Synthesis of polyisobutylene with arylamino terminal group by combination of cationic polymerization with alkylation

Abstract

Abstract The controlled cationic polymerization of isobutylene (IB) initiated by H 2 O as initiator and TiCl 4 as coinitiator was carried out in n ‐Hexane/CH 2 Cl 2 (60/40, v/v) mixture at −40 °C in the presence of N,N ‐dimethylacetamide (DMA). Polyisobutylene (PIB) with nearly theoretical molecular weight ( M n = 1.0 × 10 4 g/mol), polydispersity ( M w / M n ) of 1.5 and high content (87.3%) of reactive end groups ( tert ‐Chlorine and α ‐double bond) was obtained. The Friedel‐Crafts alkylation of triphenylamine (TPA) with the above reactive PIB was further conducted at different reactions, such as [TPA]/[PIB], solvent polarity, alkylation temperature, and time. The resultant PIBs with arylamino terminal group were characterized by 1 H NMR, UV, and GPC with RI/UV dual detectors. The experimental results indicate that alkylation efficiency ( A eff ) increased with increases in [TPA]/[PIB], reaction temperature, and reaction time and with a decrease in solvent polarity. The alkylation efficiency could reach 81.0% at 60/40(v/v) mixture of n ‐Hex/CH 2 Cl 2 with [TPA]/[PIB] of 4.49 at 50 °C for 54 h. Interestingly, the synthesis of PIB with arylamino terminal group could also be achieved in one pot by combination of the cationic polymerization of IB initiated by H 2 O/TiCl 4 /DMA system with the successive alkylation by further introduction of TPA. Mono ‐, di ‐ or tri ‐alkylation occurred experimentally with different molar ratio of [TPA]/[PIB]. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 936–946, 2008