Correlation between nanohole volume and mechanical properties of amine‐cured epoxy resin blended with poly(ethylene oxide) |
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| Authors: | J A Ramos M Larrañaga I Mondragon W Salgueiro A Somoza S Goyanes G H Rubiolo |
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| Institution: | 1. Materials and Technologies Group, Escuela Politécnica, Dpto. Ingeniería Química y M. Ambiente, Universidad País Vasco/Euskal Herriko Unibertsitatea, Donostia‐San Sebastián, Spain;2. Instituto de Física de Materiales Tandil (IFIMAT), Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399,B7000GHG Tandil, Argentina;3. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, Calle 526 e/10 y 11, 1900 La Plata, Argentina;4. Laboratorio de Polímeros y Materiales Compuestos, FCEyN, Universidad Nacional de Buenos Aires, Pabellón 1 Ciudad Universitaria,Buenos Aires (1424), Argentina;5. Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Argentina;6. Unidad de Actividad Materiales, Comisión Nacional de Energía Atómica (CNEA—CAC), Avda Gral Paz 1499, B1650KNA San Martín, Argentina |
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| Abstract: | A set of diglycidylether of bisphenol‐A (DGEBA)/4,4′‐diaminodiphenylmethane (DDM) epoxy matrix modified with poly(ethylene oxide) (PEO), pre‐cured at two different temperatures, was examined by positron annihilation lifetime spectroscopy (PALS). The aim was to investigate the correlation between local free volume and mechanical properties. A negative deviation from the linear additivity rule of the local free volume is observed at both cure schedules. Using together the local free volume and mechanical results allows to conclude that the cure temperature makes small contribution to the flexural strength and modulus of blends but is responsible for the composition‐dependent rise of the fracture toughness. It is proposed that this behavior is a consequence of the nearest‐neighbor intrachain contacts or self‐association of the epoxy‐OH groups during cure leading to a non‐uniform space distribution of the DGEBA–PEO contacts, which causes the deflection of the crack path. Copyright © 2008 John Wiley & Sons, Ltd. |
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| Keywords: | epoxy resins blends antiplasticization PALS toughness |
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