Properties of carbon nanotube reinforced linear low density polyethylene nanocomposites fabricated by cryogenic ball-milling

A cryogenic ball-milling process to produce polymer/CNT nanocomposites was investigated. Linear low density polyethylene was used as the matrix material and 1 wt % of multiwalled carbon nanotubes (MWCNT) was used as reinforcement. The influence of the milling time and balls size was evaluated. The morphology of the nanocomposite and the degree of dispersion of the MWCNTs were studied using scanning electron microscopy (SEM), visual inspection, and light transmission microscopy; ropes as well as aggregates of MWCNTs were observed, and there was evidence of wetting of the nanotubes by the matrix polymer. An increase of up to 28% in the elastic modulus (determined by tensile testing) with respect to the matrix was obtained. Differential scanning calorimetry (DSC) analysis showed evidence of increase in the degree of crystallization, a result of the nucleating capability of the carbon nanotubes in the matrix. The degradation temperature of the nanocomposites does not show significant variations with respect to the unfilled polymer.