The 3rd International Symposium on Nanocellulosic Materials (3rd ISNCM)

    Bio-degradable polymer composites have attracted great interest in replacing traditional petroleum-based polymers. Poly (butylene adipate-co-terephthalate)(PBAT) composites have broad application prospects in the fields of food packaging, garbage bags, and agricultural mulch. Cellulose nanofibers (CNF) can be used to strengthen PBAT composites, but their compatibility is poor. In order to improve the compatibility of CNF and PBAT, octadecylamine (ODA) was used to modify CNF (OCNF) and the degree of substitution was calculated. The morphology, FTIR spectroscopy, thermogravimetric analysis, and water contact angle of CNF before and after modification were measured. Subsequently, CNF/PBAT composites were prepared by a micro twin-screw extruder and a micro injection molding machine, and their mechanical properties, thermal stability, and fracture surface morphology were characterized and tested. The results of the thermogravimetric analysis showed that the thermal stability of CNF was improved after modification, and the maximum thermal degradation temperature was increased from 335℃ to 360℃. The water contact angle test results show that the hydrophobicity of the modified CNF is significantly improved. The water contact angle of CNF increased from the initial 57.3° to 109.1°. Furthermore, CNF can be fully dispersed in dichloromethane after modification. Compared with the unmodified CNF/PBAT composites, the tensile strength and elongation at break of OCNF/PBAT composites increased by 43.6% and 53.9% when 1 wt% OCNF was added, indicating that the mechanical properties of the composites were significantly enhanced. Moreover, the mechanical properties of OCNF/PBAT composites show a trend of first increasing and then decreasing with the increase of CNF substitution degree. It can be concluded that the surface modification of CNF with ODA is an effective method to improve the compatibility of CNF with PBAT.