Chemical degradation of TGDDM/DDS epoxy resin in supercritical 1-propanol: Promotion effect of hydrogenation on thermolysis

Chemical decomposition of an epoxy system made of tetraglycidyl 4,4′-diaminodiphenylmethane (TGDDM) and 4,4′-diaminodiphenylsulfone (DDS) in supercritical 1-propanol was investigated under different reaction temperature and time. The GC-MS results suggested that the epoxy system was decomposed to the products including aniline, N-propylbenzenamine, and 4,4′-diaminodiphenylsulfone. The change of the products' yield with time was measured by GC. In addition, the formed chars were characterized by SEM, elemental analysis, Raman and XRD. The results implied the presence of some graphite microcrystals and disordered structure in the solid residue. Upon the addition of KOH, the Guerbet reaction of 1-propanol was promoted to generate more hydrogen. A possible free-radical reaction mechanism was proposed for the depolymerization of TGDDM/DDS epoxy resin. Hydrogenation of radicals had a promotion effect on thermolysis of TGDDM/DDS epoxy resin.