Molecular Engineering of Elastic and Strong Supertough Polyurethanes

Abstract

Spider silk is an icon of supertough energy absorbing polymeric material which its macromolecular multiblock composition has been attributed to be responsible for such remarkable properties. As in spider silk, polyurethanes can be synthesized with two distinct block which can differ in nature, combining properties like deformability and relatively high strengths. Here we synthesized and studied four different block polyurethanes with two different soft segments (SS) and two different hard segments (HS), with the aim of discovering the best molecular architecture to develop best mechanical performance after macromolecular alignment. The difference between soft segments is the crystalline nature, one in the rubbery state (T g, SS < T room ) and the other in the semicrystalline state at room temperature (T room < T m, SS ). In parallel one hard segment was amorphous in the glassy state (T room < T g, HS ) and the other semicrystalline (T g, HS < T room < T m, HS ). Results indicate that polyurethane with crystalline soft segments produce stronger materials after drawing than polyurethanes with rubbery soft segments, but the most exciting finding is the influence that hard segment has on the mechanical performance of predrawn materials, having polyurethanes prepared with semicrystalline hard segments more capability to undergo macromolecular alignment than materials with glassy segments, developing stiffer, stronger, and tougher materials.

Thermally-responsive biopolyurethanes from a biobased diisocyanate

“…In addition, the increase observed in PI can be attributed to vitrification, which hinders chain extension [31]. In any case, the variations on the molecular weight can be ascribed to segment architecture [32].…”

Relationship between reagents molar ratio and dispersion stability and film properties of waterborne polyurethanes

“…Instead, increasing DMPA content, yield stress and modulus decrease, and elongation at break improves considerably from about 490 to 1197 and 735% in PU2-1 and PU3-1 respectively, probably due to the lower soft segment crystallinity as observed by DSC results. Besides, amorphous soft domains are able to align in the stress applied direction leading to strain induced crystallization [28]. Thus, PU2-1 and PU3-1 samples showed higher stress at break than PU2-1.5 and PU3-1.5, respectively.…”

Silk‐inspired polyurethane containing GlyAlaGlyAla tetrapeptide. II. physical properties and structure

“…28,29 Eceiza et al molecularly engineered elastic and strong supertough polyurethanes to discover the best molecular architecture of the Spider silk to develop best mechanical performance after macromolecular alignment. 30 Consequently, the above helpful investigations prompted us to develop a novel synthetic PU containing polypeptides composed of amino acid residues of silk fibroin. In our previous work, we presented silk-inspired polyurethane biofiber by wet-spinning of biomedical PU/silk proteins blend solution.…”