“…There are several examples involving the functionalization of the PIB terminus with carboxylic acid moieties, , as well as the polymerization of t -butyl acrylate and t -butyl methacrylate from atom transfer radical polymerization (ATRP) initiation sites at the terminus or in the middle of the PIB chain, followed by acidic or thermal deprotection to provide carboxylic acid moieties. ,,, Conetworks have been formed by the polymerization of ethoxyethyl-protected methyl methacrylate with methacrylate-terminated PIB, followed by acidic deprotection . There are also examples involving the introduction of pendant carboxylic acids along the backbone of butyl rubber via the grafting of maleic anhydride, followed by the anhydride ring-opening with amines or alcohols. − However, there are still relatively few studies concerning the effects of these carboxylic acid moieties on the properties of these modified materials. ,,, …”