Fracture behaviour of PP based composites reinforced with micro and nano-sized fillers

CELINA BERNAL; EZEQUIEL PÉREZ; VERA ALVAREZ; LUCÍA FAMÁ; CLAUDIO JAVIER PÉREZ

Budapest

Congreso; 14th European Conference on Composite Materials; 2010

A widely-used practice in industry to obtain new materials with improved properties at relatively low cost is the incorporation of both micro- and nano-sized fillers into polymers. In the present work, polypropylene (PP) and 5 wt % of different nano and micro-sized fillers (organo-modified clay, SiO2 nanoparticles, Al2O3 nanoparticles or CaCO3 particles) were mixed in an intensive mixer. Composites with different CaCO3 content were also prepared and the effect of the incorporation of MAPP in the composites formulation was also analysed. Fracture tests on double-edge-notched tensile specimens (DENT) were carried out for the PP matrix, the blend of PP and MAPP and the different composites with and without MAPP. All materials exhibited non-linear fracture behaviour until maximum load and unstable crack growth at a certain point in the load-displacement curve. Therefore, the J-Integral parameter at instability (Jc) was adopted to characterise the materials fracture behaviour. A decreasing trend of fracture toughness with CaCO3 content was observed. Furthermore, the addition of MAPP as coupling agent led to more brittle composites for most of the fillers probably as a result of a higher interfacial adhesion which hindered the toughening mechanism of particle debonding and subsequent matrix ductile tearing.