Soft segment‐free functional polyurethane: A versatile candidate for heat‐healability, non‐dissociative mechanism, and high elongation adhesive materials

• Published in: Polymers for advanced technologies 2021-09, Vol.32 (9), p.3523-3534
• Main Authors: Edachery Veetil, Rashmi, Vijayalakshmi, Kunduchi Periya, Srinivas, Chinthalapalli, Mathew, Dona, Kalamblayil Sankaranarayanan, Santhosh Kumar
• Format: Article
• Language: English
• Subjects: Elongated structure; FTIR; Functional groups; functional PU; high elongation adhesives; Hydroxyl groups; H‐bonding; Morphology; Polyurethane resins; Segments
• ISSN: 1042-7147; 1099-1581
• DOI: 10.1002/pat.5363

Functional and re‐processable polyurethane (soft‐segment free, FPU) is synthesized and later it is converted into substituted PUs by reaction with suitable molecules to enrich/block H‐bonding features inherent with FPU. By these substitutions, H‐bonding is easily altered as observed in FTIR investigations. Spherical morphology of FPU turned into elongated/twisted one due to the separation of polymer chains by these molecules (bulky or long chain groups). Owing to the presence of hydroxyl groups, the dissociation of FPU on re‐processing at 150°C was dodged and achieved heat‐healable PUs. Interestingly, a trivial quantity (2.5 wt%) of FPU in an epoxy‐amine cross‐linked structure increased the elongation to nearly fourfold (5%‐21%). The soft‐segment free nature of PU and its functional groups have key role in facilitating easy incorporation of PU into epoxy matrices to provide exotic properties.