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Polyester containing isocyanate groups—Modified epoxy resin: Rheological, dynamic‐mechanical, and impact properties
Author(s) -
Soares Bluma G.,
Gonçalez Viviane,
Galimberti Rurik,
Barcia Fabio L.,
Sirqueira Alex S.
Publication year - 2008
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21035
Subject(s) - epoxy , materials science , isocyanate , curing (chemistry) , glass transition , rheology , dynamic mechanical analysis , composite material , polyester , molar mass , impact resistance , scanning electron microscope , polyurethane , polymer
Low molar mass hydroxyl‐terminated polyester was functionalized with isocyanate groups (NCO) and used to improve the impact resistance of epoxy resin (ER) cured with triethylene tetramine (TETA). The effect of polyester‐based modifiers (with or without NCO groups) on the curing rate of epoxy/TETA system was investigated by rheological techniques. It was found that the functionalized polyester decreased the gel time, indicating an accelerating effect of the curing process. In addition, significant improvement in impact resistance of the epoxy network was achieved, with low detrimental effect on the glass transition temperature and stiffness. The modified epoxy systems did not present phase‐separated morphology discernible by scanning electron microscopy, even after the curing process. The glass transition temperature of the epoxy networks was also investigated by dynamic‐mechanical analysis. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers