Preparation and characterization of formaldehyde-modified black liquor lignin/poly (propylene carbonate) composites

In this paper, the black liquor lignin (BL) from pulp and paper industry was chemically modified using formaldehyde to adjust its aggregation structure and dispersion behavior. The properties of the formaldehyde-modified black liquor lignin (BLF) were measured by Fourier transform infrared spectroscopy, transmission electron microscopy, and differential scanning calorimetry. Results indicated that the BLF had better dispersion ability than BL. Therefore, the BLF as reinforcing fillers was incorporated into poly(propylene carbonate) (PPC) by melt compounding to prepare biodegradable BLF/PPC composites. The tensile properties, microstructure, thermal decomposition properties, and rheological properties of the BLF/PPC composites were investigated. Results showed that the performance of composites was depend on the dispersion of BLF. After adding a small amount of BLF into PPC, the tensile strength, tensile modulus, thermal stability, and processing stability of the composite were significantly improved.