Thermally stable carbamates as novel photobase generator

Abstract

Six carbamates were prepared as novel photobase generators (PBGs), and their photo-reactivity and thermal stability were investigated. The introduction of an alkyl substituent into NH moiety in O-carbamoyloximes and/or the use of naphthalimide moieties instead of oxime moieties gave higher temperature of thermal decomposition (Td). These carbamates were photo-decomposed on irradiation at 254 nm, and the photolysis rates of oxime carbamates were higher than those of naphthalimide carbamates. The generation of amines from naphthalimide carbamates was confirmed by HPLC analysis of irradiated solutions. Although corresponding amines were not detected from oxime carbamates, the formation of 2-acetonaphthone was observed, suggesting the formation of the other type of basic compounds after photolysis. Films of poly(glycidyl methacrylate) containing oxime carbamates or naphthalimide carbamates became insoluble on irradiation followed by post-exposure bake. © 2005 TAPJ.