Living cationic polymerization of isobutylene in seconds based on microflow system

Abstract

An initiating system composed by ethylaluminum sesquichloride (Et3Al2Cl3)//2,6-dimethylpyridine (DMP) is established for fast living cationic polymerization of isobutylene. The polymerization can be accelerated at utmost to finish in only 4 s with extremely narrow molecular weight distribution in microflow system. Investigations on influence factors reveal that mixing intensity that dependent on Re affects the molecular weight distribution significantly. DMP has two-stage effect, corresponding to its interactions with protonic impurity and Lewis acid respectively. Polymerization rate can be facilely adjusted by changing the volume ratio of mixed solvent of n-hexane and CH2Cl2 from 8:2 to 7:3 with the assurance of livingness. This polymerization system can even operate at elevated temperature as high as −55 °C without the loss of livingness, which is of great beneficial to the commercialization of polyisobutylene-based functional polymer materials.