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The problem was to determine the effectiveness of using polyethylene glycol 1000 in the treatment of green wood for the purpose of forming projects made of wood veneer and of simple design for use in junior high or high school woodworking classes. The purpose of this study was to seek answers to the following questions. 1. Is polyethylene glycol 1000 an effective stabilizing agent for green wood veneer that can be used in school woodworking classes? 2. Can green wood veneer treated with polyethylene glycol 1000 be bent to form simple woodwork projects? 3. Can green wood veneer treated with polyethylene glycol 1000 be successfully used in junior high and high school woodworking classes? 4. What length of treatment time is best for green wood veneer that is to be used to form simple bent wood projects? 5. Is one-fourth inch thickness suitable for green wood veneer that is to be treated with polyethylene glycol 1000 and used to form simple bent wood projects?

La modification thermo-chimique est un procédé qui consiste à modifier la matière à cœur, avec pour objectif d’améliorer les propriétés du bois, en particulier la résistance fongique. Pour ce faire, conférer au bois un équilibre hygroscopique inférieur à la limite basse de développement des champignons est une approche qui permet en sus de limiter les variations dimensionnelles dues à l’humidité de l’air. Limiter les variations dimensionnelles augmente logiquement la durabilité des assemblages et des revêtements de surface, ce qui améliore encore les performances du matériau. Les constituants du bois possèdent des groupements hydroxyles qui rendent le matériau hydrophile. Les modifications thermochimiques envisagées dans ces travaux de recherche consistent principalement à limiter l’accès à ces groupements et/ou à réduire leur nombre, par imprégnation de monomères/oligomères bio-sourcés (oligomères d’acide lactique (OLA) ou de poly(butylène succinate) (OBS)) suivie de leur polymérisation in situ par traitement thermique. Le comportement hygroscopique du matériau, la persistance des oligomères dans le bois et la résistance biologique du bois traité sont les critères de sélection des traitements. Les traitements retenus conduisent à des matériaux ayant une meilleure stabilité dimensionnelle et une meilleure résistance biologique. Les potentielles applications de ces matériaux ont été évaluées après caractérisation des propriétés mécaniques, de l’adhésion des revêtements de surface et de la capacité de collage du bois traité / Wood thermo-chemical modification process consists of permanent enhancement of wood properties in the core of the material. By decreasing wood equilibrium moisture content below the limit of fungi development, one could in addition reduce the dimensional variations due to humidity. A better dimensional stability of wood would be beneficial to durability of assemblies and surface coatings, further improving the performance of the material. Hydroxyl groups from wood polymers are responsible for the material hydrophilicity. The thermochemical modifications considered in this work mainly consist in limiting the access to these groups and / or reducing their number, by impregnation of bio-based monomers / oligomers (oligomers of lactic acid (OLA) or oligomers of butylene succinate (OBS)) followed by their in situ polymerisation by heat treatment. The hygroscopic behaviour of the material, the persistence of oligomers in the wood and the biological resistance of the treated wood are the criteria for the selection of treatments. The selected treatments lead to materials with enhanced dimensional stability and biological resistance. The potential applications of these materials have been evaluated after characterisation of mechanical properties, adhesion of the surface coatings and bonding capacity of the treated wood

The primary reason for incorporating pigments into plastic materials is to impart the desired colour to finished articles. Some pigments however, may interact with the polymer leading to unexpected deleterious effects. Organic pigments, especially phthalocyanines, are favourable for their brilliant shade but are also well known for causing part distortion or warpage. This causes problems in parts which require good dimensional stability such as crates, containers, trays, caps and closures. Despite that, there are not many published studies on the root cause and mechanism of warpage induced by the pigment. Hence, the objective of this research is to study the influence of such pigments on the dimensional stability, crystallisation behaviour and morphology of polyethylenes in order to have a better understanding on the mechanism of warpage, which could possibly lead to a solution in overcoming this problem.

Cementitious materials with strain-hardening property and high tensile ductility are promising materials on account of their mechanical and durability performances. These materials require special ingredients which make it costly to be used in conventional constructions. Hence, potential applications of Engineered Cementitious Composites (ECC) generally focus on layered systems or repairs which require the use of ECC together with another material. For it to be used especially as a repair material, it should have sufficient dimensional compatibility for preventing restrained shrinkage cracking. In this thesis, a strain-hardening fiberreinforced cementitious composite, named Engineered Cementitious Composites, was produced with local ingredients and their mechanical performance, dimensional stability properties were investigated. For investigating the effect of materials and mix proportions on mechanical properties, compressive strength, flexural strength with mid-span beam deflections and matrix fracture toughness tests were conducted. For determining the dimensional compatibility properties, autogenous, drying and restrained shrinkage tests were conducted along with tensile creep tests. As a result it was shown that, mechanical and dimensional stability properties are affected by the ingredients and mix proportions. It was shown that especially autogenous shrinkage of mixtures was relatively high which can cause early age cracking. In order to mitigate the adverse effect of autogenous shrinkage, the effect of pre-soaked expanded perlite aggregate replacement on mechanical, shrinkage and dimensional compatibility properties was investigated. As a result it was found out that autogenous shrinkage can be mitigated by the use of pre-soaked expanded perlite aggregate replacement.

Despite many excellent properties of wood which make it suitable for many applications, it suffers from a number of disadvantages limiting its use. For instance, modification is needed to reduce water sorption and to improve decay resistance, dimensional stability and weathering performance. In addition, wood/liquid interaction such as water wettability on wood plays an important role in design and characteristics of many processes and phenomena such as adhesion, coating, waterproofing, wood chemical modification, and weathering. This thesis focuses on enhancing the understanding of wetting of wood, with emphasis on modified wood. The influence of surface chemical composition of wood and its microstructural characteristics on wetting and swelling properties has also been studied. A multicycle Wilhelmy plate technique has been developed to evaluate wetting properties of porous materials, such as wood, in which the samples were subjected to repeated immersions and withdrawals in a swelling liquid (water) and in a non-swelling liquid (octane). This method was utilized to dynamically investigate contact angle, sorption and swelling properties, as well as dimensional stability of unmodified, chemically and surface modified wood samples. Scots pine sapwood and heartwood samples were utilized to establish the principles of the technique. Acetylated and furfurylated wood samples with different level of modification were thereafter examined utilizing the developed technique for wetting measurements. A perimeter model based on a linear combination of the measured force and final change in sample perimeter was suggested to evaluate the dynamic dimensional stability of wood veneers. The feasibility of this method for studying dynamic wettability was investigated by measuring the changes of advancing and receding contact angles over repeated cycles on surface modified wood samples, created by combining liquid flame spray and plasma polymerisation methods. X-ray photoelectron spectroscopy (XPS) and X-ray computed tomography (XCT) were employed to study the surface chemical composition and microstructural properties of the samples, respectively. Three different kinetic regimes were observed in the wetting measurements: i) fast wetting and spreading of the liquid on the wood surface, ii) void filling and wicking and iii) swelling, which was the slowest of the three. The multicycle Wilhelmy plate method was found to be suitable for studying liquid penetration, sorption, and dimensional stability of swelling materials. The results demonstrate that the wetting properties of wood are highly affected by surface chemistry and microstructure. It was shown that using both swelling and non-swelling liquids in wetting measurements allow to distinguish between capillary liquid uptake and swelling. Based on this, for chemically modified samples, it was demonstrated that acetylation mostly reduces swelling, while furfurylation reduces both swelling and capillary uptake. This is in line with the microstructural study with X-ray computed tomography where a significant change in the porosity was found as a result of furfurylation, conversely acetylation left the total porosity values unchanged. Wetting results for hydrophobised wood samples demonstrate that the multi-scale roughness obtained by combination of nanoparticle coating and plasma polymerization increased both the hydrophobicity and the forced wetting durability compared to the micro-scale roughness found on wood modified with plasma polymerisation alone. / <p>QC 20151029</p> / Sustainable wood modification

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The genera Corymbia and Eucalyptus although used by industries face limitations such as high levels of growth stresses, drying problems and high shrinkage. Thus, methods such as heat treatment are studied to improve these properties. The objective of this research was to study the effect of heat treatment on physical and mechanical properties of wood of Corymbia citriodora and Eucalyptus saligna. From each species 3 trees were sampled, with approximately 40 years of age, which were sectioned with the first two logs in lengths of 3 meters each. The heat treatment was applied with final temperature of 140 º C, 160 º C and 180 º C for 2.5 hours using an oven with forced air circulation. To determine the physical and mechanical properties there were used the procedures of ASTM D 143-94 (ASTM, 2000) and NBR 7190 (ABNT, 1997). The physical properties analyzed were the equilibrium moisture content, weight reduction, loss of density, swelling coefficient, total (linear and volumetric) and coefficient of anisotropy. Mechanical properties evaluated were modulus of elasticity (MOE) and rupture (MOR) in bending, compression parallel to grain and impact resistance. The results, in general, demonstrated for all physical properties that the heat treatment is effective in reducing the hygroscopicity and increasing dimensional stability of both species, with best results in treatments with higher temperatures. The results of the mechanical properties have shown that impact resistance for both species was reduced compared to control in all treatments. The test results static bending, for both species, increased in temperature of 140 ° C and decreased at temperatures of 160 º C and 180 º C. Compression parallel to the grain in wood of Corymbia citriodora increased with heat treatment at temperature of 140 ° C and presented a reduction at other temperatures. The wood of Eucalyptus saligna, the evaluation of compression parallel to the grain, presented a decrease in strength with increasing temperature. In accordance with the results of the study the thermally treated material can be used in places where humidity is higher, however it is not suitable for structural use, because its strength is reduced with increasing temperature. / Os gêneros de Corymbia e Eucalyptus apesar de utilizados pelas indústrias enfrentam limitações como altos níveis de tensões de crescimento, problemas de secagem e alta retratibilidade. Dessa forma, métodos como o tratamento térmico são estudados para melhorar essas propriedades. O objetivo desta pesquisa foi estudar o efeito do tratamento térmico nas propriedades físicas e mecânicas da madeira de Corymbia citriodora e Eucalyptus saligna. Foram amostradas 3 árvores de cada espécie, com aproximadamente 40 anos de idade, as quais foram seccionadas as duas primeiras toras com comprimento de 3 metros cada. Para o tratamento térmico foram aplicadas temperaturas finais de 140ºC, 160ºC e 180ºC, durante 2,5 horas, utilizando estufa com circulação de ar forçada. Para a determinação das propriedades físicas e mecânicas foram utilizados os procedimentos estabelecidos nas normas ASTM D 143-94 (ASTM, 2000) e NBR 7190 (ABNT, 1997). As propriedades físicas avaliadas foram umidade de equilíbrio, redução de massa, perda de massa específica, coeficiente de inchamento total (linear e o volumétrico) e coeficiente de anisotropia. As avaliações de resistência mecânica foram realizadas pelo módulo de elasticidade (MOE) e ruptura (MOR) em flexão estática, compressão paralela às fibras e resistência máxima ao impacto. Os resultados, em linhas gerais, demonstraram para todas as propriedades físicas avaliadas que o tratamento térmico é eficiente na redução da higroscopicidade e aumento da estabilidade dimensional de ambas as espécies, com melhores resultados, nos tratamentos com maiores temperaturas. Os resultados das propriedades mecânicas demonstraram que a máxima resistência ao impacto, para ambas as espécies, foi reduzida em relação à testemunha em todos os tratamentos. Os resultados do ensaio de flexão estática, para as duas espécies, teve um aumento na temperatura de 140ºC e diminuiu nas temperaturas de 160ºC e 180ºC. Para a compressão paralela as fibras a espécie Corymbia citriodora teve aumento na temperatura de 140ºC, reduzindo nas demais temperaturas. A espécie de Eucalyptus saligna, na avaliação da compressão paralela as fibras, reduziu com o aumento da temperatura. De acordo, com os resultados do estudo o material tratado termicamente pode ser utilizado em locais com umidade mais elevadas, entretanto não sendo indicado para uso estrutural, pois sua resistência é reduzida com o aumento da temperatura.

Den textila industrin är en av världens största industrier, en resurskrävande industri med komplicerade och förorenande processer. Processer som innefattar flera olika steg, från råmaterial till färdig produkt. Detta gäller för alla textila produkter vare sig det handlar om klädesplagg inom fast fashion, eller teknisk textila produkter. Varje steg i processen har en inverkan på miljön och kan även ske på olika geografiska platser runt om i världen. Fast fashion-industrin karaktäriseras av korta produktlivslängder, hög instabilitet och låga priser, vilket direkt kopplas till negativ miljöpåverkan. Enligt konsumenter är kvaliteten på klädesplagg idag bristfällig och det är en stor anledning till varför många använder sina plagg endast ett fåtal gånger. Denna studie undersöker om och hur man kan identifiera livslängden på fyra olika grövre trikåkvaliteter, samt undersöka om förbättringsförslag kan ges för att öka livslängden på dessa. Undersökningen har innefattat kvantitativa metoder genom en enkätstudie där 100 personer deltagit, samt standardiserade testmetoder. I enkätundersökningen fick respondenterna redogöra kvalitetsbrister och användarbeteende. Detta har fungerat som riktlinjer till en metodplan för att simulera användning. Enkätens resultat visade att störst kvalitetsbrister och anledning till att plagg slutar användas främst berodde på grund av noppbildning, slitage genom nötning och dimensionsförändringar. Därmed har metodval för standardiserade tester valts inom dessa parametrar. Detta med 15 tvättcykler mellan testningarna för att simulera två års användning. Mätningar har även jämförts mot kvaliteternas kravspecifikation. Testernas resultat visade att samtliga kvaliteter har en bra beständighet mot nötning, i förhållande till dess kravspecifikation. Samma gällde för resultaten inom dimensionsstabilitet, dock med mycket varierande dimensionsförändringar på olika områden. Vid test av benägenhet till att bilda noppor, klarade endast hälften av kvaliteterna kravspecifikationens villkor. Dessa resultat gäller både innan och efter 15 tvättcykler. Förbättringsförslag för en förhöjd kvalitetsstandard, därmed förlängd livslängd, var svårt bestämma utifrån den information till kvaliteterna som fanns att tillgå. Resultat visade att fibertyp, fibertjocklek, spinnmetod, garnkonstruktion, bindning, masklängd samt delning på stickmaskin är alla parametrar som avgör slutproduktens kvalitet. Olika tekniker för samtliga parametrar medför olika egenskaper som bestämmer slutkvaliteten. I brist på information om värden för nämnda parametrar var förbättringsförslag ej möjliga att bestämma. / The textile industry is one of the world's largest industries, a resource-intensive industry with complicated and polluting processes. Processes that include several different steps, from raw material to final product. Which applies for all textile products, whether it is clothing in fast fashion or other textile products. Each step in the process has an impact on the environment and many of them take place indifferent geographical locations around the world. The fast-fashion industry is characterized by short product lifetimes, high instability, and lower prices, which directly links to negative environmental impacts. According to consumers, the quality of today's clothing has a major deficiency and is a major reason why many people only use their garments a few times before discarding them. This study examines how to identify the lifespan of four different coarser knitted sweaters, but also investigate if it is possible to provide improvement suggestions on how to increase the longevity. The project includes quantitative methods through a survey which has been done by 100 people, and standardized tests. Within the survey the respondents were asked to report quality deficiencies and care behavior. Which has served as guidelines for choice of methods to simulate use of clothing. The results of the survey showed that greatest quality deficiencies and reasons why garments stop being used were mainly due to pilling formation, wear due to abrasion and dimensional changes. Thus, choices of methods for standardized tests were chosen to test within these parameters. This with 15 wash cycles between tests to simulate two years of use. Results have also been compared to the garment requirement specifications. The test results showed that all garment samples had good resistance to abrasion, in relation to the requirement specifications. The same applies to the results within the dimensional stability, however, dimensional changes vary a lot in different areas. The results apply both before and after 15 wash cycles. Suggestions for improvement for an increased quality standard, for increased longevity, were difficult to determine based on the limited information provided regarding the garments. Results showed that fiber type, fiber thickness, spinning method, yarn construction, knit structure, loop size and gauge of the knitting machine are all parameters that influence the quality of the final product. Different techniques for all parameters result in different properties that determine the final quality and the longevity for the product. The lack of specific information needed for the parameters mentioned, suggestions for improvement were not possible to determine.

This work focused on decay and dimensional stability of southern pine lumber and environmental issues associated with emissions released during kiln drying of southern pine. In one study decking boards were treated with a 3% resin acid solution to increase the dimensional stability. The boards were placed on a roof and weathered for two years. The increased water repellency reduced moisture gain following summer rainstorms by one-third compared to untreated matched samples, this significantly reduced splitting by half and cupping by one-third. In one study decking boards from matched samples were weathered for two years in the roof setup described above, and in a fungal ground proximity test. The ground proximity samples had slightly more decay than the roof samples. Correlation between decay ratings for the matched samples was 37%, suggesting above-ground decay susceptibility is dependent on the macro- and micro-environment. Decay in roof exposure was modeled based on moisture content factors, whereas decay in ground proximity was modeled by the resin and fatty acids. One study tested pole sections with varying amounts of sapwood, heartwood, and knots dried in a pilot-scale kiln. A sample of the kiln exhaust was measured for volatile organic compounds. Emissions from poles were similar to clear lumber. Emissions from heartwood poles were less than for heartwood lumber, perhaps due to the poles’ sapwood band. The final study was conducted with clear and knotty lumber kiln dried to below 8% moisture content using three kiln schedules. Wood dried to this lower moisture content is used in interior applications or exported. During drying, a sample of the kiln exhaust was analyzed for total VOCs, and a sample of the kiln exhaust was collected and analyzed for hazardous air pollutants via gas chromatography and spectrophotometry. For all three kiln schedules, mills would reach 10 tons of methanol and thus must comply with maximum achievable control technology standards before reaching 25 tons of methanol, formaldehyde, acetaldehyde, acrolein, and propionaldehyde.

Actuellement l’industrie montre un intérêt croissant pour le développement de matériaux composites intégrant des constituants issus de la biomasse. Dans ce contexte, différentes fibres lignocellulosiques sont envisageables en tant qu'alternative aux fibres de verre pour le renforcement des matrices thermoplastiques ou thermodurcissables. En effet, les fibres végétales présentent des caractéristiques physiques intéressantes, telles qu’une faible densité et de bonnes propriétés mécaniques spécifiques, associées à un impact environnemental réduit, leur permettant ainsi de répondre à des problématiques sociétales. Cependant, la forte variabilité naturelle des dimensions et des propriétés mécaniques des fibres végétales rend nécessaire le développement de méthodologies de caractérisation spécifiques permettant en particulier de quantifier leur forte sensibilité à l’humidité. La première partie de cette thèse présente la mise en place d'une stratégie de caractérisation des dimensions transversales des fibres végétales s’appuyant sur une technique de balayage laser associée à une modélisation géométrique fiabilisée. Cette méthodologie est validée sur la base d’une étude dimensionnelle de faisceaux de fibres issus de différentes espèces végétales morphologiquement contrastées (lin, chanvre, ortie, sisal, palmier). La modélisation proposée permet de réduire de manière significative la dispersion des propriétés mécaniques des faisceaux de fibres étudiés. Dans une seconde partie, l’effet de l’humidité sur les variations dimensionnelles et le comportement mécanique des fibres végétales est quantifié. Les résultats révèlent des phénomènes de gonflement et de plastification des parois cellulaires différenciés selon la composition biochimique et la microstructure des différentes espèces végétales. / Currently, the industry is showing a growing interest in the development of composite materials incorporating components derived from biomass. In this context, various plant species can be used as reinforcement of thermoplastic and thermoset, in substitution to glass fibres. Indeed, natural fibres have interesting physical characteristics, such as their low density and good specific mechanical properties associated with the fact that they reduce environmental impacts answering to societal problems. However, the high natural variability of their dimensions and mechanical properties make it necessary to develop specific characterization methods particularly to quantify their high humidity sensitivity. The first part of this study presents the development of characterization methodologies of natural fibres transverse dimensions based on an automated laser scanning technique associated with a reliable geometric modeling and validated on plant species with contrasted morphologies (flax, hemp, sisal, nettle, and palm). The proposed modeling makes it possible to drastically reduce the mechanical properties dispersion of the studied fibre bundles. In a second part the effect of humidity conditions on the dimensional variations and the mechanical behavior of natural fibres are quantified. The results revealed contrasted swelling and plasticization behaviour, depending on biochemical composition and microstructure of plant species.