Synthesis of Polyamide 6 by Anionic Polymerization of ε-Caprolactam in an Internal Mixer: Effect of Polymerization Reaction Time

The main objective of the present work was to synthesis polyamide 6 through anionic polymerization of ε-caprolactam in an internal mixer. The reaction time and the rheological properties of samples during the polymerization were studied. The samples were characterized by Thermo Gravimetry Analysis (TGA), Differential Scanning Calorimeter (DSC) and FT-IR spectrometer. The melt flow behavior and viscoelastic properties of the samples were studied by using a Rheometric Mechanical Spectrometer (RMS). The polymerization reaction was found to be very fast such that it completed within 6 minutes as could be detected by following the mixing torque which reached to a steady state after passing a maximum. These results suggest that there is a reaction time above which the viscoelastic behavior of the samples almost remained unchanged, while the viscosity and elasticity of the samples continue to decrease with polymerization reaction time as a result of thermochemical degradation.