Synthesis of high molecular weight polyisobutylene with Al(C6F5)3-based initiating systems under mild conditions
writer：Ling Cai, Bo Liu, Xinli Liu*, Dongmei Cui*
keywords：Cationic polymerization Isobutylene Polyisobutylene High molecular weight
source：期刊
Issue time：2022年
We report here by using a binary initiating system containing a sterically bulky Lewis super acid Al(C6F5)3 together with cumyl chloride (CumCl), the cationic polymerization of isobutylene was realized at temperatures varying from -60 ?C to 15 ?C in a non-halogenated solvent to afford polymers with medium molecular weights from 0.9 ×104 to 14.8 ×104 g?mol-1. Moreover, addition of EDs (EDs =OPh2, SPh2 and NPh3) to the above system generated ternary systems, leading to obvious improvement of the catalytic performances. Among these systems, Al-CumCl-OPh2 was mostly efficient to transfer up to 20,000 equiv. IB into PIBs with high molecular weights up to 35.5 ×104 g?mol-1. at -40?C. The activation energies (Ep) for the polymerization degree with different initiating systems were determined, suggesting that the molecular weight of PIB was strongly dependent on the polymerization temperature.
