Mechanical properties of supramolecular elastomers prepared from polymer-grafted polyrotaxane

- Supramolecular slide-ring (SR) elastomers exhibit smaller Young's moduli than fixed cross-link (FC) elastomers.
- SR elastomers show less strain-hardening and larger strains at break compared with FC elastomers.
- The softness and high deformability of SR elastomers are attributed to the slidability of the cross-links.

Supramolecular slide-ring (SR) elastomers without solvent were fabricated by cross-linking of polymer-grafted polyrotaxane in which α-cyclodextrins (CDs) with poly-ε-caprolactone (PCL) side chains are threaded on a polyethylene glycol (PEG) axial linear chain. The cross-links in the SR elastomers are capable of sliding along the backbone in response to applied stress. Mechanical properties of the SR elastomers with different cross-linking densities were compared with those of fixed cross-link (FC) elastomers prepared from PCL-grafted hydroxypropyl cellulose (HPC) to understand the influence of the slidable cross-links. The SR elastomers are found to undergo less strain-hardening at large strains and demonstrate higher strains at break than the conventional FC elastomers with the same Young's moduli.

163