In this review, the application of deep eutectic solvents (DESs) as starch solvents, plasticizers and for other treatment has been described. Starch, as one of the most abundant biopolymers, is considered for forming new biodegradable materials. This new approach, referring to applying deep eutectic solvents for dissolving starch, its plasticization and other modifications, was presented. A DES could be a good alternative for common starch plasticizers (e.g., glycerol, urea) as well as recently considered ionic liquids. The high variety of DES component combinations makes it possible to obtain materials with the properties specific for given applications.

In the paper, the method of obtaining the potato starch nanocomposites plasticized with a deep eutectic solvent is described. The deep eutectic solvent based on choline chloride and malic acid (CM, molar ratio 1:1) was used as the plasticizer. The effect of the sodium and calcium montmorillonite (MMTNa, MMTCa respectively) addition on the properties of potato starch films was investigated. The thermal, mechanical, and barrier properties were determined. Moreover, a moisture absorption test was performed. The starch gelatinization temperature increased in the presence of montmorillonite. The values of glass transition determined by DMTA depended on the nanofiller type. For the systems containing MMTCa, they generally decreased with its content (although still lower than reference samples). The obtained nanocomposites showed improved mechanical and barrier properties. The highest values of tensile strength and Young’s modulus were noted for the system containing 1% MMTNa. The XRD revealed that only the films with MMTNa exhibited intercalation. The homogeneity of the samples decreased with increasing nanofiller concentration. This was probably due to the occurrence of choline chloride-montmorillonite interactions, which were more favored than clay-starch interactions.

A natural deep eutectic solvent (NADES) based on choline chloride and malic acid was used to plasticize potato starch. The influence of starch gelatinization temperature, NADAES content and the method of its incorporation (before and after gelatinization) on starch plasticization was investigated. Polymer-plasticizer interactions were studied using MDSC, DMTA, XRD and FTIR-ATR methods. The viscosity of starch solutions as well as the mechanical properties and water absorption of the obtained films were determined. Gelatinization conditions had a significant impact on the viscosity of starch solutions and the physicochemical properties of the obtained films. The cross-linking reaction between starch and malic acid was confirmed by MDSC, DMTA, and mechanical properties. Slight recrystallization of starch was observed after 12 months of storage.

For wider use of starch in the production of biodegradable plastics, it is necessary to search for new effective plasticizers. In this study, the effect of seven deep eutectic solvents (DES) based on choline chloride and carboxylic acid (levulinic, lactic, malonic, itaconic, malic, tartaric and...

For the first time, choline dihydrogencitrate salt (CCT) was tested as a sole plasticizer for starch-based materials. The effect of CCT content on the physicochemical properties of the obtained films was evaluated. The FTIR and XRD measurements revealed that CCT exhibited the ability to disrupt the crystalline regions of potato starch. Also, DMTA and the mechanical test results showed that CCT acted as a primary plasticizer, leading to increased flexibility of starch-based films. Considering the transparency and mechanical properties, the efficient content of CCT was 25 wt.%. The obtained materials exhibited lower moisture absorption levels when compared to other common starch plasticizers, which makes them interesting as less moisture-sensitive films for packaging.