The two modified rubbers that have been used were: a maleic anhydride
(MA) modified ethylene-propylene (75/25 wt%) diene terpolymer (0.5 wt% MA), type Royaltuf 465A
and a maleic anhydride (MA) modified ethylene-propylene (50/50 wt%) diene terpolymer (1 wt% MA),
type Royaltuf 465. These rubbers were kindly supplied by Uniroyal