Polyamide 12/fullerene C60 composites: investigation on their mechanical and dielectric properties

The effect of fullerene C-60 on mechanical properties of polymer nanocomposites based on PA12 was investigated. The nanocomposites were prepared by in situ polymerization. The Young's modulus and tensile strength of the polymer nanocomposites are improved by about 20 % with loading of 0.02-0.08 wt.% the fullerene C-60. Dielectric spectroscopy was used to investigate the influence of nanoparticles on the relaxation processes in polymer matrix. The segmental relaxation processes become faster with the fullerene C-60 addition, an effect associated with a decrease of the glass transition temperature. In contrast, the secondary or gamma relaxation process of PA12/ fullerene C-60 nanocomposites was observed to slow down with addition of fullerene C-60. These observations indicate that fullerene C-60 as filler has an effect opposite to antiplasticizing that slow down the secondary relaxation (stiffening the material) in the glass state, while at the same time reducing the alpha relaxation time associated with cooperative segmental motions. It behaviour can be connected with inclusion complex formation between PA12 and fullerene C-60.