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Viscoelastic properties of epoxy resin. I. Effect of prepolymer structure on viscoelastic properties
Author(s) -
Hata Naoaki,
Kumanotani Ju
Publication year - 1971
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.1971.070151005
Subject(s) - diglycidyl ether , epoxy , materials science , viscoelasticity , glass transition , prepolymer , polymer chemistry , reactivity (psychology) , dynamic mechanical analysis , composite material , dynamic modulus , polymer , bisphenol a , polyurethane , medicine , alternative medicine , pathology
The intermolecular cyclization reaction is investigated in highly crosslinked epoxy systems, where diepoxides with different mobilities between terminal epoxy groups were crosslinked with ethylene diamine. Based on the measured values of the Clash‐Berg 10‐sec modulus in the rubbery region, the correlation between the mobility and the cyclization reactivity of the diepoxides is discussed. The epoxide with higher mobility is found to have a higher rubbery modulus than that with lower mobility, as was expected. This is tentatively explained by the difference in the reactivity of the formation of the 11‐membered ring. Dynamic mechanical measurements were also run on a forced vibration apparatus. The higher β‐transition peak of the polymer of bisphenol‐A diglycidyl ether was interpreted in terms of its higher free volume as well as lower density and lower glassy modulus. The higher modulus in the glassy region of ethylene glycol diglycidyl ether–ethylenediamine was explained on the basis of hydrogen bonding.