Synergistic reinforcing effect of nano-montmorillonite and cellulose nanocrystals on poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Abstract

The montmorillonite/cellulose nanocrystal/poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) ternary nanocomposites were prepared by using 1 wt% CNCs and various amounts MMT. A synergistic enhancement was found between MMT, CNCs and PHBH. Intermolecular interactions occurred between O–H of MMT, O–H of CNCs and C=O of PHBH. Scanning electron microscopy (SEM) reveals that the compatibility of nanocomposites is the best with 3 wt% MMT content. It can be suggested that putting MMT into CNC-PHBH (CP) binary nanocomposites forms intercalation structures based on the XRD pattern. Thermogravimetric analysis shows that the thermal degradation temperature of nanocomposites is improved to 236.14 °C on dispersing 3 wt% MMT. Differential scanning calorimetry and polarizing optical microscopy suggest that MMT improves the crystallinity of nanocomposites, thus proving the good nucleation performance of MMT as a nucleating agent. Meanwhile, the mechanical properties of nanocomposites are also improved. The elastic modulus of nanocomposites improves by 53.5% compared with CP. With the addition of 5 wt% MMT, water vapor transmission rate and oxygen transmission rate reach 30.74 g/m2 day and 34.82 cm3/m2 day respectively, which satisfies the preservation conditions of meat packaging.