Premium
Correlation between nanohole volume and mechanical properties of amine‐cured epoxy resin blended with poly(ethylene oxide)
Author(s) -
Ramos J. A.,
Larrañaga M.,
Mondragon I.,
Salgueiro W.,
Somoza A.,
Goyanes S.,
Rubiolo G. H.
Publication year - 2009
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1242
Subject(s) - epoxy , materials science , composite material , ethylene oxide , flexural strength , positron annihilation , oxide , toughness , polymer , positron , copolymer , electron , metallurgy , physics , quantum mechanics
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.