Wölfel Bastian, Seefried Andreas, Allen Vincent, Kaschta Joachim, Holmes Christopher, Schubert Dirk W
Institute of Polymer Materials, Friedrich-Alexander University, Erlangen-Nürnberg (FAU), Martensstraße 7, 91058 Erlangen, Germany.
Adidas AG, Adi-Dassler-Straße 1, 91074 Herzogenaurach, Germany.
Polymers (Basel). 2020 Aug 25;12(9):1917. doi: 10.3390/polym12091917.
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.
热塑性聚氨酯（TPU）是一种独特的可定制材料，这归因于嵌段共聚物链中硬段和软段之间的相互作用。因此，这种材料可以制造出各种产品。鉴于可持续性方面的循环经济总体趋势，再加上TPU成本相对较高，回收生产以及消费后废弃物的回收利用备受关注。本文提供了一项系统研究，探讨了TPU的性能变化，重点关注两个主要方面。第一个方面着重于通过回收利用来表征基本原材料性能的变化。凝胶渗透色谱法（GPC）和挤出过程中的加工负荷表明，随着回收循环次数的增加，摩尔质量降低，进而粘度降低。这导致在较低摩尔质量下形态发生变化，通过差示扫描量热法（DSC）表征，并通过原子力显微镜（AFM）可视化。随着回收循环次数的增加，摩尔质量和形态的变化对拉伸应力下的材料性能产生影响。第二个方面描述了利用熔喷工艺将回收的TPU加工成无纺布，并对其相关机械性能进行评估，并与分子特性相关联。结果表明，摩尔质量是影响熔喷产品机械性能和加工条件的主导因素。
