J Sandak, P Grossi, A Kutnar, A


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