KES1-1571
Dynamic crosslinking of polymers for combining environmental friendliness and high performance
Topic
S1. Polymer Synthesis
When and Where
Sep 30, 2026
11:10 - 11:35
Room 101
Session Chairs
In-Hwan LEE
Presenter(s)
Naoko Yoshie (The University of Tokyo)
Co-Author(s)
Abstract
Crosslinking is one of the most effective strategies for improving the mechanical properties of polymers. Permanent crosslinks, however, often compromise recyclability. Dynamic crosslinking based on hydrogen bonds (H-bonds) provides mechanical reinforcement while enabling network rearrangement, self-recovery, and recycling. Rigid multiple H-bonding motifs, such as DNA nucleobases, have been widely employed because they efficiently form supramolecular polymer networks. However, their strong and directional interactions often suppress the dynamic behavior required for functions such as self-recoverability. In contrast, we have explored structurally flexible multiple H-bonding motifs.
This concept emerged from our studies on polybutadiene bearing aliphatic vicinal diol (VD) groups. Owing to rotational freedom around the C–C bond, VDs form multiple stable H-bonded dimer structures. We propose that frequent interconversion among these structures prolongs intermolecular association, whereas multiple accessible dimer structures facilitate reassociation after dissociation. To clarify the role of structural flexibility, we compared norbornene-based copolymers bearing either flexible vicinal dimethanol (diol) or rigid g-lactam (amide) groups. Although the two motifs possess comparable H-bonding energies, a higher diol content was required to match the Young's modulus of the amide-containing polymer. At comparable Young's moduli, the diol-containing polymer exhibited greater stress at large strains and superior self-recoverability, demonstrating that structural flexibility enhances dynamic performance independently of H-bond strength.
These studies establish structural flexibility as a new molecular design parameter for robust yet dynamic polymeric materials. This presentation will highlight how flexible H-bonding motifs provide a promising strategy for designing robust, recyclable, and environmentally friendly polymeric materials.
This concept emerged from our studies on polybutadiene bearing aliphatic vicinal diol (VD) groups. Owing to rotational freedom around the C–C bond, VDs form multiple stable H-bonded dimer structures. We propose that frequent interconversion among these structures prolongs intermolecular association, whereas multiple accessible dimer structures facilitate reassociation after dissociation. To clarify the role of structural flexibility, we compared norbornene-based copolymers bearing either flexible vicinal dimethanol (diol) or rigid g-lactam (amide) groups. Although the two motifs possess comparable H-bonding energies, a higher diol content was required to match the Young's modulus of the amide-containing polymer. At comparable Young's moduli, the diol-containing polymer exhibited greater stress at large strains and superior self-recoverability, demonstrating that structural flexibility enhances dynamic performance independently of H-bond strength.
These studies establish structural flexibility as a new molecular design parameter for robust yet dynamic polymeric materials. This presentation will highlight how flexible H-bonding motifs provide a promising strategy for designing robust, recyclable, and environmentally friendly polymeric materials.
