To improve various physical properties of poly(isobutylene oxide) copolymers of isobutylene oxide and cyclohexene oxide have been synthesized with triisobutylaluminum as catalyst. The molecular weights of the copolymers are rather lower than that of poly(isobutylene oxide) prepared with diethylzinc catalyst. The glass transition temperatures of the copolymers are between those of two homopolymers. The copolymers of isobutylene oxide and vinyl cyclohexene oxide showed better thermal stability. Oligomer of isobutylene oxide has been synthesized for polyol and lubricant application. Acid catalyzed oligomerization gave vary complex mixture. But base catalyzed reaction afforded the pentamer and hexamer rich oligomer mixtures.