Investigating competition of strong interfacial interaction and chain scission in PBAT/EVOH/GO composite by rheological measurements

The blends of poly(butylene-adipate-co-terephthalate)/poly(ethylene-vinyl alcohol) (PBAT/EVOH) with varying amounts of graphene oxide (GO) were prepared by melt mixing. The localization of GO in PBAT and at the interface was confirmed by morphological evaluation. The dual effect of GO in degradation of PBAT phase and interface improvement of PBAT/EVOH was examined by rheological measurements and models. The results showed that the improved interfacial interaction induced by GO dominates its degradation effect in PBAT. Rheological analysis revealed that the interfacial elasticity originating from GO dominates the total elasticity of the system, resulting in an increase in the final elasticity. Generalized Fractional Zener (GFZ) model was used to analyze elasticity of the polymer blend and its nanocomposites with a well fit to the experimental results. Also, the Lee–Park model was used to distinguish the effects of particle interactions as well as interface strengthening from deterioration of matrix modulus due to PBAT degradation by GO. The increased elasticity of the interface showed that the strengthening effect of GO at the interface overcomes its degradation effect. Also, the application of Coran model to analyze phase homogeneity revealed a linear increase in interfacial interaction with GO concentration.