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The mechanical characteristics of flax fibers were optimized by using the NaOH treatment process to improve the properties of composite materials. Shrinkage of the fibers during this treatment had a significant effect on the structure and, as a result, on the mechanical properties of the fibers and the composites based on them. Due to the higher mechanical strength and stiffness of flax fibers after NaOH treatment under isometric conditions, the strength and stiffness of composites in general increase. Further, NaOH treatment leads to a rougher surface morphology, as shown, e.g., for jute fibers, compared with the surface of untreated fibers without improved fiber/matrix adhesion. 相似文献
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The influence of mixing process (in a two-roll mill, high-speed mixer, or twin-screw extruder) on the strength properties
of polypropylene/wood fiber composites was studied. The best results were obtained for composites compounded in a twin-screw
extruder. The water uptake and the influence of moisture on the flexural strength (σfl) and modulus (Efl) were studied by immersion of the composites in water at 20, 50, and 90°C. Most strongly the moisture affected the value
of Efl, but the degree of water uptake and the change in σfl and Efl also depended on temperature and the presence of a modificator—maleated polypropylene (MAH). MAH improved the strength properties
of the composites both in dry and wet states and also decreased the extent of water uptake and swelling in cyclic (soaking/drying)
tests.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 42, No. 1, pp. 101–114, January–February, 2006. 相似文献
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R. Merijs Meri T. Bocoka J. Zicans M. Kalnins V. Kalkis A. K. Bledzki 《Mechanics of Composite Materials》2008,44(4):361-370
Changes in the toughness of crystalline poly(ethylene terephtalate) upon addition of two elastomers — ethylene-propylene-diene
terpolymer and ethylene-α-octene copolymer — are investigated. Blends with increasing elastomer content (up to 30 wt.%) were obtained and modified
by γ-radiation up to a 300-kGy absorbed dose. The interrelation between the toughness and certain tensile characteristics (elastic
modulus, yield stress, ultimate stress, elongation at break, and specific fracture energy) of the blends, with various structural
features of components (crystallinity and the degree of cross-linking) and morphology of the blends, is discussed.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 4, pp. 521–534, July–August, 2008. 相似文献
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Wood-filled thermoplastic composites 总被引:1,自引:0,他引:1
Different physical properties of wood-filled thermoplastic materials produced by a special mixing and extrusion process are examined. The results show that the wood content and the kind of plastics are the main parameters that control the physical properties of composites. In general, wood-filled thermoplastic materials exhibit mechanical properties comparable to those of customary wood fiber products, i.e., medium density fiberboard (MDF); however, they show distinctly better behavior than the MDF and natural wood after exposure to moisture.Presented at the 10th International Conference on the Mechanics of Composite Materials (Riga, April 20–23, 1998).Universität Kassel, Institut für Werkstofftechnik, Kunstoff-und Recyclingtechnik, Mönchebergstraße 3, 34109 Kassel, Germany. Published in Mekhanika Kompozitnykh Materialov, Vol. 34, No. 6, pp. 795–802, November–December, 1998. 相似文献
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In real composite materials an additional phase may exist between the fiber and the matrix. This phase, commonly known as the interphase, is a local region that results from the matrix bonds with the fiber surface or the fiber sizing. The differing thermal expansions or contractions of the fiber and matrix cause thermally induced stresses in composite materials. In the present study, a four-cylinder model is proposed for the determination of residual thermal stresses in unidirectional composite materials. The elastic modulus of the interphase is a function of the interphase radius and thickness. The governing equations in terms of displacements are solved in the form of expansion into a series [1]. The effective elastic characteristics are obtained using the finite element approach. The effect of the interphase thickness and different distributions of the interphase Young's modulus on the thermal residual stress field in unidirectional composite materials is investigated.For Pt. 1, see [1].Published in Mekhanika Kompozitnykh Materialov, Vol. 33, No. 2, pp. 200–214, March–April, 1997. 相似文献