Influence of Hybrid Cellulose/Bentonite Fillers on Structure, Ambient, and Low Temperature Tensile Properties of Thermoplastic Starch Composites

Thermoplastic starch (TPS) composites incorporating bentonite/cellulose (Bent/Cellulose) hybrid fillers in different ratios were prepared by film casting. Ultra-sonication was done to promote good dispersion of filler in the host TPS and enhance the filler-matrix interactions. Ultra-sonicated fillers resulted in superior improvement in the tensile properties when the samples preconditioned at both ambient and 2 degrees C. Upon preconditioning at 2 degrees C, the TPS composite containing the ultra-sonicated hybrid bent/cellulose in 80:20 ratio displayed the greatest tensile properties achievement among all the tested materials. These could be due to the effect of low temperature interactions between the starch, plasticizers, and the hybrid fillers. Differential scanning calorimetry analysis proved the changes in the crystallinity and dynamic characteristic of the TPS molecular chains which benefit in enhancing the biopolymer elongation at break and toughness, even when stored at refrigerated condition. In summary, the TPS/bent/cellulose composite has potential to be further developed for refrigerated food packaging application. POLYM. ENG. SCI., 2020. (c) 2020 Society of Plastics Engineers