Rosin-citraconic anhydride adducts as modifiers of elastomeric compositions

By reacting of rosin resin acids with citraconic anhydride at 140–180 °C for 2–4 hours, rosin-citraconic anhydride adducts with varying contents of citraconopimaric acid (from 30 to 55 %) were synthesized. When treating rosin-citraconic anhydride adducts with primary aliphatic amines (octyl-, octadecylamine) and aniline, the corresponding nitrogen-containing derivatives were obtained. The thermal stability of rosin-citraconic anhydride adducts and their modifying effect on the properties of unfilled elastomer compositions and filled industrial rubber mixtures and their vulcanizates were studied. It has been established that the most effective modifier is a rosin-citraconic anhydride adduct containing 55 % citraconopimaric acid octylimide (ORCA) with increased thermal stability (265 °C). This additive reduces Mooney viscosity by up to 30 % and increases the vulcanization rate of production tire rubber compounds by 40 %, which reduces the energy intensity of technological processes. The ORCA modifier improves the properties of rubber: it increases the resistance of rubber to high temperatures (90 °C) in a steam-air environment with an increase in the strength of the bond between rubber and textile cord by 43.8 %; reduces the mechanical loss tangent to 0.235, which makes it possible to reduce heat generation under dynamic influences on the product; increases abrasion resistance by 14 % and resistance to thermal aging by 10 %.