Polystyrene-Calcium Phosphate Nanocomposites: Preparation, Morphology, and Mechanical Behavior

Calcium phosphate nanoparticles were prepared by matrix-mediated synthesis and were characterized using X-ray diffraction and transmission electron microscopy techniques. The particle size was found to be around 10 nm. Nanocomposites of polystyrene with calcium phosphate were prepared by a melt mixing technique. Mechanical properties of the nanocomposites such as tensile strength, tensile modulus, elongation at break, and impact strength were determined. Tensile strength and modulus showed 50 and 80% increase for 5% filled composites, respectively. Careful differential scanning calorimetric measurements were performed to evaluate the changes in heat capacity (C(p)) as a function of filler loading. The Delta C(p) values decreased dramatically as a function of filler loading indicating the existence of strong interaction between the nanofiller and polystyrene. A three-phase model consisting of a rigid amorphous phase has been proposed to illustrate the strong polymer-filler interaction.