Atmospheric Pressure Plasma Deposition of Thin Organic Films for Improved Adhesion in Polymer Composites

Download or read book Atmospheric Pressure Plasma Deposition of Thin Organic Films for Improved Adhesion in Polymer Composites written by Dominic Weeber and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Composite polymers in the form of multilayer laminates are used to produce multifunctional surfaces such as food packaging, pool linings, or automotive interiors. Individual sheets provide antimicrobial properties, water resistance, or mechanical properties and require a sound union for robust composite performance. Current industrial processes use toxic isocyanate containing adhesives to bind the multiple layers together, which could be replaced with plasma deposition of nitrogen-rich organic adhesive coatings. Here, atmospheric-pressure dielectric barrier discharge (DBD) plasma is shown to enhance adhesion between a Thermoplastic Polyolefin (TPO) substrate and Polyurethane (PU) coating in an industrially suitable process. Sample production begins by treating TPO with two stages of DBD, operating at 18.7 kHz and 9.9 kVpp. Initial plasma treatment within a simulated air mixture achieves surface activation of TPO through oxidative reactions. A nitrogen-rich organic film is then deposited in the form of a plasma polymer through further DBD treatment using a mixture of nitrogen and either ethylene or butadiene. XPS characterization of samples at this stage showed up to 25 at% Nitrogen incorporated in produced plasma polymers. Following plasma treatment of TPO, solvent based polyurethane is then twice brush coated onto the modified substrate and cured in an oven at 95 °C. Samples are finally assessed for the quality of adhesion between TPO and PU layers by qualitative and quantitative peel testing. Analysis of peel tests has shown clear improvements over samples without plasma polymer deposition, but lower delaminating loads than for samples produced with PECVD. Significant improvements including additional steps for quality control are required at lab scale to meet industrial standards. Nevertheless, the demonstrated adhesion enhancement, using an atmospheric pressure DBD plasma system, is a promising concept for polymer production. " --