Polymerization of 2-azabicyclo[2,2,1]hephan-3-one and its copolymerization with 2-pyrrolidone

Abstract

The anionic ring opening polymerization of a bridged bicyclic lactam monomer, 2-azabicyclo[2.2.1]heptan-3-one (abbreviated as ABHO), was carried out in both bulk and solution under various reaction conditions. In general, the bulk polymerization of ABHO found to be superior over the solution polymerization in terms of their conversion efficiency and viscosity. In the bulk polymerization of ABHO, the maximum conversion of 70% and viscosity of 0.45 dl/g were observed. The resulting polymer exhibited excellent thermal stability up to 300℃. Melting point and decomposition temperature of this polyamide, poly(cyclopentane-1,3-diyliminocarbonyl), were about 307℃ and 335℃, respectively. This high thermal stability may be due to the presence of stable cyclopentane ring structure in the polymer backbone which causes high stiffness of the polymer chain. Copolymerization of ABHO with 2-pyrrolidone was also studied with varying weight percentage of ABHO using KOH as a catalyst and $CS_2$ as an initiator at 30℃. Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) measurements showed that thermal stability of these copolymers were highly improved. For instance, decomposition temperature of the copolymer containing 15 weight percent of ABHO was stabilized at about 30℃. Thermal stability of copolymer was greatly improved as the weight percentage of ABHO is increased.