Mechanically robust and thermal stable polyurethane elastomers with self‐healing and recycling ability

• Published in: Polymer engineering and science Vol. 65; no. 3; pp. 1136 - 1150
• Main Authors: Pan, Tian, Yuan, Li, Liang, Guozheng, Gu, Aijuan
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.03.2025; Society of Plastics Engineers, Inc; Blackwell Publishing Ltd
• Subjects: Amines; Chemical synthesis; Crosslinking; Dimethylformamide; Elastomers; Elongation; Glass transition temperature; Healing; Heat treatment; Hexamethylene diisocyanate; Hydrogen; hydrogen bonds; Isocyanates; Mechanical properties; mechanical property; Polyols; Polytetrahydrofuran; polyurethane elastomer; Polyurethane resins; Polyurethanes; Recycling; Shape memory; Stress relaxation; Tensile strength; thermal property; Toughness
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.27062

A series of supramolecular interaction‐based polyurethane elastomers (SPUEs) were synthesized from the reactions of hexamethylene diisocyanate‐functionalized 2‐ureido‐4[1H]‐pyrimidinone (UPy) derivatives and polytetrahydrofuran (PTHF), followed by reactions with polyether amines. The tensile strength, elongation at break and toughness of the optimum SPUE system can reach 62 MPa, 693%, and 189 MJ·m−3, respectively. All SPUEs have much higher tensile strength and toughness than the reference materials while maintaining large elongation at break owing to the increased hydrogen (H)‐bonding sites and favorable crosslinked networks. SPUEs possess double glass transition temperatures and display good multi‐shape memory behaviors resulting from different soft and hard domains. SPUEs have nanophase‐separated structures, which endow them with excellent transparency within visible light wavelengths ranging from 500 to 800 nm. Owing to adequate H‐bonds, SPUEs exhibit stress relaxation, shape‐reconfigurability, and outstanding healing/recycling properties. The damaged SPUEs show high healing efficiency of 77–97% after heat treatment at 100°C for 12 h. The used SPUEs can be recycled multiple times by dissolving them in N, N‐dimethylformamide (DMF) at ~110°C for 20–30 min, and the third recycled SPUEs can have high mechanical strength retention rate of up to 100%. Highlights Elastomer was constructed through H‐bonds and favorable crosslinked networks. The elastomer has high comprehensive mechanical properties. The elastomer has extremely low and high glass transition temperatures. The elastomer has a high self‐healing efficiency of ~97% after treatment at 100°C. The elastomer can be recycled multiple times. UPy‐contained polyurethane elastomers with favorable crosslinked networks have excellent comprehensive mechanical properties, extremely low and high glass transition temperatures, excellent healing and recyclable properties.