Gaël Colomines

Biofriendly ionic liquids for starch plasticization: a screening approach

A series of cholinium cation-based bioionic liquids (BioILs) were synthetized with the aim of screening their performance as potential plasticizers of thermoplastic starch. To synthesize these BioILs, two easy and fast synthetic routes were selected: an ion exchange reaction, direct and economical, and a two-step acid–base reaction. Most of these BioILs allowed efficient plasticization of starch by film casting. The structure of the anion used significantly influences the thermo(hygro)mechanical and recrystallization behavior, making it possible to modulate the properties of the final material.

Choline chloride vs choline ionic liquids for starch thermoplasticization

Native starch containing 12% water was melt processed in presence of 23% of various plasticizers at 120°C, either by simple compression molding or by extrusion using a laboratory scale microcompounder. Glycerol, a typical starch plasticizer, was used as a reference and compared to three choline salts: raw choline chloride (which is a solid in dry state with a melting point above 300°C), and two ionic liquids synthesized from this precursor (choline acetate and choline lactate, liquids below 100°C). These ionic plasticizers were shown to allow a more efficient melting of native starch in both processes. The investigation of macromolecular structure changes during processing shows that this efficiency can be ascribed to a starch chain scission mechanism, resulting in lower specific mechanical energy input need for starch thermoplasticization compared to glycerol plasticized starch. Compared to the synthesized ionic liquids, raw commercial choline chloride leads to a good compromise between limited chain scission, and final water uptake and thermomechanical properties.

Thermo-Kinetic Analysis of Liquid Silicone Rubber

Modeling and optimization of LSR parts require an accurate kinetic modeling of the material crosslinking. Calorimetric and mechanical measurements for different temperature ramps are used in order to calculate the crosslinking extent as a function of time and temperature. These measurements are numerically treated in order to determine the parameters of a representative model. The chosen model will be used to simulate a LSR molded parts and design a LSR controlled molding setup.