New methods for preparing thermoset elastomer products from brominated poly(isobutylene-co-isoprene) (BIIR) are described, wherein control of cross-linking dynamics is gained using latent forms of ammonia, primary amines, and cyclic amidines. BIIR cross-linking by repeated alkylation of standard nitrogen nucleophiles is too rapid at standard polymer processing temperatures, whereas CO(2)-derived salts are shown to be sufficiently inactive under these conditions to support conventional BIIR compounding. Examples include the carbonate, bicarbonate and carbamate salts of ammonia; carbamate and carbamate esters of hexadecyl amine; and the bicarbonate salt of 1,8-diazabicyclo[5.4.1]undec-7-ene. Thermal decomposition of these latent curatives releases CO(2) and the desired nucleophile to support high cross-linking rates and yields at standard cure temperatures. Thermogravimetric analysis of salt decomposition, rheological measurements of cross-link density, and spectroscopic analysis of polymer dehydrohalogenation products are used to define the relationship between latent nucleophile activation and BIIR cure dynamics. POLYM. ENG. SCI., 51: 1592-1598, 2011. (C) 2011 Society of Plastics Engineers