Propylene‐ethylene copolymer nanocomposites: Epoxy resin grafted nanosilica as a reinforcing filler

Abstract In the present work it is shown that low nanoparticle‐loaded polymer composites with improved mechanical performance can be prepared by a conventional melt blending technique in which the nanoparticles are chemically pregrafted by diglycidyl ether of bisphenol‐A (DGEBA). Two composites, each with 2.5 wt% filler, were developed. The first one was obtained by melt blending propylene‐ethylene copolymer (EP) with nanosilica in a co‐rotating sigma internal mixer. The second one was obtained by melt blending the same EP, but with DGEBA grafted nanosilica. The addition of epoxy resin grafted nanosilica to the polymer matrix produced a homogeneous dispersion of particles in the form of micro domains. The results of tensile tests indicate that epoxy resin grafted nanosilica particles (SiO₂‐g‐DGEBA) provide EP with stiffening, strengthening, and toughening effects at a 2.5 wt% loading level. This is a much lower level compared to most particulate fillers used for composites. There was no noticeable improvement in the mechanical properties when nanosilica was added to the neat polymer. However, the addition of SiO₂‐g‐DGEBA particles to the polymer matrix led to an increase of both elastic modulus and toughness (from 0.36 to 0.54 GPa, and 19.06 to 21.05 MJ/m³, respectively). POLYM. ENG. SCI., 26:806–812, 2005. © 2005 Society of Plastics Engineers