In Situ Copolymerization of Lactams for Melt Spinning

The copolymerization of lauryl lactam (LL) with ε‐caprolactam (ε‐CL) initiated by the latent, CO2‐protected N‐heterocyclic carbene‐based initiators 1,3‐dicyclohexyl‐3,4,5,6‐tetrahydropyrimidinium carboxylate (6‐Cy‐CO2), and 1,3‐dimethyl‐3,4,5,6‐tetrahydropyrimidinium carboxylate (6‐Me‐CO2) has been explored. The temperature‐dependent exchange of the protecting group in 6‐Cy‐CO2 and 6‐Me‐CO2 with 13C‐labeled CO2 is studied to gain knowledge about the onset of CO2 release from the carbene. Under exclusion of moisture, a storable batch containing 75 wt% ε‐CL, 25 wt% LL, and another 5 wt% 6‐Cy‐CO2 can be prepared. This batch is successfully used in the in situ melt spinning of poly(ε‐CL)‐co‐poly(LL)‐based single‐filament fibers. The copolymerization of lauryl lactam (LL) with ε‐caprolactam (ε‐CL) initiated by latent, CO2‐protected N‐heterocyclic carbene‐based initiators allows for the in situ melt spinning of poly(ε‐CL)‐co‐poly(LL)‐based single‐filament fibers.