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Characterization of epoxies cured with bimodal blends of polyetheramines
Author(s) -
McAninch Ian M.,
Palmese Giuseppe R.,
Lenhart Joseph L.,
La Scala John J.
Publication year - 2013
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.39322
Subject(s) - materials science , composite material , glass transition , fracture toughness , volume fraction , toughness , brittleness , epoxy , dynamic mechanical analysis , stoichiometry , polymer , chemistry
DGEBA was cured with bimodal blends of polyetheramines as well as with single molecular weight amines while maintaining stoichiometry. Glass transition temperatures ( T g s) and moduli were measured using dynamic mechanical analysis (DMA). Fracture properties were measured using the compact tension geometry and testing was performed at both ambient and non‐ambient temperatures, investigating toughness changes as a function of temperature. For constant amine average molecular weights, the addition of high molecular weight amines caused increased glassy moduli at a constant T − T g and decreased densities while broadening the glass transition without changing the fracture toughness. The fracture behavior, specifically the slip‐stick to brittle transition, was affected by the broadened transitions. T g , breadth of T g , and total damping were found to be proportional to the volume fraction of amine in the system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1621–1631, 2013