Polyethylene grafted silica nanoparticles via surface-initiated polyhomologation: A novel filler for polyolefin nanocomposite

Abstract

Silica nanoparticles (SiO 2 NPs) were prepared and functionalized with polyethylene (PE@SiO 2 NPs) using the surface-initiated polyhomologation (SI-polyhomologation) technique. Polyolefin nanocomposites were fabricated later by melt mixing of different ratios of the as-prepared SiO 2 NPs and PE@SiO 2 NPs with linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) matrices. Firstly, SiO 2 NPs were modified with different alkoxysilane ligands, dichloro(divinyl)silane (DCDVS), allyl trimethoxysilane (ATMS), and vinyl triethoxylsilane (VTES). Subsequently, thexylborane, an initiator for SI-polyhomologation, was immobilized to the modified surface of SiO 2 NPs through hydroboration reactions. Polyhomologation was then allowed to proceed by adding monomer solution to form polyethylene brushes covalently bonded to the surface of the NPs. Physiochemical characterizations had confirmed the morphology, chemical structure, and thermal stability for each step of modification reactions. LLDPE and LDPE nanocomposites were prepared by extrusion with SiO 2 NPs and PE@SiO 2 NPs as nanofillers. Finally, tensile tests and morphological SEM-based analyses are presented to discuss the influence of the grafted PE on both the dispersion of the fillers and the mechanical properties of the filler/matrix interphase. • Polyethylene grafted nanosilica. • SI-Polyhomologation. • Polyolefin/silica nanocomposites.