The Influence of the Concentration of an ‘n-butyllithium–amine-containing Modifier’ Initiating System on the Copolymerisation of 1,3-butadiene and Styrene

Abstract

The influence of the concentration of an initiating system consisting of n-butyllithium and an amine-containing modifier on the copolymerisation of 1,3-butadiene and styrene in a hexane solvent was studied. The molecular characteristics and the microstructure of specimens of the obtained solution-polymerised styrene butadiene rubber (s-SBR) were determined by gel permeation chromatography on a Breeze liquid chromatograph (Waters) and by IR spectroscopy on a Spectrum GX 100 spectrometer (PerkinElmer) in accordance with ISO 21561/2. It was shown that a reduction in the amount of the initiating system is accompanied with a reduction in the copolymerisation rate and in the monomer conversion, and also with an increase in the average molecular weights of the copolymer. It was established that a reduction in the initiating system concentration in the reaction medium leads to a reduction in the content of 1,2-units in the rubber. A comparative analysis of data for rubber compounds based on the synthesised s-SBR and data for rubber compounds based on standard rubber indicates that their mechanical properties are at the same level. However, the tg δ at 60°C (determined on an RPA 2000 instrument) for rubber compounds based on a trial specimen has a lower value, which will make it possible to produce tyre rubbers providing a lower tyre rolling resistance.