Structural investigations of polyurethane and silk‐polyurethane composite fiber studied by 13C solid‐state NMR spectroscopy

• Published in: Journal of applied polymer science Vol. 138; no. 40
• Main Authors: Asakura, Tetsuo, Ibe, Yusuke, Jono, Takaki, Matsuda, Hironori, Kuwabara, Nobuo, Naito, Akira
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 20.10.2021; Wiley Subscription Services, Inc
• Subjects: Biocompatibility; biomaterials; Biomedical materials; Coils; Composite materials; Diisocyanates; Elongation; Materials science; Mechanical properties; NMR spectroscopy; Polymer matrix composites; Polymers; polyurethane; Polyurethane resins; proteins; Silk fibroin; spectroscopy; Spectrum analysis; Tensile strength
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.51178

Bombyx mori silk fibroin (SF) fibers possess excellent mechanical properties together with biocompatibility and have attracted great attention in applications including biomaterials. The SF‐polyurethane (PU) composite materials are expected to improve the mechanical properties and expand the application of SF. In this article, PU consisting of isophorone diisocyanate (IPDI) and poly (butylene adipate) is synthesized and characterized using 13C solid‐state NMR spectroscopy. Then, the regenerated SF‐PU (95: 5 wt%) fiber is prepared, which results in a 11.7% increase in tensile strength and 81% increase in elongation‐at‐break compared with those of SF fiber. The reason for the increase is due to the increase of random coil conformation in SF observed by 13C solid‐state NMR and the presence of IPDI in the PU. Thus, it can be emphasized that this PU is very effective in changing the conformation of SF fiber by increasing random coil fraction and improve the mechanical properties.