Characterization of Thermoplastic Polyurethane (TPU) and Ag Carbon Black TPU Nanocomposite for Potential Application in Additive Manufacturing (Postprint)
University of Dayton Research Institute Dayton United States
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Electromechanical, adhesion, and viscoelastic properties of polymers and polymer nanocomposites PNCs are of interest for additive manufacturing AM and flexible electronics. Developmentoptimization of inks for AM is complex, expensive, and substrateinterface dependent. This study investigates properties of free standing films of a thermoplastic polyurethane TPU polymer and an Ag-carbon black Ag-CB TPU PNC in a lightly loaded low strain compression contact as a rough measure of their suitability for AM. The TPU exhibited high hysteresis and a large viscoelastic response, and sufficient dwell time was needed for polymer chain relaxation and measurable adhesion. A new discovery is that large enough contact area is needed to allow longer time constant polymer ordering in the contact that led to higher adhesion and better performancereliability. This has previously unknown implications for interface size relative to polymer chain length in AM design. The standard linear model was found to be a good fit for the viscoelastic behavior of the TPU.