• anionic polymerization;
  • polylactams;
  • reactive extrusion;
  • reactive processing;
  • thermogravimetric analysis


Anionic ring-opening polymerization of lactams leads to the formation of poly(lactams) or polyamides. This work aimed at comparing the performance of four methods for measuring the conversion of ε-caprolactam (CL) to polyamide 6. The latter was either a homopolymer (PA6) or grafts onto polystyrene (PS-g-PA6 graft copolymer). Those four methods were mass balance based on solvent extraction (methanol, water, THF, or acetone), mass balance based on vacuum drying at 140°C, thermogravimetric analysis (TGA), and elemental analysis based on nitrogen. The mass balances based on methanol extraction and vacuum drying at 140°C and TGA were all suitable for measuring the conversion of CL, whether the resulting polymer was the PA6 or PS-g-PA6. The mass balance based on water extraction was good for the PA6 and not good for the PS-g-PA6. The elemental analysis based on nitrogen was not suitable for the PA6 nor for the PS-g-PA6. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1972–1981, 2006