Sulfonated Poly(butylene Adipate-<i>co</i>-terephthalate)/Sodium Montmorillonite Nanocomposite Films with an Ultra-High Oxygen Barrier
Dereje Kebebew Debeli, Fangfang Huang, Linbo Wu
Abstract
Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable polymer very suitable for film applications. However, its low oxygen and water vapor barrier performance limit its applications in some high-demanding fields. Herein, we report PBAT-based nanocomposite films with an ultra-high oxygen barrier prepared by exfoliating a large amount of Na-montmorillonite (MMT) in a water-dispersible sulfonated PBAT copolyester matrix. At a MMT volume percentage (Φm) of 9–22 vol %, the MMT was highly oriented and the volume fraction dependence of oxygen permeability (PO2) of the films can be well described by the Bharadwaj model. At higher MMT loadings of 28–32 vol %, a network-like MMT morphology was formed and the PO2 value was even lower than that predicted by the model. The nanocomposite film (NCF) with 32 vol % MMT exhibited a PO2 value of 7.5 × 10–16 cm3 cm cm–2 s–1 Pa–1 and a water vapor permeability of 1.57 × 10–11 g m m–2 s–1 Pa–1. Compared to PBAT, the oxygen barrier was improved by 2 orders of magnitude.