Analyses of the effect of carbon nanotube on the mechanical, tribological and thermal behaviour properties of high-impact polystyrene nanocomposites

This study evaluated the incorporation of multi-walled carbon nanotubes (CNTs) into high-impact polystyrene (HIPS) matrices. Nanocomposites containing 0.3% and 0.5% by weight of CNTs were prepared and processed by injection moulding. Characterization involved structural analysis, mechanical, tribological, morphological, and thermal tests. The results indicated that the addition of NTCs increased the modulus of elasticity and impact resistance of HIPS, restricting the mobility of matrix molecules. In wear tests, the nanocomposites showed a significant reduction in the coefficient of friction (from 0.98 in the pure polymer to up to 0.55) and in mass loss, marking the transition from severe adhesive wear to mild and controlled wear. However, the sample with 0.5% CNT exhibited a higher specific wear rate and cavity volume than the 0.3% sample, due to greater transfer of CNTs to the metallic counterface. Thermally, CNTs delayed degradation and acted as a protective barrier during the degradation process, reducing the flame propagation rate by up to 17.1%. It is concluded that the addition of low fractions of CNTs to HIPS simultaneously optimises its mechanical, thermal, and tribological performance.