Improving the gas barrier, mechanical and thermal properties of poly(vinyl alcohol) with molybdenum disulfide nanosheets

Abstract

New multifunctional materials with both high structural and gas barrier performances are important for a range of applications. Herein we present a one‐step mechanochemical process to prepare molybdenum disulfide (MoS2) nanosheets with hydroxy functional groups that can simultaneously improve mechanical strength, thermal conductivity, and gas permittivity of a polymer composite. By homogeneously incorporating these functionalized MoS2 nanosheets at low loading of less than 1 vol %, a poly(vinyl alcohol) (PVA) polymer exhibits elongation at break of 154%, toughness of 82 MJ/m3, and in‐plane thermal conductivity of 2.31 W/m K. Furthermore, this composite exhibits significant gas barrier performance, reducing the permeability of helium by 95%. Under fire condition, the MoS2 nanosheets form thermally stable char, thus enhancing the material's resistance to fire. Hydrogen bonding has been identified as the main interaction mechanism between the nanofillers and the polymer matrix. The present results suggest that the PVA composite reinforced with 2D layered nanomaterial offers great potentials in packaging and fire retardant applications. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 406–414

Multifunctional Role of MoS2 in Preparation of Composite Hydrogels: Radical Initiation and Cross-Linking

“…In particular, soft, nanocomposite hydrogels have benefited from the elastic, cross-linked networks that confine a considerable amount of water and additive nanomaterials that induce tailored, complex properties, and now hold privileged positions in the development of smart, elastic materials. − Typically, colloidal nanoparticles including nanowires or carbon dots have been widely used, − and more recently, two-dimensional layered materials such as ceramic nanosheets, carbides, graphene oxides, and covalent organic framework have been extensively researched. − They have relatively weak intermolecular interactions between the layers and thus show large surface areas and accessible active sites that are exposed on the surface, which imparts sophisticated yet essential properties to the polymeric networks. , Among many layered materials, molybdenum disulfide (MoS 2 ) has been incorporated in hydrogel networks due to its mechanical or electronic properties; recently, the embedded hydrogels have been used as a functional platform for energy-related or environmental applications such as separation or catalysis under aqueous conditions. − When designing the materials via a bottom-up approach, MoS 2 and other monomeric components are dispersed on a molecular level; thereafter, the composite networks are set, usually, by radical polymerization while leaving the inorganic material as an exogenous additive in most cases. Conversely, from the perspective of polymer chemistry, the chemical function of MoS 2 that can play a significant role as a reactive component in the formation of hydrogels through radical polymerization has been rarely investigated.…”

Chemically modified carbon nanostructures and 2D nanomaterials for fabrics performing under operational tension and extreme environmental conditions

“…99 Finally, a rare report describes promising enhancement of the UV-blocking properties of a polymer matrix upon modification with hydroxyl-functionalized MoS 2 nanosheets. 100 Specifically, the MoS 2 -based nanofiller offers enhanced UV-absorbance mainly in the UV-B and UV-C regions, directly proportional to the MoS 2 loading in the composite material. Even though interesting, the incorporation of functionalized MoS 2 on polymeric fabric fiber and its effect on the UV transmittance are yet to be comprehensively assessed.…”

Stretchable gas barrier films achieved by hydrogen‐bond self‐assembly of nano‐brick multilayers

“…Conventional alumina/zinc oxide coatings display excellent barrier properties but are easy to break or crack when the barrier films are stretched. Although pure polymer materials such as ethylene/vinyl alcohol copolymer (EVOH), polyvinyl alcohol (PVA), and polyvinylidene chloride (PVDC) can meet the requirement of general packaging application, they cannot be applied to high barrier fields 6–12 . Besides, such polymer materials have limited application range due to their humidity sensitivity and poor mechanical strength.…”