Mechanical and thermal properties of compatibilized composites of polyethylene and esterified lignin

Lignin have been esterified using phthalic anhydride and then blended with (up to 40 wt.%) low density polyethylene (LDPE). Maleic anhydride grafted LDPE has been added as compatibilizer. The mechanical and thermal properties of the blends were measured according to ASTM standards and compared with those of neat LDPE. The results reveal that addition of compatibilizer improved the mechanical properties significantly approaching values close to those of neat LDPE. The scanning electron micrographs of the blend specimens also support the above observations. Thermogravimetric analysis showed greater thermal stability for the compatibilized blends. The char content has been found to increase with increasing filler (lignin phthalate) content. DSC analysis revealed that the crystallinity values of the blends slightly increase by the addition of filler (lignin phthalate).