IR spectrum

IR spectroscopy uses infrared light to analyse the molecular vibrations of the chemical bonds in the material. These vibrations occur at specific wavelengths that are characteristic of particular chemical groups.

Steps of IR analysis:

• Sample preparation: the material is prepared as a thin film, powder or in a carrier solution.

• Measurement: infrared radiation is passed through the sample and the absorbed wavelengths are recorded.

• Spectrum analysis: the resulting spectrum shows absorption peaks that correspond to the various chemical groups of the material.

The IR spectrum is an indispensable tool for analysis and quality assurance in the rubber industry. It is used in various areas:

Material identification

• Identifying elastomer types: distinguishing between materials such as EPDM, NBR, CR and silicone on the basis of their specific spectra.

• Identifying fillers and additives: analysis of carbon black, plasticisers, vulcanising agents and other compound ingredients.

Quality control

• Checking raw materials: ensuring that the materials used meet the specifications.

• Analysing finished parts: checking whether seals and other rubber products are correctly vulcanised and free of contamination.

Failure analysis

• Causes of defects: examining faulty seals or components to identify material defects or incompatibilities.

• Ageing analysis: detecting oxidation or other degradation processes in aged products.

Using the IR spectrum offers numerous advantages:

• Speed: results can be obtained within a few minutes.

• Variety of materials: analysis of a wide range of elastomers and additives.

• Precision: high accuracy in identifying substances.

• Non-destructive: the method requires only small sample quantities and does not destroy the material.

Although IR spectroscopy is a powerful tool, there are some challenges:

• Sample preparation: precise preparation is crucial to minimise interference.

• Complex compounds: interpreting spectra can be difficult when many components are present.

• Sensitivity: some fillers or additives can be difficult to detect at low concentrations.

Feature	IR spectrum	Thermogravimetric analysis (TGA)	X-ray fluorescence spectroscopy (XRF)
Analytical focus	Organic compounds, elastomers	Mass loss due to thermal decomposition	Inorganic elements
Sample preparation	Minimal	Simple	Complex
Typical applications	Material identification, additive analysis	Thermal stability	Filler analysis
Sensitivity	High for organic compounds	High for thermal properties	High for elements

• Which materials can be analysed with IR spectroscopy? All elastomers, additives and fillers that absorb infrared light can be examined.

• How detailed is the analysis? IR spectroscopy can identify specific chemical groups and their concentrations.

• Is the method non-destructive? Yes, IR analysis requires only minimal samples and does not damage them.

• How does the IR spectrum support quality control? It ensures that raw materials and finished products meet the specifications and are free of contamination.

The IR spectrum is an indispensable tool in the rubber industry, and particularly for us at SIEGEL Dichtungen. It offers a fast, precise and non-destructive way of analysing materials and ensuring their quality. Whether for identifying elastomers, checking additives or analysing failures, IR spectroscopy makes a major contribution to product quality and process reliability.