Anionic copolymers of octanelactam with laurolactam (nylon-8/12)—IV. Dynamic thermomechanical and mechanical properties

The thermomechanical and the mechanical properties of a recent series of copolyamides of octanelactam (OL) and laurolactam (LL) (nylon-8/nylon-12) were studied. The glass transition temperature (T_g) and melting point (T_m) were determined with dynamic mechanical thermal analyser, and compared to those obtained with differential scanning calorimetry and the activation energy for glass transition was calculated. The copolyamides showed a minimum for tensile strength, yield stress, stress at 100% and modulus and a maximum for elongation at break at the composition 60/40 (OL/LL) which has the lowest crystallinity. Young's modulus against % elongation showed the classification of copolyamides in two groups (rich in OL or LL, respectively).