Recyclable Diels–Alder Furan/Maleimide Polymer Networks with Shape Memory Effect

A series of recyclable networks with shape memory effect was prepared by the Diels–Alder reaction between furan-functionalized poly­(hydroxyaminoethers) (PHAEs) and 1,5-bis­(maleimido)-2-methylpentane (MPDBMI). Compression molding was used to recycle the MPDBMI/PHAE films. The Diels–Alder and retro-Diels–Alder reactions between PHAEs and MPDBMI were confirmed by Fourier transform infrared, differential scanning calorimetry (DSC), and solubility test. Furthermore, the mechanical properties and shape memory properties of the original and recycled MPDBMI/PHAE networks were systematically investigated by a tensile test and a quantitative shape memory evaluation method, respectively. DSC measurement indicated that the retro-Diels–Alder reaction will occur upon heating, and the solubility test showed that the recycled MPDBMI/PHAE films may still be considered as recyclable. Moreover, the tensile test at room temperature disclosed that both the original and recycled MPDBMI/PHAE networks exhibited tough properties: all specimens exhibited either the ductile plastic fracture feature with the appearance of yielding phenomenon or the rubber property with large elongation at break. Quantitative shape memory evaluation revealed excellent shape memory performance of the original and recycled MPDBMI/PHAE networks