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New polythiourethane hardeners for epoxy resins
Author(s) -
Strzelec Krzysztof,
Leśniak Elżbieta,
Janowska Grażyna
Publication year - 2005
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.1861
Subject(s) - epoxy , curing (chemistry) , materials science , toughness , ultimate tensile strength , thermal stability , composite material , polymer , swelling , polymer chemistry , chemical engineering , engineering
New mercaptan‐terminated polythiourethanes were synthesized from low‐molecular‐weight dimercaptan oligomers and diisocyanates. The characteristic bands in the FT‐IR spectra, and the specific peaks in the 1 H‐NMR spectra correlate rather well with the proposed structures of these polymers. Chemical analysis of the epoxy group conversion and swelling measurements were conducted in order to determine the crosslink densities of the cured epoxy resins. The curing characteristics and thermal behaviour of the formulated curing mixtures indicate that the epoxy/polythiourethane stoichiometry and thermal history during cure may greatly affect the curing mechanism and final properties of the epoxy networks. Mechanical studies indicated that the application of polythiourethane hardeners improves the flexibility with increasing tensile strength and impact toughness. The prepared polythiourethane hardeners have an acceptable odour and give a perfectly homogeneous system with the epoxy resins and have good storage stability with other coreactants such as diamines. Copyright © 2005 Society of Chemical Industry