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Article

Recycling and Reprocessing of Thermoplastic Polyurethane Materials towards Nonwoven Processing

1
Institute of Polymer Materials, Friedrich-Alexander University, Erlangen-Nürnberg (FAU), Martensstraße 7, 91058 Erlangen, Germany
2
Adidas AG, Adi-Dassler-Straße 1, 91074 Herzogenaurach, Germany
*
Authors to whom correspondence should be addressed.
Polymers 2020, 12(9), 1917; https://doi.org/10.3390/polym12091917
Received: 28 June 2020 / Revised: 15 August 2020 / Accepted: 21 August 2020 / Published: 25 August 2020
Thermoplastic Polyurethane (TPU) is a unique tailorable material due to the interactions of hard and soft segments within the block-copolymer chain. Therefore, various products can be created out of this material. A general trend towards a circular economy with regards to sustainability in combination with TPU being comparably expensive is of high interest to recycle production as well as post-consumer wastes. A systematic study investigating the property changes of TPU is provided, focusing on two major aspects. The first aspect focuses on characterizing the change of basic raw material properties through recycling. Gel permeation chromatography (GPC) and processing load during extrusion indicate a decrease in molar mass and consequently viscosity with an increasing number of recycling cycles. This leads to a change in morphology at lower molar mass, characterized by differential scanning calorimetry (DSC) and visualized by atomic force microscope (AFM). The change in molar mass and morphology with increasing number of recycling cycles has an impact on the material performance under tensile stress. The second aspect describes processing of the recycled TPU to nonwoven fabrics utilizing melt blowing, which are evaluated with respect to relevant mechanical properties and related to molecular characteristics. The molar mass turns out to be the governing factor regarding mechanical performance and processing conditions for melt blown products. View Full-Text
Keywords: recycling; reprocessing; TPU; thermoplastic elastomers; TPE; thermoplastic; polyurethane; elastomers; nonwoven; processing; melt blown; molar mass; mechanical properties; methylendiphenylisocyanate; MDI; polytetramethylene glycol; PTMG; morphology; structure; phase separation; sustainability; circular economy recycling; reprocessing; TPU; thermoplastic elastomers; TPE; thermoplastic; polyurethane; elastomers; nonwoven; processing; melt blown; molar mass; mechanical properties; methylendiphenylisocyanate; MDI; polytetramethylene glycol; PTMG; morphology; structure; phase separation; sustainability; circular economy
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MDPI and ACS Style

Wölfel, B.; Seefried, A.; Allen, V.; Kaschta, J.; Holmes, C.; Schubert, D.W. Recycling and Reprocessing of Thermoplastic Polyurethane Materials towards Nonwoven Processing. Polymers 2020, 12, 1917. https://doi.org/10.3390/polym12091917

AMA Style

Wölfel B, Seefried A, Allen V, Kaschta J, Holmes C, Schubert DW. Recycling and Reprocessing of Thermoplastic Polyurethane Materials towards Nonwoven Processing. Polymers. 2020; 12(9):1917. https://doi.org/10.3390/polym12091917

Chicago/Turabian Style

Wölfel, Bastian, Andreas Seefried, Vincent Allen, Joachim Kaschta, Christopher Holmes, and Dirk W. Schubert 2020. "Recycling and Reprocessing of Thermoplastic Polyurethane Materials towards Nonwoven Processing" Polymers 12, no. 9: 1917. https://doi.org/10.3390/polym12091917

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