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    Novel Biobased Self-Healing Ionomers Derived from Itaconic Acid Derivates
    (Weinheim : Wiley-VCH, 2021) Meurer, Josefine; Hniopek, Julian; Dahlke, Jan; Schmitt, Michael; Popp, Jürgen; Zechel, Stefan; Hager, Martin D.
    This article presents novel biobased ionomers featuring self-healing abilities. These smart materials are synthesized from itaconic acid derivates. Large quantities of itaconic acid can be produced from diverse biomass like corn, rice, and others. This study presents a comprehensive investigation of their thermal and mechanical properties via differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), and FT-Raman and FT-IR measurements as well as dynamic mechanic analysis. Within all these measurements, different kinds of structure-property relationships could be derived from these measurements. For example, the proportion of ionic groups enormously influences the self-healing efficiency. The investigation of the self-healing abilities reveals healing efficiencies up to 99% in 2 h at 90 °C for the itaconic acid based ionomer with the lowest ionic content. © 2020 The Authors. Macromolecular Rapid Communications published by Wiley-VCH GmbH
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    Tailor-Made Functional Polymethacrylates with Dual Characteristics of Self-Healing and Shape-Memory Based on Dynamic Covalent Chemistry
    (New York, NY [u.a.] : Wiley InterScience, 2020) Mondal, Prantik; Behera, Prasanta K.; Voit, Brigitte; Böhme, Frank; Singha, Nikhil K.
    New shape memory polymers with self-healing behavior are obtained by thermoreversible Diels–Alder (DA) cross-linking of a furfuryl group-containing star-block copolymer with 1,1'-(methylenedi-4,1-phenylene)bismaleimide. The star-block copolymer consisting of a 3-arm polycaprolactone (PCL) core and a polyfurfuryl methacrylate shell is synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. For this, a 3-arm macro-RAFT agent based on PCL is converted with an appropriate amount of furfuryl methacrylate in the presence of a radical initiator. Films of the DA network are partly insoluble at ambient temperatures. After annealing at 120 °C the films become completely soluble because of the progressing retro-DA reaction. Evaporation of the solvent and subsequent annealing at 60 °C restores the original insoluble state of the material. By means of a scratch test and tensile tests on cut and subsequently mended samples it is shown that the retro-DA reaction facilitates self-healing. Additionally, the films show pronounced shape memory effects with reasonable shape recovery and fixity ratios, which are attributed to the melting and crystallization of the PCL phase. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim