Rupture, orientation and strain-induced crystallization of polymer chain and network in vulcanized polyisoprene during uniaxial deformation by in-situ Electron Spin Resonance (ESR) and synchrotron X-ray analysis

Different network structures of vulcanized polyisoprene rubbers were studied by in-situ ESR and synchrotron X-ray during deformation to analyze the rupture, orientation, and strain-induced crystallization of polymer chains and network points. Rupture of network points occur, depending on network structure, and create an un-reversible change in vulcanized rubber. The flexibility of network points affects the possibility of rupture, polymer orientation and strain-induced crystallization. Peroxide vulcanized network is rigid and un-rupturable. Poly-sulfide rich vulcanized network is more flexible and less rupturable than mono-sulfide rich vulcanized network. Chain flexibility and rupturability of network points affect the strain-induced crystallization and stress-strain relation.