Thermal, mechanical, and rheological properties of graphite- and graphene oxide-filled biodegradable polylactide/poly(ɛ-caprolactone) blend composites

The effect of graphite (G) and graphene oxide (GO) dispersions on the thermal, mechanical, rheological properties of biodegradable polylactide (PLA)/poly(ɛ-caprolactone) (PCL) blend composites has been comparatively investigated. Surface morphology analysis indicates that the degree of morphological stability depends on not only the loading of the filler but also enthalpic interaction between the filler surface and the polymer blend. A significant improvement in the elongation at break (43.8%), with well-balance of modulus and strength characteristics, is observed for the G-filled (0.25 wt %) blend composite, whereas the GO-filled (0.05 wt %) ternary composite shows a strong (∼19 °C) improvement in the thermal stability. Furthermore, the dynamic modulus of the blends increased after composite formation; however, the degree of improvement is greater for the G-filled blend composites. On the basis of the obtained results, we propose a general description of how the morphology and structure of the blend composites are related to the final properties.