Bispillar[5]arene-Based\nSlide-Ring Polyrotaxanation\nEnables Enhanced Toughness, Recyclability, Impact, and Puncture Resistance\nof Polyisoprene Elastomers

A series of slide-ring polyrotaxanes (SRPs) have been\nconstructed\nby the solvent-free blending of a ditopic pillar[5]arene (<b>DP5A</b>) and polyisoprene (PIP) after thermal annealing. Solid-state <sup>13</sup>C NMR experiments supported the fact that the pillar[5]arene\nrings of <b>DP5A</b> were threaded by PIP chains to afford physically\ninterlocked networks. Tensile tests revealed that 1% of <b>DP5A</b> can improve the elongation at break from 50 to 239%, the tensile\nmodulus from 2.1 to 3.9 MPa, and the toughness from 0.35 to 4.5 MJ/m<sup>3</sup>. Impact and puncture resistance experiments show that the <b>DP5A</b>-doped materials exhibit remarkable enhancement of protective\nand impalement-resistant performance. The samples can be also recycled\nrepeatedly due to their physical crosslinking nature. The important\nstress delocalization effects have been attributed to the pulley effect\nof <b>DP5A</b> in the SRP materials, which represents a supramolecular\napproach for improving the performance of PIP elastomers.