MELT COMPOUNDING OF POLY (3-HYDROXYBUTYRATE-CO-3-HYDROXYVALERATE) (PHBV) / NANOFIBRILLATED CELLULOSE (NFC) NANOCOMPOSITES: PROPERTIES AND SOLUBILITY OF CARBON DIOXIDE

摘要

Biodegradable nanocomposites were prepared using nanofibrillated cellulose (NFC) as the reinforcement and poly (3-hydroxybutyrate-co-3-hydroxyvalerate, PHBV) as the polymer matrix. PHBV powder was dispersed in water, mixed with an aqueous suspension of NFC fiber, and freeze dried. The resulting PHBV/15 wt% NFC was then used as a masterbatch in a subsequent melt compounding process to produce nanocomposites of various formulations. Its properties, such as mechanical properties, crystallization behavior and solubility of carbon dioxide (CO2), were evaluated. Scanning electron microscopy (SEM) images revealed that individual fibers with diameters less than 1 um were still clearly distinguishable even though some of the NFC agglomerated. Adding NFC increased the tensile modulus of the PHBV/NFC nanocomposites nearly twofold. Differential scanning calorimetry (DSC) analysis showed that the NFC served as a nucleating agent, promoting the early onset of crystallization. However, high NFC content also led to greater thermal degradation of the PHBV matrix. The solubility of CO2 in the PHBV/NFC nanocomposites decreased and the desorption diffusivity increased as more NFC was added.