Enhanced moisture barrier films based on EVOH/exfoliated graphite (EGn) nanocomposite films by solution blending

A series of ethyl-vinyl alcohol (EVOH) nanocomposite films with exfoliated graphite nanosheets (EGn) were prepared via a solution blending method and their physical and moisture barrier properties were investigated as a function of the EGn content. The physical properties were strongly dependent upon the chemical and morphological structures originating from the differences in EGn composition. The nanocomposite films showed no strong interactions between the polymer and EGn filler, and this resulted in poor dispersion in relatively high content EVOH/EGn nanocomposites. With increasing content of EGn particles, the water vapor transmission rate varied in the range of 1.29 to 3.14 cc/m2/day and the water uptake greatly decreased from 9.1 to 3.4 wt%. The water resistance capacity of EVOH was greatly enhanced and moisture diffusion in the pure EVOH film was retarded by introducing the EGn. However, thermal stabilities were not improved by incorporating EGn due to the poor interaction between EVOH polymer chains and the EGn surface. Open image in new window