Petroleum-based polymer
materials heavily rely on nonrenewable
petrochemical resources, and damping materials are an important category
of them. As far as green chemistry, recycling, and damping materials
are concerned, there is an urgent need for renewable and recyclable
biobased materials with high damping performance. Thus, this study
designs and synthesizes a series of polylactic acid-based thermoplastic
polyurethanes (PLA-based TPUs) composed of modified polylactic acid
polyols, 4,4′-diphenylmethane diisocyanate, and 1,4-butanediol.
PLA-based TPUs, as prepared, display excellent mechanical properties,
damping performance, and biocompatibility. Otherwise, they can be
used for three-dimensional printing (3D printing). Under multiple
recycling, the overall performance of PLA-based TPUs is still maintained
well. Overall, PLA-based TPUs, as designed in this article, show a
potential application in damping materials under room temperature
and personalized shoes via 3D printing and could realize resource
recycling and material reuse.
The operation of mechanical equipment inevitably generates vibrations and noise, which are harmful to not only the human body but also to the equipment in use. Damping materials, which can convert mechanical energy into thermal energy, possess excellent damping properties in the glass transition region and can alleviate the problems caused by vibration and noise. However, these materials mainly rely on petroleum-based resources, and their glass transition temperatures (Tg) are lower than room temperature. Therefore, bio-based materials with high damping properties at room temperature must be designed for sustainable development. Herein, we demonstrate the fabrication of bio-based millable polyurethane (BMPU)/hindered phenol composites that could overcome the challenges of sustainable development and exhibit high damping properties at room temperature. BMPUs with a high Tg were prepared from modified poly (lactic acid)-based polyols, the unsaturated chain extender trimethylolpropane diallylether, and 4,4′-diphenylmethane diisocyanate, and 3,9-Bis-{1,1-dimethyl-2[β-(3-tert-butyl-4-hydroxy-5-methylphenyl-)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro [5,5]-undecane (AO-80) was added to prepare BMPU/AO-80 composites. Finally, the properties of the BMPUs and BMPU/AO-80 composites were systematically evaluated. After adding 30 phr of AO-80, the Tg and maximum loss factor (tan δmax) of BMPU/AO-80 composites increased from 7.8 °C to 13.5 °C and from 1.4 to 2.0, respectively. The tan δmax showed an improvement of 43%. Compared with other polyurethanes, the prepared BMPU/AO-80 composites exhibited higher damping properties at room temperature. This study proposes a new strategy to reduce society’s current dependence on fossil resources and design materials featuring high damping properties from sustainable raw materials.
Rubber composites make an important contribution to eliminating vibration and noise owing to their unique viscoelasticity. However, it is important to find alternative bio-based products with high damping properties owing to the shortage of petrochemical resources and poor performance. The ability to self-heal is an additional characteristic that is highly desirable because it can further increase the service life and safety of such products. In this study, a bio-based polylactic acid thermoplastic polyurethane (PLA-TPU) and its composites (PLA-TPU/AO-80) are synthesized. The reversible sacrificial hydrogen bonds in the composites increase the peak value of the loss factor (tan 𝜹 max ) from 0.87 to 2.12 with a high energy dissipation efficiency of 99% at 50% strain. After being heated for 15 min, the healed sample recovers 81.98% of its comprehensive mechanical properties due to the reorganization of the hydrogen bonds. Its tensile strength remains at 93.4% after recycling five times. Moreover, its shape memory properties show a response temperature close to the human body temperature making it an ideal candidate for medical applications.
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