Macadamia Nutshell Powder Filled Poly Lactic Acid Composites with Triacetin as a Plasticizer

Biocomposites were successfully prepared from polylactic acid (PLA) and macadamia nutshell powder as filler. To improve the interfacial adhesion between the matrix and the macadamia nutshell powder, mandelic acid was incorporated as an amphiphilic additive. Different amount of triacetin was added to plasticize the PLA and thereby reduce the brittleness of the biocomposite samples. Structural and thermal characterizations of the biocomposites were performed by Fourier transform infrared spectroscopy, differential scanning calorimetry and thermo-gravimetric analysis. Thermo-mechanical characterization of the biocomposites was carried out on a dynamic mechanical analyzer. Mechanical properties and the water uptake studies of the biocomposites have been reported. The results indicated that at 8 wt.% of plasticizer, the biocomposites showed maximum tensile strength of similar to 11 MPa as well as appreciable elongation at break. Morphological studies of the biocomposites samples at different amounts of plasticizer were also carried out by scanning electron microscope.