Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group.T hermosetting epoxy and polyurethane polymer systems are widely used in many applications, including protective coatings, composite materials, and adhesives. These systems involve the reaction of functional polymers or oligomers with other materials containing mutually reactive groups. The composition of the reactants used determines the final properties of the thermoset coatings. Epoxy coatings generally exhibit good corrosion performance while polyurethane systems result in coatings having good toughness, abrasion resistance, and durability. Glycidyl carbamate chemistry has the potential of combining epoxy and polyurethane technology into a single system and has been shown to improve toughness in epoxy-amine systems. 1Reactions of amine with oxirane will occur at different rates depending on reactivity of the active amine hydrogen 2 and stoichiometric concentration of the amine relative to oxirane. 3,4 Amines used with epoxy resins are primary, secondary, or tertiary amines. Tertiary amines can, in turn, catalyze epoxide homopolymerization 5 (etherification). Amine structure also plays a factor in the overall reactivity of the primary and secondary amines. Reactivity is a function of steric factors 6,7 and amine basicity. 7-13 Amine reaction mechanisms using tetraglycidyl-4,4'-diaminodiphenylmethane (TGDDM) are also established in literature. 6,14-16 TGDDM reactions demonstrate that epoxide type also influences kinetics and deviates from diglycidyl ether bisphenol A (DGEBA) resins. 4,6 In this study, we will examine the crosslinking of trifunctional glycidyl carbamate resins with several amines.The glycidyl carbamate (GC) group is readily synthesized from the reaction of an isocyanate with glycidol 17 ( Figure 1). Two types of intermolecular reactions are possible with the glycidyl carbamate group. The first is the reaction of the oxirane with the amine and the second is the selfcrosslinking reaction. We have seen from earlier work that the self-crosslinking reaction in the absence of amine forms a thermoset coating with an excellent combination of properties. 18 In the presence of amine ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.