Mechanical properties and fracture behavior of poly(vinylidene fluoride)-polyhedral oligomeric silsesquioxane nanocomposites by nanotensile testing

The key static and dynamic mechanical properties and fracture behavior of nanocomposite films composed of a poly(vinylidene fluoride) (PVDF) matrix and different contents of polyhedral oligomeric silsesquioxane (FP-POSS) were researched by nano-tensile testing. The Young's modulus, storage modulus, loss modulus, loss tangent, yield strain, yield strength, tensile strength, fracture strength, fracture strain, fracture toughness and fracture deformations of all different nanocomposite systems were obtained. The influence of FP-POSS and its contents on the mechanical properties of PVDF was analyzed. Results showed that both the stiffness and toughness of PVDF were enhanced at some specific FP-POSS content and further additions of FP-POSS brought dramatic enhancements in toughness while associated with a decline in stiffness. Dynamical mechanical properties showed that FP-POSS increased the viscosity of PVDF. The mechanism of the effects of FP-POSS on PVDF was analyzed from the unique nano scale organic-inorganic molecular structure of FP-POSS and the micro structures of the nanocomposite films.