Evaluation of sample preparation methods for elastomer digestion for further halogens determination

Area of Science:

• Analytical Chemistry
• Materials Science

Background:

• Elastomers, particularly those with high carbon black content, present challenges for accurate elemental analysis.
• Reliable methods are needed for halogen determination (bromine and chlorine) in complex polymer matrices.

Purpose of the Study:

• To evaluate and compare three sample preparation methods for halogen determination in carbon black-rich elastomers.
• To identify the most efficient and accurate digestion technique for subsequent elemental analysis.

Main Methods:

• Evaluated oxygen flask combustion, microwave-induced combustion (MIC), and microwave-assisted extraction.
• Used nitrile-butadiene rubber, styrene-butadiene rubber, and ethylene-propylene-diene monomer elastomers.
• Analyzed bromine and chlorine using ion chromatography (IC), ICP OES, and ICP-MS.

Main Results:

• MIC with 5 min reflux achieved >95% agreement for Br and Cl, with <5% RSD, suitable for IC, ICP OES, and ICP-MS.
• MIC demonstrated high digestion efficiency with <1% residual carbon.
• Extraction methods yielded low recoveries (<45%) and high residues; oxygen flask combustion had higher RSD (20%).

Conclusions:

• Microwave-induced combustion (MIC) is a highly efficient and accurate method for preparing carbon black-rich elastomers for halogen determination.
• MIC provides a versatile single-solution digest compatible with multiple analytical techniques.
• MIC surpasses oxygen flask combustion and microwave-assisted extraction for this application.