PEREZ Claudio javier
congresos y reuniones científicas
Effect of water absorption on the dynamic-mechanical properties of polyester based composites
E. FAGUAGA; C. J. PÉREZ; V. ALVAREZ; E. RODRIGUEZ
Simposio; IX Simposio Argentino de Polímeros; 2011
During the last decades, fiber-reinforced plastics have been an alternative to other materials such as metal and steel, in several applications because this kind of materials exhibits high specific tensile and compressive strength, good fatigue and corrosion resistance being appropriateness for the manufacture of complex-shape components in shorter times. Wind energy is one of the fields in which long-term durability is required and exposure to aggressive environments is common. Offshore mills are exposed to high humidity that could affect the integrity of the composites blades, reducing the lifetime of the components. Moreover, the inspection and reparation operations are more difficult in those conditions, which impose the need of using materials that could withstand the hygrothermal degradation. It has been reported that water absorption can affect the mechanical performance of turbine blades, especially fatigue, which is the most common failure mode in these components (Lee et al 1992, Gellert et al 1999). In this work, glass fiber/unsaturated polyester composites (with and without bentonite) were produced by using the VARI (vacuum assisted resin infusion) technique. The fabricated specimens were immersed in water at 80ºC for different periods of time. DMA (dynamic mechanical analysis) technique was employed to investigate the matrix degradation and interfacial debonding of the aged specimens. The gradually decreased Tg (glass transition temperature), E (storage modulus), and the increased tan δ (energy dissipation) with extended exposure time were used to measure this effect. Mathematic models were used to predict the dynamical-mechanical behavior of studied materials and to predict the evolution of modulus as a function of temperature but also to analyze the effect of water on the mechanical properties.