| Butyl rubber is a random copolymer of isobutylene and 1--2% isoprene, which exhibits the air impermeability required for tire inner liner applications. Bromination generates an elastomer that has the enhanced cure reactivity needed to generate useful industrial products.; The unique vulcanization chemistry of this commodity elastomer is attributed to the allylic bromide within bromobutyl rubber (BIIR). However, the low concentration of reactive functionality complicates attempts to characterize polymer reaction products, particularly when the material is vulcanized. Through the use of a model compound that accurately represents the reactive functionality of the elastomer, the isolation and characterization of products derived from the allylic bromide is readily accomplished. In the present work, brominated 2,2,4,8,8-pentamethyl-4-nonene (BPMN) was used as a model for BIIR to study the reactivity of the allylic bromide with respect to substitution reactions with amines and thiolate nucleophiles. Additionally, the products derived from BIIR sulfur cures were isolated and characterized.; Vulcanization of BPMN with sulfur produced sulfidic dimers of varying rank, which underwent rank reduction and decomposition at prolonged reaction times. (Abstract shortened by UMI.)... |
