The (Co)Polymerization of the Cyclic Diamide 1,6-Diazacyclododecane-7,12-Dione

Abstract

Abstract It is demonstrated for the first time that the cyclic diamide 1,6- diazacyclododecane-7,12-dione (c-4) can be polymerized. Polyamide 46 was prepared by thermal or hydrolytic ring-opening polymerization of c-4. c-4 polymerized in the melt to form polyamide 46, containing approximately one-third of the original c-4. Due to possible degradation of c-4 near its melting point, the polyamide 46 formed possibly contained a crosslinked fraction which was insoluble. Therefore, the thermal behavior deviated from that of Stanyl (a commercial polyamide 46 from DSM, The Netherlands). Furthermore, polyamide 46 was prepared by anionic polymerization of c-4 in N-methyl-2-pyrrolidone solution at 202°C. c-4 polymerized with NaH and 1,6-hexamethylene diisocyanate as catalysts. Almost all c-4 was converted to polyamide 46. Due to possible crosslinking, the polyamides had difficulties in dissolving. Furthermore, the thermal behavior of this low molecular-weight polyamide 46 deviated from that of Stanyl, but solid-state postcondensation had a positive effect on the melting point. Then copolyamides of e-caprolactam (CL) and c-4 were prepared by anionic ring-opening copolymerizations. The cyclic monomers polymerized in the melt with lactam magnesium bromide and isophthaloyl-bis-caprolactam as catalysts. It was demonstrated that approximately all c-4 was copolymerized with CL at 180°C. At 200°C only ∼ 30% was incorporated. The copolymerization of a maximum of 8.5 mol% c-4 in polyamide 6 showed no effect on the thermal behavior and crystallinity as compared to polyamide 6.