Design of crystallisation-inhibited polymer networks for absorption and storage of high mechanical impacts
Final Report Abstract
We have shown that a cold-programmable SMP is suitable as shock- and energy absorber for effective cushioning of impact force, vibration, and chatter as it is needed when such a material is used, for example, as safety line for catching a free-falling deadweight. While coldprogrammable SMNR failed under the used test conditions, critically cross-linked x-sPP shows excellent shock- and energy-absorption capability. A deadweight of 0.7 kg dropped from a height of 80 mm causes for x-sPP a maximum impact force of 12.8 N, which is only 38% and 54% of that caused by Dyneema and rubber, respectively. A kinetic energy absorption of x-sPP of 91% within the first impact in contrast to Dyneema and rubber with 48% and 19%, respectively, results in an extremely short oscillation time of about 2 s until the deadweight comes to rest. Although the maximum jerk for x-sPP is slightly higher than that of the rubber reference for a deadweight of 0.7 kg and a drop height of 80 mm, this important quantity stays nearly constant or is even getting smaller for x-sPP with increasing mass of the deadweight or drop height. Thus, x-sPP avoids harmful jerks better the more it is loaded. Further, x-sPP can be reused for at least 10 times, since it restores its original dimensions after being heated above the melting temperature of the strain-stabilizing crystals and, subsequently cooled to room temperature. Altogether, x-sPP merges the impact force cushioning of an elastomer with the kinetic energy dissipation of a plastically deformable material and, thus, is principally well suited for applications such as, safety lines for climbers or bungee ropes after the problem of thermal crystallisation has been overcome.
Publications
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Heating Rate Sensitive Multi-Shape Memory Polypropylene: A Predictive Material. ACS Applied Materials & Interfaces, 8, 13684-13687 (2016)
R. Hoeher, T. Raidt, F. Katzenberg, J. C. Tiller
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Ionically Cross-Linked Shape Memory Polypropylene. Macromolecules, 49 (18), 6918-6927 (2016)
T. Raidt, R. Hoeher, M. Meuris, F. Katzenberg, J. C. Tiller
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Multiaxial Reinforcement of Cross-Linked Isotactic Polypropylene upon Uniaxial Stretching. Macromolecular Materials and Engineering 302, 1600308 (2017)
T. Raidt, R. Hoeher, F. Katzenberg, J. C. Tiller
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Cross-Linking of Semi-Aromatic Polyesters Towards High Temperature Shape Memory Polymers with Full Recovery. Macromolecular Rapid Communications 39 (6), 1700768 (2018)
T. Raidt, M. Schmidt, J.C. Tiller, F. Katzenberg
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Shock-and Energy Absorption Capability of Cold-Programmable Shape Memory Polymers. Macromolecular Chemistry and Physics 1800274 (2018)
T. Raidt, P. Santhirasegaran, R. Hoeher, J.C. Tiller, F. Katzenberg
