Binary Modification of Eucommia ulmoides Gum Toward Elastomer with Tunable Mechanical Properties and Good Compatibility

Eucommia ulmoides gum (EUG) was applied in blend rubber with a heavily limited amount because of its duality of rubber and plastic, and an efficient way of triazolinedione (TAD)-based Alder-ene reaction was used to improve the elastic properties of EUG. Binary modification of EUG with two TADs containing hexyl and polyhedral oligomeric silsesquioxane (POSS) groups were conducted to generate the modified EUG elastomers with tunable mechanical properties and good compatibility by varying TAD contents. When the low hexyl (1%) and POSS (0.2%) TADs incorporated, the modified EUGs displayed high tensile strength of 36.57 MPa with the elongation at break of 876%, and thus high toughness of 152.14 MJ m ⁻³ . If high contents of hexyl (20%) and POSS (0.2%) TADs employed, the modified EUGs exhibited excellent elongation at break of 1165% and recovery rate of 60%, and especially its loss factor reached up to 0.83‑0.65 at 20‑70°C. Therefore, the modified EUGs containing the polar urazole and POSS groups should be a novel elastomer with good compatibility, wear resistance, and damping properties.