Synthesis of Low Molecular Weight Butadiene Polymers Using Cationic Catalytic Systems Based on Diethylaluminum Chloride.

Rozentsvet, V. A.; Ulyanova, D. M.; Sablina, N. A.; Brunilin, R. V.; Tolstoy, P. M.

The cationic polymerization of butadiene under the action of catalytic systems based on diethylaluminum chloride (AlEt2Cl) in combination with tertiary alkyl halides (AHs) such as tert-butyl chloride, tert-butyl bromide, and 2-chloro-2-methylbutane is found to be an efficient method for the preparation of fully soluble butadiene polymers at a technologically convenient process temperature of 20°C. It is shown that with an increase in the duration of butadiene polymerization process, the weight-average molecular weights and polydispersity of the polymer increase significantly with a simultaneous decrease in the unsaturation of polybutadiene, which is associated with the transfer reaction of the growing chain to the double bond of the polymer during polymerization. A 13C NMR spectral study showed that the macromolecules of polybutadiene synthesized on the AlEt2Cl–tert-butyl chloride catalytic system consist mainly of 1,4-trans units and contain two types of initial tert-butyl units and two types of end chlorine-containing units formed as a result of the transfer reaction of the growing chain to tert-butyl chloride. Based on the data of 13C NMR spectra of polybutadiene, a method for calculating butadiene conversion during polymerization is developed, and a mechanism of the process of cationic polymerization of butadiene is proposed. It is shown that the synthesized "cationic" polybutadiene is characterized by high film-forming properties and can be a promising component in the production of paints and varnishes.

CATIONIC polymers; BUTADIENE; MOLECULAR weights; POLYMERS; ADDITION polymerization; HALOALKANES; VARNISH & varnishing

Kinetics & Catalysis, 2023, Vol 64, Issue 1, p55

0023-1584

Academic Journal

10.1134/S0023158423010068