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The effect of steric hindrance on physical properties in an amine‐cured epoxy
Author(s) -
Duffy James V.,
Lee Gilbert F.
Publication year - 1988
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.1988.070350521
Subject(s) - steric effects , amine gas treating , epoxy , glass transition , polymer chemistry , materials science , chemistry , organic chemistry , polymer
A pair of aliphatic amines were synthesized in order to study the effect steric hindrance has on the physical properties of an amine‐cured epoxy resin. The hindered amine (TMSiDA) has NH 2 groups that are obstructed by the presence of adjacent methyl groups while the unhindered amine (SiDA) does not contain any NH 2 steric hindrance. DGEBA cured with TMSiDA is less dense, absorbs less moisture, and has a higher T g than does SiDA/DGEBA. Torsional pendulum results show that TMSiDA/DGEBA has a slightly higher rubbery modulus and a secondary transition at a lower temperature than DGEBA cured with SiDA. Activation energies for the secondary transition were determined for TMSiDA/DGEBA and SiDA/DGEBA and are 19 and 14 kcal/mol, respectively.