Thermal stability of some naphthalene- and phenyl-based epoxy resins

Abstract

Six epoxy monomers were synthesized and cured using 4,4'-methylenedianiline (DDM). The glass transition temperatures (Tg) of naphthalene- and phenyl-based epoxy resins were in the ranges 175-213℃ and 128e200℃, respectively. Naphthalene-based epoxy resins 1,5-bis(2,3-epoxypropoxy)naphthalene (A) and 2,7-bis(2,3-epoxypropoxy)naphthalene (B) have almost equal LOIs, implying that the effects of the position of the substituent on LOI was very weak. 4,4'-Bis(2,3-epoxypropoxy)benzylideneaniline (D) has the lowest LOI. The same trend was exhibited when some of the epoxy monomers were cured using the curing agent, sulfanilamide (SAA). The order of the LOIs of the epoxy resins was (B) = (F) > (A) > (E) > (C) > (D), when cured using 4,4'-methylenedianiline (DDM). Degradation proceeds in a single stage in an atmosphere of nitrogen and in two stages in air. At 800℃, the epoxy polymer (D) has the highest char yield of all the epoxy resins.