Supramolecular hierarchical polyurethane elastomers for thermal and mechanical property optimization. (8th November 2022)

• Record Type: Journal Article
• Authors: Lu, Ru-Qiang; Concellón, Alberto; Wang, Pan; Swager, Timothy M.; Hsieh, Alex J.
• Is Part Of: Polymer. Volume 260(2022)
• Publication Date: 2022-11-08
• Subjects: Hierarchical polyurethane elastomers -- Supramolecular hydrogen bond interactions -- Intersegmental mixing -- Dynamic glass transition temperatures -- Mechanical properties; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2022.125363
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Supramolecular chemical designs that integrate complementary hydrogen bond donor and acceptor complexes in hierarchical polyurethane elastomers are reported. N 2, N 6 -bis(2-hydroxyethyl)pyridine-2, 6-dicarboxamide (PDA) and 5, 5-bis(3-hydroxypropyl)barbituric acid (BBA) react with 4, 4′-methylenediphenyl diisocyanate (MDI) to produce hard segments capable of multiple intermolecular hydrogen bonds in MDI-PDA/BBA-poly(tetramethylene oxide) (PTMO) polyurethanes. The addition of PDA facilitates the formation of a supramolecular complex, and BBA affords greater intersegmental mixing. As a result, these polyurethanes exhibit higher glass transition temperatures ( T g ) and greater strain hardening/strengthening under tensile deformation than a microphase-separated MDI-butanediol (BDO)-PTMO analog. Additionally, increased PDA and BBA contents results in up to a 60 °C increase of T g determined at 1 Hz via DMA relative to those determined by calorimetric measurements via DSC, which is considerably higher than the 15 °C T g increase observed in the MDI-BDO-PTMO analog. These results highlight a significant interplay between intersegmental mixing and supramolecular hydrogen bond interactions for the design of robust hierarchical elastomers. Graphical abstract: Image 1 Highlights: Supramolecular designs of robust PDA/BBA polyurethanes with multi-functionality. Synergy between segmental mixing and supramolecular hydrogen bond interactions. High cohesive energy densities result in high T g s, high strength and toughness.