Design and Synthesis of Bio-Inspired Polyurethane Films with High Performance

Abstract

In the present work, the synthesis of segmented polyurethanes functionalized with catechol moieties within the hard or the soft segment is presented. For this purpose, a synthetic route of a new catechol diol was designed. The direct insertion of this catechol-free derivative into the rigid phase led to segmented polyurethanes with low performance (σmax ≈ 4.5 MPa). Nevertheless, when the derivative was formally located within the soft segment, the mechanical properties of the corresponding functionalized polyurethane improved considerably (σmax ≈ 16.3 MPa), owing to a significant increase in the degree of polymerization. It is proposed that this difference in reactivity could probably be attributed to a hampering effect of this catecholic ring during the polyaddition reaction. To corroborate this hypothesis, a protection of the aromatic ring was carried out, blocking the hampering effect and avoiding secondary reactions. The polyurethane bearing the protected catechol showed the highest molecular weight and the highest stress at break described to date (σmax ≈ 66.1 MPa) for these kind of catechol-functionalized polyurethanes. Therefore, this new approach allows for the obtention of high-performance polyurethane films and can be applied in different sectors, benefiting from the molecular adhesion introduced by the catechol ring.

A review on microphase separation measurement techniques for polyurethanes

“…Controlling the phase separation can strongly influence PU properties. 6 Molecular weight and polarity of the polyol, [7][8][9] chemistry and structure of the isocyanate and chain extender, [10][11][12][13][14] isocyanate, polyol and chain extender ratios, [15][16][17] utilization of additives in polymerization process, 18 functionalization of the polymer chains [19][20][21][22] and application of shear field and the thermal process [23][24][25] can potentially affect the phase separation and accordingly the PU properties.…”

A Topological Stitching Strategy for Biocompatible Wet Adhesion Using Mussel‐Inspired Polyurethane

“…[ 34,35 ] Taking advantage of the isocyanate groups in polyurethane, functional groups, such as catechol could be efficiently and quantitatively grafted onto designed sites of polymer chain. [ 36–39 ] Furthermore, its high cohesive energy is also conducive to the formation of robust topological entanglement with hydrogels and adherends via hydrogen bond, π–π stacking and other interactions.…”

A Topological Stitching Strategy for Biocompatible Wet Adhesion Using Mussel-Inspired Polyurethane

“…By alternating the "soft" and "hard" segments in the polymer chain, structure, morphology, and mechanical properties of polyurethane could be easily adjusted for desired performances [34,35]. Taking advantage of the isocyanate groups in polyurethane, functional groups such as catechol could be efficiently and quantitatively grafted onto designed sites of polymer chain [36][37][38][39]. Furthermore, its high cohesive energy is also conducive to the formation of robust topological entanglement with hydrogels and adherends via hydrogen bond, π-π stacking and other interactions.…”