Elastomers: Sulphur or peroxide cross-linked? An analytical approach
The analytical methods presented in this study lead to a characterisation of the vulcanisation system of unknown elastomers. The chemical determination of sulphur gives a first impression of the system. However, it cannot be proved with any degree of certainty weather a product is sulphur cross-linked or not. Other wet chemical methods (colour reactions) are more suitable for quality control of already known systems. Most spectrometric methods (infrared spectrometry, Raman spectrometry, nuclear resonance spectrometry) are only of use for special applications and for research. A more precise characterisation is obtained by means of chromatographic methods, i.e. by identifying the products, which originated from thermal degradation of the cross-linking reagents (sulphur, sulphur donators, peroxides. Evolved-Gas-Analysis (EGA) and pyrolysis gas chromatography with adequate detectors proved to be very successful as chemical-analytical methods for such investigations. In order to make a reliable statement about the vulcanisation system of unknown elastomeric material, the results of several analytical methods have to be collected and evaluated.