Narrow Results

Biodegradable composite films based on chitosan and lignin with various composition were prepared via the solution-casting technique. FT-IR results indicate the existence of hydrogen bonding between chitosan and lignin, and SEM images show that lignin could be well dispersed in chitosan when the content of lignin is below 20 wt% due to the strong interfacial interaction. As a result of strong interaction and good dispersion, the tensile strength, storage modulus, thermal degradation temperature and glass transition temperature of chitosan have been largely improved by adding lignin. Our work provides a simple and cheap way to prepare fully biodegradable chitosan/lignin composites, which could be used as packaging films or wound dressings.

Low density polyethylene (LDPE)/lignin blends were prepared using melt blending. Two kinds of compatibilizers, ethylene-vinylacetate (EVA) which is softer than LDPE and polyethylene grafted with maleic anhydride (PE-g-MA) which is harder than LDPE were used to improve the interfacial adhesion. Scanning electron microscope (SEM) was used to investigate the dispersion of lignin in LDPE matrix. The results showed that both of the compatibilizers could improve the interaction between the low density polyethylene and lignin. However, the effects of the two compatibilizers on the mechanical properties of LDPE/lignin blends were different. The elongation at break of the blends was obviously increased by adding EVA, while significant improvement of tensile strength was observed by adding PE-g-MA. Several theoretical models have been used to further analyze the experimental data, combined with the morphological observation of tensile fractured surfaces by SEM.