Simultaneous improvement of mechanical properties and thermal stability of bacterial polyester by cellulose nanocrystals.

ABSTRACT

Green nanocomposites were prepared by adding well-dispersed cellulose nanocrystals (CNCs) into bacterial polyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) matrix. Simultaneous enhancements on the mechanical property and thermal stability of PHBV after reinforcement of CNCs were achieved. Compared to neat PHBV, a 149% improvement in tensile strength and 250% increase in Young's modulus can be obtained for the resulting nanocomposites with 10 wt.% CNCs, more importantly, the T0, T5%, Tmax and Tf increased by 51.4, 36.5, 47.1 and 52.9°C, respectively. This was due to a combination of CNCs reinforcement in the polymeric matrix, and especially the formation of strong intermolecular hydrogen bonding interactions through achieving the excellent dispersion of CNCs in the PHBV matrix via the solvent exchange procedure, as a result, the formation of six-membered ring ester during the degradation process of PHBV was clearly suppressed.