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The contribution describes preparation of the so-called "green composites" in which polycaprolactone serves as matrix and the reinforcement consists of nano-and micro-dust of selected exotic woods, i.e., teak, garapa and massaranduba. The composites were processed into nanofibers (by electrostatic spinning technology Nanospider) and their thermal stability was tested with regard to the type of wood. FTIR and SEM analyses were performed to determine structure and morphology of the surface, as well as strength characteristics.
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The paper describes preparation of products by joint oxidation of graphite and fullerene C60 and it evaluates their properties and structure depending on their mutual weight relations. The characteristics of the products include their ability to form foils, thermal stability (TGA, DSC), identification of functional groups (FT-IR) and morphology (microscopic analysis) of the prepared foils. We have discussed differences in properties of the products and the effect of fullerene quantity on the structure. We have also analyzed effects of the method of foil preparation on its quality, the possibility to combine the foil with nanofibers and the ability to create lamellar fibers by freeze drying. Keywords--graphite, fullerene C60, foil, nanofibers, oxidation, freeze drying, lamellar fibers
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As part of an ongoing research on biodegradable composites, which can be aptly termed as green composites, the present article reports on the incorporation of wood industry waste material, wood dust, as organic filler in film matrix based on Poly(Vinyl Alcohol) as continuous phase. In this study as filler, dust of Piyasal wood was used. In order to improve the compatibility between wood dust and plastic material, different amounts of cross-linking agents, such as glutaraldehyde, were used and the effect of these on water absorption and biodegradability was studied. The as-synthesized PVA-Wood dust composite materials are typically characterized by Fourier-Transformation Infrared (FTIR) spectroscopy and, wide-angle x-ray diffraction. The mechanical analysis of the composite material was studied by tensile test. The morphological image of as-synthesized materials was studied by optical microscope (OM).
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Mechanical properties and deformation mechanisms of polypropylene (PP)/wood fiber (WFb) composites modified with maleated polypropylene as compatibilizer and styrene-butadiene rubber (SBR) as impact modifier have been studied. The addition of maleated polypropylene to the unmodified polypropylene/wood fiber composite enhances the tensile modulus and yield stress as well as the Charpy impact strength. SBR does not cause a drop in the tensile modulus and yield strength because of the interplay between decreasing stiffness and strength by rubber modification and increasing stiffness and strength by good interfacial adhesion between the matrix and fibers. The addition of both maleated polypropylene and rubber to the polypropylene/wood fiber composite does not result in an improvement of effects based on maleated polypropylene and rubber, which includes possible synergism. The deformation mechanisms in unmodified polypropylene/wood fiber composite are matrix brittle fracture, fiber debonding and pullout. A polymeric layer around the fibers created from maleated polypropylene may undergo debonding, initiating local plasticity. Rubber particle cavitation, fiber pullout and debonding were the basic failure mechanisms of rubber-toughened polypropylene/wood fiber composite. When maleated polypropylene was added to this composite, fiber breakage and matrix plastic deformation took place. Polym. Compos. 25:521–526, 2004. © 2004 Society of Plastics Engineers.