Improvement Approach for Gas Barrier Behavior of Polymer/Clay Nanocomposite Films
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Improvement Approach for Gas Barrier Behavior of Polymer/Clay Nanocomposite Films Maedeh Dabbaghianamiri1,2, Sayantan Das1, 2, and Gary W. Beall 1, 2 1
Materials Science Engineering and Commercialization Program, Texas State University, TX 78666, U.S.A. 2
Department of Chemistry and Biochemistry, Texas State University, TX 78666, USA
ABSTRACT Polymer nanocomposites (PNC) include a copolymer or polymer which has nanoparticles dispersed in the polymer matrix at the nano-level. One of the most common types of polymer nanocomposites contain smectic clays as the nanoparticles. These clay minerals increase the mechanical properties of standard polymers and improve barrier properties. For optimum barrier properties, Layer-by-Layer assembly (LbL) is one of the most effective methods for depositing thin films. LbL methods however, are quite tedious and produce large quantities of waste. A newly discovered phenomenon of self-assembled polymer nanocomposites utilizes entropic forces to drive the assembly to spontaneously form a larger nanostructured film. This approach allows polymers and nanoparticles with high particle loadings to be mixed, and create the super gas barrier films. We have developed a coating technique which can be employed to make selfassembled gas barrier films via inkjet printing. This technique is industrially scalable and efficient. This is because it does not need any rinsing step and drying steps as required in LbL. The influence of different polymers Polyvinylpyrrolidone (PVP) and Poly (acrylic acid) PAA with Montmorillonite (MMT) nanoclay solutions on Polyethylene terephthalate (PET) substrate is examined to study their effectiveness as a gas barrier film. The results showing the excellent oxygen barrier behavior of a combination of PVP and MMT Nano clay nanocomposite with high transparency. These high barrier gas nanocomposite films are good candidates for a variety of food packaging applications. INTRODUCTION The LbL self-assembly fabrication method allows the design of multilayer ultrathin films. For the first time in 1992, Decher and Hong [1] introduced this spontaneous adsorption of nanoparticles. For producing ordered structure spontaneously, self-assembly often involves the use of surfactants or block copolymers as soft templates. Nanocomposites have been introduced in response to a growing need in surface coatings for the biomedical, microelectronics, and flexible packaging industries. In the packaging industry, according to recent assessments [2], it is predicted in 2022 the global market size of flexible packaging will be $293 billion [3]. Currently there is a high level of research focused on the preparation of LbL barrier films with different coating materials and high gas-barrier properties of these flexible films have been studied for packaging applications [4]. In traditional ways for making gas barrier films, a substrate is dipped in solutions of polymer repeatedly followed by platy nanoparticle dispersions to create many alternating organic/inorganic layers (usually more than 50).
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