Ionomer‐based polyurethanes: a comparative study of properties and applications

Abstract

International audiencePolyurethanes cover a large range of materials exhibiting various physical and mechanical properties making them useful in different applications such as elastomers or biomaterials, for instance. The introduction of ionic groups in the polyurethane backbone opens the way to new applications where the ionic groups can act as physical crosslinkers that greatly modify the final mechanical and thermal properties of the materials. Furthermore, the hydrophilicity of the chains can be enhanced by the presence of the ionic species, and so the materials can be processed as conventional dispersions even in a polar solvent such as water. As a consequence the applications are numerous; the main commercial outlets are focused on coatings and textiles industries where they can be used as waterproof coatings or substitutes for leather. But these materials can also be used in high-tech industries for shape memory materials, biomedical devices and biocompatible materials. This review summarizes the latest developments of this class of promising materials and provides the reader with the potentialities of these polymers in various areas

Monitoring of polyurethane dispersions after the synthesis

“…Nevertheless, the chemical changes can be monitored with FT-IR. [4][5][6][7][8][9][10][11][12][13][14]21,26,27 Table 3 consists of the formulation and properties of the PU prepolymer before being dispersed. There is no doubt that PUD colloidal features depend upon the PU prepolymer.…”

“…The molecular mass is increasing during the ageing, as can be expected due to the formation of urea linkages, which are formed after the reaction between NCO and water. 3,5,6,8,[11][12][13][14][15][16][17] The M w /M n ratio also increases from the initial 1.77 to 2.99 at the end. Nevertheless, the molecular mass distribution remains relatively narrow, indicating that the chain extension is relatively uniform.…”

“…In the final stage, a water-soluble diamine is added as the chain extender to increase the molecular mass. 3,[5][6][7][8][11][12][13][14][15] During all the stages of the synthesis numerous side reactions can occur due to the NCO reactivity. 5,12,16 Due to the system complexity, where many principles are in place but only a few have an important influence on the final macroscopic material properties, this field of research is rather more of an industrial importance.…”

“…The required high molecular mass is achieved with a chain extension with multifunctional amines. [3][4][5][6][7] Many processes are used for a PUD preparation, although prepolymer mixing and acetone processes dominate in industrial applications. A prepolymer mixing process is mostly employed for the preparation of PUDs as coating binders.…”

Polyurethane/poly(ethylene‐co‐ethyl acrylate) and functional carbon black‐based hybrids: Physical properties and shape memory behavior

“…This shape-memory effect is usually induced by thermal stimulation, electric field, chemicals, and pH. [7][8][9] Polymer blending is also a technique used for the improvement of polymer properties. In this regard polyacrylate blends with functional characteristics have been reported.…”