Renewable biopolymers are important feedstocks for developing sustainable materials to address the global climate change. As the most abundant biomass on earth, cellulose and its derivatives can play a critical role in manufacturing the second generation biofuels, biopolymers, and biochemicals. This paper reports our research in developing biodegradable polymer blends containing a cellulose ester and a biodegradable polyester. A series of cellulose acetate butyrate (CAB) and poly(butylene adipate terephthalate) （PBAT）blends ranging from 20% to 80% by weight of CAB were prepared by a melt extrusion process. It was found that CAB and PBAT had good compatibility over the composition range, exhibiting a single glass transition temperature (Tg). The crystallization of PBAT was suppressed by the presence of 50% or more CAB. The blends containing from 35% to 65% of CAB unexpectedly had better thermal stability than pure CAB or PBAT. The CAB/PBAT blends showed unexpected and interesting rheological properties, the blends showed up to 34% reduction in melt viscosity at a shear rate of 100 s<sup>-1 </sup>and up to 32% viscosity reduction at 1363 s<sup>-1</sup>. The change in melt rheology has improved the melt processability of CAB for a broad range of applications requiring low viscosity. The films made from the polymer blends containing 80%, 65% and 50% of CAB had low ductility (26% to 57% Elongation at Break) and high modulus (585 to 1080 MPa), these blends also had low melt elasticity. The ductility of the films increased with the PBAT content, reaching 250% at 80% of PBAT. The melt ductility of the CAB/PBAT blends were also significantly improved over that of pure CAB, enabling successful fiber spinning from the CAB/PBAT blends. The results of this research have demonstrated the potential to develop materials from cellulose derivatives having processability and mechanical properties in the range of typical synthetic polymers, this provides a technical foundation for the development of these cellulose-based polymer blends for sustainable packaging and other applications.

Cellulose ester and biodegradable polyester blends having improved properties

255th National Meeting (2018)

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