Enhanced mechanical and barrier properties of polyurethane nanocomposite films with randomly distributed molybdenum disulfide nanosheets

Lithium intercalated molybdenum disulfide (LixMoS2) was synthesized using a simple one-step solvothermal technique, followed by the formation of few-layer suspension of chemically exfoliated molybdenum disulfide (c-MoS2) in aqueous solution. The c-MoS2 was introduced into the waterborne polyurethane (WPU) emulsions to obtain the nanocomposite films by a simple blending method. As a comparison, MoS2/WPU composite film was prepared by directly blending bulk MoS2 particles into WPU. The incorporation of chemically exfoliated MoS2 significantly enhanced the thermal stability and mechanical properties of WPU film: with the incorporation of 4 wt% of c-MoS2, the 5% mass loss temperature of WPU nanocomposite film was increased by 30 °C relative to neat WPU; the tensile strength and Young's modulus were increased by 140% and 85%, respectively. Furthermore, the moisture permeability coefficient was reduced by about 37% at a MoS2 content of 4 wt%. These results demonstrate that such a facile and rapid technique presented herein will provide an effective and promising strategy to design and fabricate high barrier MoS2/polymer nanocomposite films.