Preparation and Properties of Vegetable-Oil-Based Thioether Polyol and Ethyl Cellulose Supramolecular Composite Films

Ethyl cellulose (EC), an important biomass-based material, has excellent film-forming properties. Nevertheless, the high interchain hydrogen bond interaction leads to a high glass transition temperature of EC, which makes it too brit-tle to be used widely. The hydroxyl group on EC can form a supramolecular system in the form of a non-covalent bond with an effective plasticizer. In this study, an important vegetable-oil-based derivative named dimer fatty acid was used to prepare a novel special plasticizer for EC. Dimer-fatty-acid-based thioether polyol (DATP) was synthe-sized and used to modify ethyl cellulose films. The supramolecular composite films of DATP and ethyl cellulose were designed using the newly-formed van der Waals force. The thermal stability, morphology, hydrophilicity, and mechanical properties of the composite films were all tested. Pure EC is fragile, and the addition of DATP makes the ethyl cellulose films more flexible. The elongation at the break of EC supramolecular films increased and the tensile strength decreased with the increasing DATP content. The elongation at the break of EC/DATP (60/40) and EC/DATP (50/50) was up to 40.3% and 43.4%, respectively. Noticeably, the thermal initial degradation temperature of the film with 10% DATP is higher than that of pure EC, which may be attributed to the formation of a better supramolecular system in this composite film. The application of bio-based material (EC) is environmentally friendly, and the novel DATP can be used as a special and effective plasticizer to prepare flexible EC films, making it more widely used in energy, chemical industry, materials, agriculture, medicine, and other fields.