Thermoplastic polyurethane (TPU) matrix was reinforced with polyhedral oligomeric silsesquioxane (POSS) and halloysite nanotubes (HNT), both separately and combined. Composite samples were fabricated using a melt-compounding method. Characterization of the composites obtained was performed via tensile and hardness tests, melt-flow index measurements (MFI), abrasion tests, dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM) to investigate the mechanical performance, flow behaviour, tribological characteristics, thermo-mechanical response and morphological properties. The greatest tensile strength value was obtained for the smallest HNT content. Further addition of HNT resulted in agglomerations for both POSS and HNT particles. The shore hardness of TPU was enhanced by filler inclusions. The TPU/POSS composites displayed significant improvement in terms of abrasion resistance compared to TPU at lower loading levels. The DMA study showed that composites containing 0.5% POSS and 1.0% HNT displayed the greatest storage modulus. The glass-transition temperature of TPU shifted to smaller values with the addition of both nanoparticles. The HNT inclusions increased the MFI value of TPU because of their large aspect ratio. Homogeneous mixing of nanoparticles in the TPU matrix was confirmed by a SEM study of the composites. Their dispersion decreased as the concentrations of POSS and HNT increased. An adjuvant effect of POSS with HNT was achieved in their hybrid composites.

Carbon nanotubes (CNTs) and silicon carbide nanoparticle (nano-SiCp)-reinforced magnesium (Mg) matrix hybrid composites were prepared through a three-step melt spinning process (ball milling, mechanical stirring, and ultrasonic vibration processing). The hybrid nanoreinforcements showed high strengthening efficiency by which the yield and tensile strength of the hybrid composites experienced 46.7 and 15.2% increment, respectively, compared with the matrix alloy. Obviously, the mixed ball-milling process of SiC nanoparticles and CNTs promoted the dispersion of each other, and both the uniformly distributed SiC nanoparticles and CNTs contributed to the enhanced mechanical performance of the hybrid composites. Besides, the addition of the hybrid nanoreinforcements induced the precipitation of nanosized rod-like MgZn2 phases in the as-extruded composites which also made a contribution to the enhanced performance of the composites. Investigations on the strengthening mechanisms of the hybrid composites show that it originates from grain refinement, load transfer, precipitation enhancement, and Orowan reinforcing. More importantly, the contribution made by each part was analyzed in detail.