Determination of oligomer 340 and polyamines in cured epoxy resins by extraction and high-performance liquid chromatography

Abstract

The efficiency of acetone in extracting unreacted oligomer 340 and aliphatic polyamine hardeners (diethylenetriamine and triethylenetetramine) from cold-cured epoxy resins was studied. Finely scratched slices of cured resin were extracted ultrasonically with acetone. The extracted oligomer 340 and polyamines were determined by high-performance liquid chromatography. The extraction efficiency of acetone for unreacted oligomer 340 was over 90% and that for the polyamines varied from 76 to 97%. The procedure was applied to study the curing rate of five commercial epoxy resins. The unreacted amounts of both oligomer 340 and polyamine decreased rapidly within 1–2 d in all the products studied. After curing for 2–3 d the unreacted amounts decreased only slowly. The proposed method can be used to evaluate health risks of cured epoxy products and to obtain information about curing kinetics.