Development of a Test Method for the Estimation of SBR-BR Blend Ratio in Tyre Tread Formulation and Validating It through Robust Statistical Tools

Abstract

Blends of synthetic rubbers are widely used by rubber product manufacturing industries depending on the end use and product application. The estimation of individual rubber in blends is an important aspect to characterise the correctness of the mixing process. In tyre industry, Styrene butadiene rubber/Polybutadiene rubber (SBR/BR) blend is commonly used to achieve different performance properties, particularly for passenger car tyre. Out of the different quantitative analysis techniques to characterise the blend, one of the widely used techniques Gas Chromatography-Mass Spectrometry (GC-MS) has been used to develop and later validate a method to quantify the SBR/BR blend ratio. Through this GC-MS technique detection capability is measured, with a minimum limit of detection (LOD) of 5.17% and a limit of quantification (LOQ) of 15.67% Styrene butadiene rubber (SBR) in an SBR-BR vulcanizate. It is observed that the bias percentage is highest in case of a lower SBR content sample, i.e. 11.1% while in the case of other sets, it is varying from (–)1.4% to (+)1.5%. During the recovery study, it is observed that with increasing SBR content, recovery is also improving. All requirements for a successful method validation: Accuracy, precision, selectivity, detection capability, calibration range and robustness have been carried out in this entire work.