Valorization of Kraft Lignin and Corn Cob by-Products into PLA-Matrix based Biocomposites: Characterisation of Injected-moulded Specimens

The goal of this exploratory work was to evaluate the influence of two industrial by-products - Kraft lignin from forestry sector, and corn cobs from the French agricultural sector - on biocomposites properties. Several blends involving Kraft lignin and/or corn cob in a PLA matrix were compounded within Valagro Recherche French company. By incorporating 20 % (w/w) of by-products into a PLA matrix, the price of the developed biocomposites is expected to be lower than a PLA-made product. Granulates were injected for further characterizations such as flexural mechanical properties, hardness, thermal properties, surface tension, FT-IR spectroscopy, and density. Incorporation of corn cob and Kraft lignin increased flexural modulus of biocomposites to 3.7 GPa. Flexural strength was not drastically impacted since values ranged around 70 –85 MPa. It was also observed an increase of biocomposites hardness with Kraft lignin rather than corn cob. DSC thermograms did not reveal any influence of the by-products on glass transition temperature of PLA.The present product is a thermoplastic material, entirely bio-based, biodegradable, and it was obtained from simple formulation without any use of harmful solvent