Rates of initiation of the cationic polymerization of isobutene

• Published in: Journal of polymer science. Polymer symposia 1976, Vol.56 (1), p.183-189
• Main Authors: Russell, Kenneth E., Vail, Linda G. M. C.
• Format: Article
• Language: English
• ISSN: 0360-8905; 1936-0959
• DOI: 10.1002/polc.5070560119

The substance 2,6‐di‐tert‐butylphenol acts as a strong retarder for the cationic polymerization of isobutene. Spectroscopic studies show that the growing polymer cation attacks the phenol at the basic 4‐position. Analysis of the kinetic and degree of polymerization results yields estimates of the rates of initiation of the polymerization. The initiation reaction in the polymerization of isobutene in ethyl chloride at −78.5°C with stannic chloride and a coinitiator appears to be a first‐order process. Rate constants for the initiation reaction include 4 × 10−6sec−1 for water as coinitiator, 3.8 × 10−5sec−1 for 2,6‐dimethylphenol, 7.5 × 10−5sec−1 for 2,4,6‐trimethylphenol, 3.1 × 10−5sec−1 for 2,3,5,6‐tetramethylphenol, 7 × 10−5 sec−1 for 2,3,4,6‐tetramethylphenol, and 1.5 × 10−3sec−1 for acetic acid.