The influence of formulation and processing parameters on the thermal properties of a chitosan–epoxy prepolymer system

Abstract

Abstract Waterborne epoxy dispersions have been employed effectively for many years in response to environmental regulations aimed at reducing solvent levels in coatings. Very few non‐toxic bio‐based polyamines have been reported in the literature as curing agents for epoxy‐functional waterborne dispersions. Currently to our knowledge the only bio‐based amino hardener used to cure a waterborne epoxy prepolymer is ϵ ‐polylysine. Being one of the rare primary amine‐containing polymers of natural origin, chitosan is produced commercially by the deacetylation of chitin. In the work reported here, chitosan and oligochitosan were evaluated as curing agents for diepoxy prepolymers. A solvent‐free prepolymer (Epotec) and a waterborne prepolymer dispersion (Epirez) were both used. A crosslinked network was obtained when the reaction was performed with the waterborne epoxy dispersion. The influence of the hardener‐to‐epoxy prepolymer ratio on the crosslinking density was investigated. The thermal properties of networks were measured using differential scanning calorimetry and thermogravimetric analysis. © 2013 Society of Chemical Industry