https://cyberleninka.org/article/n/1018032.pdf

Polymer nanotechnology: Nanocomposites

Permeability of polymer/clay nanocomposites: A review

Gas barrier performance of graphene/polymer nanocomposites

Due to its exceptionally outstanding electrical, mechanical and thermal properties, graphene is being explored for a wide array of applications and has attracted enormous academic and industrial interest. Graphene and its derivatives have also been considered as promising nanoscale fillers in gas barrier application of polymer nanocomposites (PNCs). In this review, recent research and development of the utilization of graphene and its derivatives in the fabrication of nanocomposites with different polymer matrices for barrier application are explored. Most synthesis methods of graphene-based PNCs are covered, including solution and melt mixing, in situ polymerization and layer-by-layer process. Graphene layers in polymer matrix are able to produce a tortuous path which works as a barrier structure for gases. A high tortuosity leads to higher barrier properties and lower permeability of PNCs. The influence of the intrinsic properties of these fillers (graphene and its derivatives) and their state of dispersion in polymer matrix on the gas barrier properties of graphene/PNCs are discussed. Analytical modeling aspects of barrier performance of graphene/PNCs are also reviewed in detail. We also discuss and address some of the work on mixed matrix membranes for gas separation.

Gas Barrier Performance of Graphene/Polymer Nanocomposites

Currently, there is great interest in graphene-based devices and applications because graphene has unique electronic and material properties, which can lead to enhanced material performance. Graphene may be used in a wide variety of potential applications from next-generation transistors to lightweight and high-strength polymeric composite materials. Graphene, which has atomic thickness and two-dimensional sizes in the tens of micrometer range or larger, has also been considered a promising nanomaterial in gas- or liquid-barrier applications because perfect graphene sheets do not allow diffusion of small gases or liquids through its plane. Recent molecular simulations and experiments have demonstrated that graphene and its derivatives can be used for barrier applications. In general, graphene and its derivatives can be applied via two major routes for barrier polymer applications. One is the transfer or coating of few-layered, ultrathin graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), on polymeric substrates. The other is the incorporation of fully exfoliated GO or rGO nanosheets into the polymeric matrix. In this article, we review the state-of-the-art research on the use of graphene, GO, and rGO for barrier applications, including few-layered graphene or its derivatives in coated polymeric films and polymer nanocomposites consisting of chemically exfoliated GO and rGO nanosheets, and their gas-barrier properties. As compared to other nanomaterials being used for barrier applications, the advantages and current limitations are discussed to highlight challenging issues for future research and the potential applications of graphene/polymer, GO/polymer, and rGO/polymer composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39628.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/app.39628

Graphene and graphene oxide and their uses in barrier polymers

Gas barrier properties of butyl rubber/vermiculite nanocomposite coatings

Barrier coating mixtures include (a) a non-butyl elastomeric polymer; (b) an acid or base treated dispersed, substantially exfoliated silicate filler material that has not been functionalized with organic cations having an aspect ratio greater than 25; and (c) at least one additive, wherein the total solids content is less than 30% and the amount of filler is between 5% to about 60% of the total solids content. The coating retains its permeability properties under strain and has a strain to first damage of at least 5% biaxial elongation at 0% RH. Coated articles, free standing films and membranes, which are flexible and elastomeric, are produced using the barrier coating mixtures. Methods of 15 manufacturing of such coated products are also encompassed.

Barrier coating of a non-butyl elastomer and a dispersed layered filler in a liquid carrier and coated articles

Barrier coating mixtures contain in a carrier liquid, (a) an elastomeric (preferably butyl-containing) polymer; (b) a dispersed exfoliated layered filler having an aspect ratio greater than 25; and (c) at least one surfactant, wherein the solids content of the mixture is less than 30% and the ratio of polymer (a) to filler (b) is between 20:1 and 1:1. Coated articles, which are rigid or flexible and elastomeric, and free-standing films and membranes, which are flexible and elastomeric, are produced using the barrier coating mixtures.

Barrier coating of an elastomer and a dispersed layered filler in a liquid carrier

A multilayer barrier structure includes a plurality of relatively thin nanocomposite layers separated by one or more relatively thick intermediate layers selected from synthetic elastomers or non-elastomeric polymers. The composites exhibit remarkably long breakthrough and lag-times and are useful for packaging or protective apparel.

Multilayer nanocomposite barrier structures

Barrier coating mixtures contain in a carrier liquid, (a) a non-elastomeric polymer; (b) an exfoliated layered platelet-like silicate filler which may or may not have been acid or base treated that has not been functionalized with organic cations having an aspect ratio greater than 25; and (c) at least one additive, wherein the total solids content is less than 30% and the amount of filler is between 5% to about 60% of the total solids content. Coated articles and containers, freestanding films and packaging films are produced using the barrier coating mixtures. Methods of manufacturing such coated products are also encompassed.

Carrie A. Feeney

Papers

Gas barrier properties of butyl rubber/vermiculite nanocomposite coatings

Barrier coating of a non-butyl elastomer and a dispersed layered filler in a liquid carrier and coated articles

Barrier coating of an elastomer and a dispersed layered filler in a liquid carrier

Multilayer nanocomposite barrier structures

Barrier coating of a non-elastomeric polymer and a dispersed layered filler in a liquid carrier and coated articles