Graphene morphology effect on the gas barrier, mechanical and thermal properties of thermoplastic polyurethane

In this study, we investigated the effect of the morphology of few-layer (FLG) and multi-layer (MLG) graphene flakes on the gas barrier properties of thermoplastic polyurethane (TPU) films. Composite films of TPU filled with FLG and MLG at different concentrations are prepared by solution blending-casting and hot-pressing, achieving an in-plane alignment of the fillers and, consequently, improving the gas barrier properties. Specifically, the hot-pressed TPU composites loaded with 4 wt% of the MLG with a lateral size distribution of 0.1-25.0 mu m demonstrates a reduction of similar to 81% in the gas permeability compared to the pristine TPU. Additionally, the thermal conductivity of the TPU composite (loaded with 4 wt% of MLG) is enhanced similar to 3 times and the Young modulus increases more than 5 times compared to the pristine TPU.