FUNCTIONALIZATION OF ETHYLENE-PROPYLENE-DIENE TERPOLYMER VIA THE ALDER ENE REACTION

An ethylene-propylene-diene rubber (EPDM), containing 5 wt% 5-ethylide ne-2-norbornene, was functionalized with maleic anhydride through the Alder Ene reaction at temperatures above 200 degrees C in a co-rotatin g twin screw extruder. Characterization of the maleated product includ ed FT-IR, H-1 and C-13 NMR and GPC. The degree of functionalization wa s determined by infrared analysis and by the mechanical properties of an ionic network formed by neutralizing the maleated rubber with zinc oxide. Increased temperature and maleic anhydride reactant concentrati on were found to improve the extent of reaction. Several Lewis acid sp ecies (SnCl2. 2H(2)O, RuCln. xH(2)O and AlCl3) were tested as catalyst s, and they were found to have a small effect on the degree of functio nalization. This effect improved with reduced acid concentration. Amon g the Lewis acids examined, AlCl3 gave rise to the greatest improvemen t of succinyl anhydride incorporation into the rubber.