Sustainable Poly(butylene adipate-co-furanoate) Composites with Sulfated Chitin Nanowhiskers: Synergy Leading to Superior Robustness and Improved Biodegradation

Plastic waste accumulation is a current societal crisis. Although replacing nondegradable plastics with biodegradable alternatives is one solution to this problem, conventional biodegradable plastics have low mechanical performance and require fastidious decomposition conditions. Consequently, fulfilling the industrial requirements of processability, end-use applicability, and post-use biodegradability is difficult. Therefore, integrating mechanical robustness and enhanced degradability into a single material is critical. Herein, we introduce a fully biomass-derived poly(butylene adipate-co-furanoate) (PBAF) composite with sulfated chitin nanowhiskers prepared by in situ polymerization. This approach efficiently disperses the nanofiller in the polymer matrix and creates beneficial interactions between the nanofiller and the furan rings of the polymer, resulting in excellent material properties. A PBAF composite film loaded with 0.1 wt % nanofiller is as strong as a nondegradable engineering plastic (i.e., poly(ethylene terephthalate)) and exhibits higher tensile strength (1.6-fold), tear toughness (1.4-fold), and degradation rate (1.7-fold) than neat PBAF. A structure–performance relationship study revealed that the nanofiller is accommodated close to the furan rings of the polymer, which results in noticeable segmental mobility and structural change, whereas the benzene rings of conventional poly(butylene adipate-co-terephthalate) show negligible change due to its sturdy crystalline phase. The developed all-organic composite is a sustainable alternative to conventional plastics.