Maleated high density polyethylene (mPE) loaded with 2, 4, 6 and 8 wt% SiC nanoparticles (SiCnp) were prepared by injection molding. The effect of SiCnp additions on the microstructure and mechanical properties of mPE were studied using X-ray diffraction (XRD), polarizing optical microscopy (POM), heat deflection temperature (HDT), tensile and Izod impact measurements. XRD and POM results showed that the SiCnp additions reduce the crystallite thickness and spherulite size of mPE. HDT measurements revealed that SiCnp additions enhance the thermal stability of mPE considerably. Tensile test showed that the addition of 2 wt% SiCnp improves the Young's modulus and yield strength of mPE at the expenses of elongation at break and impact strength. SEM fractography was used to reveal the failure deformation of nanocomposites after impact test. The low impact strength of mPE/SiCnp nanocomposites was related to the absence of particle cavitation and matrix fibrillation. The impact fracture deformation of such nanocomposites is discussed. (C) Koninklijke Brill NV, Leiden, 2011