The effect of titanate nanotube/Y2W3O12 hybrid fillers on mechanical and thermal properties of HDPE-based composites

Hybrid fillers have triggered significant research in the field of polymer-based composites because they offer a range of properties that cannot be achieved by a single filler. Here a novel hybrid filler comprised of titanate nanotubes (TTNT) and Y2W3O12, a thermomiotic ceramic, was incorporated into a high density polyethylene matrix (HDPE) at an extremely low concentration (2 mass %). The influence of TTNT/Y2W3O12 mass ratio (1:1, 1:2 and 2:1), surface treatment of hybrid filler with cetyltrimethylammonium bromide (CTAB) and chemical modification of HDPE with polyethylene-grafted maleic anhydride (PE-g-MA), on the resulting mechanical and thermal properties of HDPE-based composites was investigated. The largest increase (25%) in Young's modulus and the greatest reduction (23%) in coefficient of thermal expansion (CTE) of HDPE was achieved for 2:1 TTNT/Y2W3O12 mass ratio, without significant alteration of thermal degradation beginning or thermal conductivity of HDPE. At this optimum TTNT/Y2W3O12 mass ratio, CTAB treatment of fillers was more efficient than PE-g-MA modification of matrix promoting a better dispersion of TTNT/Y2W3O12, leading to an increase of 34% in composite stiffness and a CTE reduction of 18%, although both treatments improved hybrid filler-matrix interfaces, as judged by a rise of 6% in yield strength