ISO 21561-2:2024

Styrene-butadiene rubber (SBR) — Determination of the microstructure of solution-polymerized SBR — Part 2: Fourier transform infrared spectrometry (FTIR) with attenuated total reflection (ATR) method

Scope

This document specifies procedures for the quantitative determination of the microstructure of the butadiene portion and the content of styrene in solution-polymerized SBR (S-SBR) by Fourier transform infrared spectrometry (FTIR) with attenuated total reflection (ATR) method. The styrene content is expressed in mass fraction relative to the S-SBR. The contents of three microstructure types, i.e. vinyl, trans and cis, are expressed in mol fraction relative to the butadiene portion in the S-SBR. This method is only applicable to raw rubbers.
NOTE 1       Precision as shown in Annex A is not always possible to obtain for S-SBRs containing polystyrene block or styrene content more than 45 %.
NOTE 2       Only “vinyl”, “trans” and “cis”, are used in this document. However, the expression of vinyl, trans and cis mean as follows in general:
—      vinyl: vinyl unit, vinyl bond, 1,2-unit, 1,2-bond, 1,2-vinyl-unit or 1,2-vinyl-bond;
—      trans: 1,4-trans unit, 1,4-trans bond, trans-1,4 unit or trans1,4 bond;
—      cis: 1,4-cis unit, 1,4-cis bond, cis-1,4 unit or cis-1,4 bond.