Cationic polymerization of β-pinene in the presence of alkylaluminum chlorides as catalysts
Cationic polymerization of β-pinene, a naturally occurring monomer, was studied in the presence of different alkylaluminum chlorides ((<sup> i </sup>Bu)<sub>3</sub>Al<sub>2</sub>Cl<sub>3</sub>, Et<sub>3</sub>Al<sub>2</sub>Cl<sub>3</sub> и Мe<sub>2</sub>AlCl) in the solvent mixture dichloromethane/methylcyclohexane (DCM/ MCH) at -78 °C. The effect of catalyst concentration [(<sup> i </sup>Bu)<sub>3</sub>Al<sub>2</sub>Cl<sub>3</sub>] and various electron donors on the polymerization rate and molecular-weight characteristics of synthesized poly(β-pinenes) was investigated. Controlled cationic polymerization of β-pinene was carried out in the presence СumCl/Мe<sub>2</sub>AlCl initiating system. The polymers with controlled molecular weight up to 6400 g/mol and relatively low polydispersity (<i>M</i><sub>w</sub> /<i>M</i><sub>n</sub> < 1,42)) were synthesized. Microstructure of synthesized poly(β-pinene) was investigated by <sup>1</sup>H NMR spectroscopy.