Method for preparing high-activity polyisobutene by using bifunctional initiator and application

The invention belongs to the technical field of synthesis of polymer homopolymers. The invention relates to a method for preparing high-activity polyisobutene, in particular to a method for preparinghigh-activity polyisobutene with exo-olefin end groups at the two ends through cationic polymerization of a bifunctional initiator. According to the method, isobutene is used as a raw material; at thetemperature of -30 DEG C to 10 DEG C and under different bifunctional initiator initiating systems and different charging sequences, high-activity polyisobutene is prepared through cationic polymerization; two ends of the prepared high-activity polyisobutene are respectively provided with exo-olefin end groups; the content of the olefin structures outside the two ends ranges from 70 mol% to 99 mol%, and the conversion rate of isobutene ranges from 60% to 100%; the number-average molecular weight of high-activity polyisobutene is controllable, the number-average molecular weight ranges from 500 g/mol to 5,000 g/mol, mo