Effect of WS2 inorganic nanotubes on isothermal crystallization behavior and kinetics of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

Nanocomposites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and tungsten disulfide inorganic nanotubes (INT-WS) were prepared by blending in solution, and the effects of INT-WS on the isothermal crystallization behavior and kinetics of PHBV were investigated for the first time. The isothermal crystallization process was studied in detail using various techniques, with emphasis on the role of INT-WS concentration. Differential scanning calorimetry (DSC) and polarized optical microscopy (POM) showed that, in the nucleation-controlled regime, crystallization rates of PHBV in the nanocomposites are influenced by the INT-WS loading. Our results demonstrated that low loadings of INT-WS (0.1-1.0 wt %) increased the crystallization rates of PHBV, reducing the fold surface free energy by up to 24%. This is ascribed to the high nucleation efficiency of INT-WS on the crystallization of PHBV. These observations facilitate a deeper understanding of the structure-property relationships in PHBV biopolymer nanocomposites and are useful for their practical applications.This work was supported by the Spanish Ministry Economy and Competitivity (MINECO), Projects MAT2013-41021-P and MAT2017-84691-P. Mohammed Naffakh would also like to acknowledge the MINECO for a ‘Ramón y Cajal’ Senior Research Fellowship.Peer Reviewe