Carbonate nanophase guided by terminally functionalized polyisoprene leading to a super tough, recyclable and transparent rubber

The interplay between polymer microstructures and vulcanization method has rarely been investigated for rubbers. Herein a terminally hydroxyl functionalized polyisoprene is crosslinked by ring opening of bis(6-membered cyclic carbonate) (bCC), generating uniformly dispersed carbonate nanophase in the polyisoprene matrix. The carbonate phase not only performed as nanofillers to reinforce the rubber and accelerate the strain crystallization behavior of polyisoprene, but also imparted the recovery property and recyclability into the rubber. In contrast, the copolymer without the terminal block showed disorderly carbonate nanophase and much inferior properties. The mechanical strength and toughness could be finely tuned by the content of bCC crosslinkers, which are even superior to those of vulcanized natural rubber. In addition, the crosslinked polyisoprene exhibits notable transparency, which is not common to vulcanized rubber and could meet the requirements for transparency of rubber products in some fields.