Synthesis of aliphatic polyamide bearing fluorinated groups from e-caprolactam and modified cyclic lysine
Résumé
Aliphatic polyamide (PA) bearing fluorinated groups was synthesized in bulk with
perfluorobutyryl-substituted a-amino-e-caprolactam and e-caprolactam by anionic ringopening
polymerization (AROP). The fluorinated monomer was obtained by condensation
between cyclic lysine (i.e. a-amino-e-caprolactam) and perfluorobutyryl chloride. The
effect of the fluorinated monomer fraction onto the AROP of e-caprolactam was monitored
by the exothermicity of this polymerization versus time. The properties and characteristics
of the resulting polymers were studied by with differential scanning calorimetry,
thermogravimetry, magic angle spinning NMR, FT-IR, and contact angle measurements.
Polyamides bearing fluorinated groups exhibited better thermal stability than polyamide
6 (PA6) as well as a higher hydrophobic surface character as evidenced by surface tension
measurements. The glass transition temperature of polyamide 6 was 53 C and rose to
58 C for a PA bearing fluorinated moieties, while fluorinated monomer insertion induced
a decrease of the melting points from 216 to 198 C. These copolymers displayed a
maximum degradation temperature of 390 C as compared to the 310 C for PA6, and their
surface energies decreased from 49.4 mN cm1 (PA6 value) to 44.1 mN cm1