Experimental and theoretical analyses of mechanical properties of PP/PLA/clay nanocomposites

Compatibilized and non-compatibilized blends of polypropylene (PP) and poly(lactic acid) (PLA) with various compositions containing nanoclay particles were prepared by one step melt compounding in a twin screw extruder. Two nanocomposite systems with different matrices i.e. PP-rich (75/25 composition) containing Cloisite 15A and PLA-rich (25/75 composition) containing Cloisite 30B were selected for investigation of effect of nanoclays and n-butyl acrylate glycidyl methacrylate ethylene terpolymers (PTW) as compatibilizer on mechanical properties of PP/PLA/clay nanocomposites. Tensile and impact properties of the nanocomposite systems were investigated and correlated with their microstructures. Tensile modulus and strength of the blends were increased while elongation at break decreased by increasing PLA content. There was an irregular relationship between impact strength of the blends and PLA content. Several proposed models for blends and nanocomposites were used for prediction of tensile modulus of the samples. Most of the proposed models for blends could predict the tensile modulus of the blends successfully at low content of PLA. Another notable point was that most of the micromechanical models for nanocomposites fitted well to experimental values at low content of the clays and showed deviations at high clay loadings.