Thermo-mechanical response of poly (lactic acid)/hydroxyapatite nanocomposites: Observations and modeling within the overstress concept

Experimental investigation and constitutive modelling are conducted of the mechanical response of poly (lactic acid) (PLA)/hydroxyapatite (HA) nanocomposites at temperatures ranging from room temperature up to 50 °C. PLA is a biodegradable and biocompatible polymer widely used in medical applications. To enhance its mechanical properties, PLA is reinforced with hydroxyapatite. This work focuses on the effects of temperature and strain rate on the mechanical behaviour of PLA/HA composites under tension. Observations show that the presence of filler reduces tensile strength, but results in an increase in Young's modulus and elongation to break. The response of composites is brittle at room temperature, and it becomes ductile at elevated temperatures. The influence of temperature and strain rate is adequately described by the viscoplasticity model based on overstress (VBO).