Wood Polymer Composites are a new group of hybrid materials, which combine the advantages of synthetic polymers such as polyolefines and natural polymers such as wood; whereas the synthetic polymer is used as matrix material and the wood as reinforcement material or filler. As matrix material, principally every thermoplastic polymer with a processing temperature below 200°C can be used due to the temperature sensivity of wood. Wood Polymer Composites are processed typically with processing technologies from the plastic industry such as extrusion and injection molding. The present study was conducted to explore the possibility of wood particle modification with different types of silanes. It was the aim to contribute the silanes as compatibilizers or coupling agent and therefore improve the mechanical properties and the resistance against water. Norway spruce (Picea abies) as representative wood species was used in three different particle types. The size distribution for the wood particles ranges from 70-2500 µm. Four commercial available silanes with various functional groups (amino, di-amino, alkyl) were used as modification agents. The concentrations varied between 1.5%, 3.0%, 4.5% and 7.5%. As reference system commonly used maleated acid anhydride based coupling agents were used. The pre-treated wood particles were compounded via extrusion with polypropylene and samples were produced via injection and compression molding. The following properties were tested; tensile, bending, and impact strength, water uptake (cold and boiling water test), descent rate, weathering tests and durability test against basidiomycetes. SEM-EDX investigations proved the presence of silane either in the cell wall structure, or on the wood particle surface. Due to the structure and the functionality of the silanes it was expected that the silane treated wood particles are able to improve the mechanical properties. It was shown that the silanes had no significant effect as compatibilizer or coupling agent. The mechanical properties strongly increase with the usage of coupling agent. Both coupling agents were based on maleic acid anhydride grafted on a polymer backbone, whereas Type I reaches an optimum regarding the mechanical properties at 3%, the coupling agent Type II still improves the mechanical properties up to a ratio of 4.5% with no clear optimum. The silane pretreatment influences the improvement not significantly, compare to the improvement caused by the coupling agent. The used wood particles showed mechanical degradation during the compounding process. The biggest degradation was monitored for the wood particles of Lignocel® Type 9. Due to its fine structure it can be assumed that the Arbocel® C100 wood particles consist of only cell wall fragments of the wooden cell wall, which express a better resistance against mechanical destruction during the process. The Wood Polymer Composites showed a lower decay rate compared to solid wood. The moisture content within the Wood Polymer Composite samples ranges at the low optimum level for fungi attack and were not significantly improved by an accelerated wetting before the test. The core remains relatively dry. The main protection seems to come from the encapsulation by the polymer. The weathered Wood Polymer Composite samples showed a strong color change within a relatively short period of exposure. The color changed independently from the silane type or the silane ratio. Also an increase of cracks and gaps on the sample surface was observed compared to the unexposed sample and the pure polymer reference.

Based on the results of two bioenergy research initiatives in Germany, this reference examines the sustainable management of wood biomass in rural areas. The large number of participating organizations and research institutes ensures a balanced and unbiased view on the potentials and risks is presented, taking into account economic, ecological, and social aspects. Most of the results reported are available here for the first time in English and have been collated in central Europe, but are equally applicable to other temperate regions. They highlight best practices for enhancing dendromass potential and productivity, while discussing the implications on rural economies and ecosystems.

Wood-polymer composites (WPC) are materials in which wood is impregnated with monomers that are then polymerised in the wood to tailor the material for special applications. The resulting properties of these materials, from lightness and enhanced mechanical properties to greater sustainability, has meant a growing number of applications in such areas as building, construction and automotive engineering. This important book reviews the manufacture of wood-polymer composites, how their properties can be assessed and improved and their range of uses.After an introductory chapter, the book reviews key aspects of manufacture, including raw materials, manufacturing technologies and interactions between wood and synthetic polymers. Building on this foundation, the following group of chapters discusses mechanical and other properties such as durability, creep behaviour and processing performance. The book concludes by looking at orientated wood-polymer composites, wood-polymer composite foams, at ways of assessing performance and at the range of current and future applications.With its distinguished editors and international team of contributors, Wood-polymer composites is a valuable reference for all those using and studying these important materials. Provides a comprehensive survey of major new developments in wood-polymer composites Reviews the key aspects of manufacture, including raw materials and manufacturing technologies Discusses properties such as durability, creep behaviour and processing performance

Abstract The study investigated the influences of wood modification on the properties of Polyvinyl chloride (PVC) based Wood Polymer Composites (WPC). Various ethanolamines, L-arginine, pre-hydrolyzed and monomeric aminosilane, melamine and acetic anhydride treatment were used to improve the adhesion between wood and polymer as well as water absorption behavior and resistance to basidiomycetes. Amine based treatments were chosen to change the nature of wood from acidic to basic in order to increase the compatibility with the acidic polymer. Treated and untreated wood flour, PVC and additives were dry blended in a mixer. The dry blend was compounded to granulate by counter-rotating twin screw extrusion and compression moulded into panels using a hydraulic press. Elemental analysis (nitrogen content) via gas chromatography showed expected fixation of aminosilane and melamine treatment. The nitrogen fixation of ethanolamine and L-arginine treated material were obviously reduced, whereas the amount and reactivity of the aminogroups influenced the fixation behavior. With increasing content of amino-groups and reactivity, the fixation was improved. Fourier transform infrared (FTIR) analyses revealed interactions between monoethanolamine and cell wall components. The amine based treatments changed the nature of wood from acidic to basic. An improvement of the interphase was detected via mechanical property testing. Tensile strength, elongation at break and unnotched impact strength of the composite were obviously increased by Larginine, ethanolamine and aminosilane treatments. It has to be considered that amine based treatments (monoethanolamine in this study) led to reduced thermal stability of the composite. Thermogravimetric analysis showed a decrease of onset temperature with increasing monoethanolamine content. Water repellence of the composite was improved by melamine, pre-hydrolyzed aminosilane and acetic acid treatment. Treated and untreated composites revealed high resistance against basidiomycetes. Due to the low initial moisture content and low weight loss of untreated and treated composites, no effect of the various modifications was distinguished. In general it is possible to treat/modify PVC/wood flour composites with used processing and chemical agents. Amine based treatments indicate an improved adhesion between wood and polymer and can be used as coupling agents. Acetic anhydride, melamine and prehydrolyzed aminosilane treatments improved water absorption behavior. Zusammenfassung In der vorliegenden Arbeit wurden die Auswirkungen verschiedener Holzmodifizierungen auf die Eigenschaften von Polyvinylchlorid (PVC) basierten Holz-Kunststoff Kompositen untersucht. Der Fokus lag dabei auf Verbesserung der Interphase zwischen Holz und Polymer, sowie einer Reduktion der Wasseraufnahme und einer Erhöhung der biologischen Dauerhaftigkeit des Komposits. Als Modifizierungschemikalien wurden Ethanolamine (Mono-, Di-, Triethanolamin), L-Arginin, Aminosilane, Melamin und Essigsäureanhydrid verwendet. Die eingesetzten Aminosilane unterschieden sich hinsichtlich ihrer Molekülgröße vor der Behandlung (Monomer, vor-hydrolisiert). Amin basierte Chemikalien wurden ausgewählt, um die Ladungseigenschaften des Holzes zu verändern. Eine bessere Kompatibilität zwischen dem sauren Polymer und der basisch modifizierten Holzoberfläche sollte dementsprechend erreicht werden. Das behandelte und unbehandelte Holzmehl wurde mit dem PVC und ausgewählten Additiven im Heiz-Kühl Mischer zu einem Trockengemisch verarbeitet. Das Trockengemisch wurde in einem gegenläufigen Doppelschneckenextruder granuliert und anschließend im Heißpressverfahren zu Platten gepresst. Mittels einer gaschromatischen Elementaranalyse wurde der Stickstoffgehalt der Holzmehlproben ermittelt, um Aussagen über die Fixierung der jeweiligen Chemikalie treffen zu können. Aminosilan und Melamin behandelte Proben zeigten die erwarteten Fixierungswerte. Die Stickstofffixierung der Ethanolamin und L-Arginin behandelten Proben war im Vergleich dazu deutlich reduziert. Allerdings wurde beobachtet, dass mit steigender Aminogruppenanzahl und Reaktivität auch die Fixierung zunahm. In Fourier Transform Infrarot (FTIR) Analysen wurden Interaktionen zwischen Monoethanolamin und den chemischen Zellwandkomponenten beobachtet. Zudem führte die Behandlung mit Aminosilanen, Ethanolaminen und dem L-Arginin zu einer pH-Wert Verschiebung. Die behandelten Proben besaßen basische Eigenschaften. Eine Verbesserung der Interphase wurde nach der Durchführung mechanischer Eigenschaftsprüfungen gemessen. Die Zugfestigkeit, Bruchdehnung und Schlagzähigkeit der Komposite wurden deutlich erhöht, wenn das Holzmehl zuvor mit Aminosilanen, Ethanolaminen oder L-Arginin behandelt wurde. Allerdings wurde die thermische Stabilität des Komposits durch die Behandlung (Monoethanolamin) herabgesetzt. Thermogravimetrische Analysen (TGA) zeigten eine reduzierte Zersetzungstemperatur mit steigendem Monoethanolamingehalt. Die Behandlung mit Essigsäureanhydrid und Melamin führte zu einer Verringerung der Wasseraufnahmegeschwindigkeit, sowie zu einer Reduzierung der maximalen Materialfeuchte. Bezüglich der verwendeten Aminosilane wurde nur bei der vor-hydrolisierten Variante eine Verbesserung des Wasseraufnahmeverhaltens beobachtet. Alle Komposite wiesen eine hohe Resistenz gegenüber Basidiomyceten auf. Aufgrund der niedrigen Feuchtegehalte vor Versuchsbeginn und den geringen Masseverlusten wurden keine Effekte der jeweiligen Behandlung festgesellt. Prinzipiell ist es möglich mit den verwendeten Chemikalien und Verarbeitungsverfahren Modifizierungen an PVC basierten Holz-Kunststoff Kompositen durchzuführen. Amin basierte Behandlungen zeigten eine erhöhte Kompatibilität mit dem Polymer, womit sie grundsätzlich als Haftvermittler eingesetzt werden können. Zudem wurde das Wasseraufnahmeverhalten der Komposite durch die Behandlung mit Essigsäureanhydrid, Melamin und vorhydrolisiertem Aminosilan positiv beeinflusst.

This book comprehensively covers the different topics of wood polymer composite materials mainly synthesis methods for the composite materials, various characterization techniques to study the superior properties and insights on potential advanced applications. It also discusses the chemistry, fabrication process, properties, applications, recycling and life cycle assessment of wood polymer composites. This is a useful reference source for both engineers and researchers working in composite materials science as well as the students attending materials science, physics, chemistry and engineering courses.

At present, the use of polymer composites filled with wood (WPC) is becoming increasingly popular. In particular, flooring of terraced premises, siding, decorative fences, fence systems, steps, universal profiles, among others are made from WPC. In 1977, the first enterprise for the production of WPC appeared in Sweden. The first experience was not very successful – the demand turned out to be low, and the wear of technological equipment was very high. Therefore, developments in this field were resumed only in the 1990s and continue to this day. This book describes the basic physical and mechanical properties of modern WPC, such as tensile and compression strength, and hardness. Also, the influence of climatic factors on the performance properties of products from WPC is described, while the thermal and rheological properties of WPC materials are considered, which directly affect the consumer characteristics of the products. The book contains theoretical developments related to the prediction of the mechanical and thermal properties of polymers and composites. The Van der Waals volume and the energy of the intermolecular interaction are estimated. This book will be of interest to representatives of the WPC market, designers, and architects, as well as technology engineers, students and post-graduate students of higher educational institutions in the fields of chemistry and physics of composite polymer materials.