Mechanical and rheological behavior of highly filled polystyrene with lignin

The mechanical, rheological, and morphological properties of polystyrene (PS)/lignin blends over a wide range of lignin content (0-80 wt%) have been studied in this work. PS/lignin blends were compounded in an internal batch mixer with and without the addition of a linear triblock copolymer based on styrene, ethylene, and butylene (SEBS). A morphological analysis was carried out by scanning electron microscopy to determine the state of dispersion and the interfacial adhesion between the lignin particles and the PS matrix. It was found that the flexural and torsion moduli both increased, while the tensile properties decreased with increasing lignin content. Nevertheless, compatibilizer addition was found to improve the tensile properties of the lignin/PS blend. The shear rheological behavior of the lignin/PS blends was also studied in this work where viscosity, dynamic moduli, and activation energy were found to be very sensitive to both lignin and compatibilizer contents. POLYM. COMPOS., 33: 353- 361, 2012. (c) 2012 Society of Plastics Engineers