A mechanically robust and low heat build-up rubber formed by isoprene rubber assembled with Eucommia ulmoides gum via hydrogen bonding

To combine the high elasticity and good mechanical performance of isoprene rubber (IR) with excellent fatigue resistance and low heat build-up of Eucommia ulmoides gum (EUG), the present study employed a chemical method to graft 4-amino pyridine (AP) onto epoxidized IR and EUG, thereby creating a chemical assembly rubber of amino-pyridine-grafted epoxidized IR (AP-EIR) and amino pyridine-grafted epoxidized EUG (AP-EEUG) via a dynamic hydrogen bonding network.

The presence of hydrogen bonds between AP-EIR and AP-EEUG was confirmed by variable temperature infrared spectroscopy, whereas scanning electron microscopy-energy dispersive spectroscopy revealed a uniform dispersion of zinc oxide and nano-fillers. Hydrogen bonds significantly facilitate strain-induced crystallization between the AP-EIR and AP-EEUG molecules, thereby strengthening their intermolecular interactions. During mechanical deformation, the material primarily dissipates energy through the breaking of hydrogen bonds, which effectively improves the mechanical strength of the material, and the introduction of amino groups in this chemical assembly rubber improves the uniform dispersion of nano-fillers, as well as the interface interaction between rubber and nano-fillers.