Flexible, recyclable, shape memory biomass supramolecular composite films from castor oil and ethyl cellulose

To improve the flexibility, functionality and recyclability of ethyl cellulose (EC)-based film materials, firstly methyl-nadic-anhydride-modified ethyl cellulose (NEC) was synthesized from EC, and then epoxy castor oil (ECO) was prepared from vegetable oils. Next, a series of NEC/ECO supramolecular composite films were prepared via supramolecular recombination and epoxy ring-opening esterification. Then the molecular structure, shape memory, reprocessing, mechanical, thermal properties and other properties were analyzed in detail. The target products NEC and ECO showing excellent compatibility were successfully prepared, and relatively a few microholes existed on the fracture surface of NEC/ECO composite films. The addition of ECO significantly improved the flexibility of the composite films. The supramolecular composite films displayed relatively excellent thermal stability, and initial thermal decomposition temperature all above 300 ℃. Dynamic mechanical thermal analysis showed that the supramolecular structure of the composite systems was completely reconstructed and no obvious glass transition was observed. Under the action of transesterification catalyst, the reversible ester bonds and hydrogen bonds in the composite system endowed the material with superior shape memory property and excellent recyclability. This research can provide experimental basis and theoretical support for the development and application of functional cellulose-based materials.