Patent ID: 8648141

Claim:
A composition comprising a styrene butadiene rubber wherein the styrene butadiene rubber is characterized before any vulcanization by the following: (a) two or more portions in one polymer chain which are incompatible with each other; (b) two or more glass transition temperatures that vary by at least about 6° C.; (c) two or more δ (SBR) values which differ by at least more than about 0.65 (J/cm 3 ) 0.5 ; and (d) two or more portions which vary in styrene content based on the total weight of each portion by at least about 20 weight percent; wherein the styrene butadiene rubber comprises at least a portion which is compatible with a second rubber and a portion which is not compatible with said same second rubber; wherein at least a portion of the styrene butadiene rubber is chain end functionalized, and wherein the portion of the styrene butadiene rubber that is chain end functionalized comprises less styrene content than a portion of the styrene butadiene rubber that is not chain end functionalized.