Nonlinear organic reaction of 9-fluorenylmethyl carbamates as base amplifiers to proliferate aliphatic amines and their application to a novel photopolymer system

Abstract

A novel concept of base proliferation for improving the photosensitivity of base-sensitive materials is described by presenting the autocatalytic transformation of 9-fluorenylmethyl carbamates to aliphatic amines. A 9-fluorenylmethyl carbamate, as a base amplifier, was subjected to a base-catalysed fragmentation reaction to liberate the corresponding amine, which can then act as a catalyst for decomposing parent molecules, leading to autocatalytic decomposition. Consequently, the amine is generated from an equimolar amount of the carbamate using a catalytic amount of the same amine. 1-(9-Fluorenylmethoxycarbonyl)piperidine and 1-(9-fluorenylmethoxycarbonyl)cyclohexylamine were suitable as base amplifiers because of their thermal stability under neutral conditions and high base-catalytic reactivity. On the basis of the results, 1,3-bis[1-(9-fluorenylmethoxycarbonyl)-4-piperidyl]propane and 1,6-bis[(9-fluorenylmethoxy)carbonylamino]hexane were designed as base amplifiers which liberate aliphatic diamines to crosslink poly(glycidyl methacrylate) photochemically in the presence of a photobase generator. Addition of the base amplifiers resulted in a marked improvement of the photosensitivity characteristics of the polymer by a factor of 16 and 50, respectively.