Enhanced Mechanical Properties of Biodegradable Polybutylene Adipate-Co-Terephthalate Blended with Cellulose Nanofiber Modified with Silica Nanoparticles

Polyethylene (PE) mulching films are widely used in crop fields. However, residual PE films have been accumulated in the soil reducing crop yield. It has been tried that PE films are replaced by biodegradable polymers such as Polybutylene adipate-co-terephthalate (PBAT). In order to increase the use of PBAT mulching films, problems such as its low mechanical properties, short degradation period and low UV resistance still need to be addressed. In this study, through a sol-gel reaction, silica nanoparticles were synthesized on the surface of the cellulose nanofiber (CNF) to have a bumpy surface. The surface-modified CNF (s-CNF) could be obtained in powder form after drying because aggregation due to capillary force between the fibers is suppressed. s-CNF was well-dispersed in PBAT or PBAT/PLA blends using a melt-mixer. The mechanical properties of the composite films were improved, for example, tensile strength at break was enhanced by 35% with 3wt% s-CNF addition. The mechanical property was systematically studied in terms of s-CNF and PLA contents. Controlling silica particle content and morphology will be presented. The degradation rate and UV resistance of the composite films may also be presented.