Glycolysis of epoxide-amine hardened networks. I. Diglycidylether/aliphatic amines model networks
Résumé
Epoxide-amine hardened networks are high performance materials in composites, coatings and adhesives area. Solvolysis is an efficient method of polymer waste valorisation, particularly for fibre-reinforced composites, allowing recovery of inorganic parts (fibres, charges, metals), whereas the matrix yields depolymerization products which may be recycled in useful raw materials for the chemical industry.
However, the curing of epoxides with amines results from non-reversible condensation reactions, and then, the controlled depolymerization by chemical reactives seems to be impossible.
We have found that the networks from diglycidylether of bisphenol-A (DGEBA) cured with polyamine may be decomposed by glycols, in relatively mild conditions, leading to 'liquefaction' of the matrix. A solvolytic cleavage of ether linkages, originally present in the DGEBA molecular structure, has been identified. Apparently, the reaction is a transetherification one. Depolymerization products are, for a part, aromatic hydroxyl terminated low molecular weight compounds.