Lignin-Based Polyethylene Films with Enhanced Thermal, Opacity and Biodegradability Properties for Agricultural Mulch Applications

Lignins are promising alternative raw materials for biocomposites due to their renewability, low cost and abundance. In this work, the use of (softwood and hardwood) Kraft lignins in the development of LLDPE/lignin films for agricultural mulch applications is studied. Processable blends were obtained from unmodified softwood lignin (SW) and from hardwood lignin modified by esterification (HWE). LLDPE was pelletized with (2.5%, 5% and 10%) lignin with particle size between 38 and 75 mu m and flexible films were blown extruded. Processable extrusion blends showed temperature differences lower than 20 degrees C between the Tg of lignin and the melting temperature of LLPDE. Films from neat LLPDE and with 2.5% of HWE and up to 5% SW exhibited statistically comparable ( approximately equal to 349%) values of ductility. Ester groups present in lignin improve weight loss of lignin-based blends after soil buried test.