Graphene oxide–polyoctahedral silsesquioxane–chitosan composite films with improved mechanical and water-vapor-transport properties

Graphene oxide (GO) and ball-milled maleamic acid–isobutyl polyoctahedral silsesquioxanes (MAIPSs) were incorporated simultaneously into chitosan (CS) via solution blending to evaluate their combined effects on the structures and properties of composite films. GO and MAIPS aggregates were homogeneously dispersed in CS and affected the crystallinities of the composite films. The binary addition of GO and MAIPS resulted in synergistic enhancements of the tensile strength and elongation at break of the composite films. Composite films containing 3% w/w MAIPS and 0.25% w/w GO (CS–GO–MAIPS-3) exhibited the highest strength and modulus, which were 48 and 42.2% higher, respectively, than the values of the CS film. The water-vapor-sorption isotherms revealed that monolayer sorption sites decreased with the addition of GO or/and MAIPS, but the dissolution process was not significantly influenced. The water-vapor permeability reached its lowest value for the CS–GO–MAIPS-3 film because of hindered diffusion with the presence of impermeable nanoparticles. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47748.