Grafting functional species to rubber

A method for producing a functionalized rubber, the method comprising:

• adding a diene rubber selected from natural rubber, a synthetic polyisoprene rubber or combinations thereof and an organic peroxide to a mixer, the organic peroxide represented by the formula R1—O—O—R2, wherein R1 is selected from hydrogen or an organic moiety of between 4 and 15 carbon atoms and R2 comprises a functional moiety selected from an amino, an amide, a hydroxyl, a sulfide, an epoxy, a tin-containing, an alkoxysilyl, a silanol, a carbonyl, a carboxyl, a thiocarbonyl, an ammonium, a nitrile, an imine functional moiety or combinations thereof;
• mixing a mix composition comprising the diene rubber and the organic peroxide until the mix composition reaches a target temperature of between 120° C. and 190° C.;
• decomposing the organic peroxide to provide a decomposition product comprising the carboxyl functional moiety;
• reacting at least a portion of the decomposition product with at least a portion of the diene rubber to produce the functionalized rubber;
• dropping the mix composition from the internal mixer;
• and
• cooling the mix composition.