Off-line TLC-IR (UATR) characterization of additives in EPDM rubber

Sulfur donor accelerators and vulcanization agents, such as peroxides, due to their chemical characteristics and good thermal stability properties in rubber formulations, are essential to provide solutions in different sectors, such as aerospace and automotive, since they reduce the polymer degradation process (reversal), which can influence the performance of the elastomeric material. In this way, the use of methodologies for the components knowledge of a formulation is imperative for the structure proper establishment/property relationship of the elastomeric artifacts. The development of methodology that can separate and characterize the rubber formulation components is a constant challenge, still allows gaps, and is usually done by conventional but not coupled instrumental techniques. In this scenario, this paper aimed to contribute to the use of the off-line coupling of thin-layer or thin-layer chromatography (TLC)/infrared spectroscopy (FT-IR), by universal attenuated total reflection (UATR) for N-cyclohexyl-2-benzothiazolesulfenamide (CBS), tetramethyl thiuram disulphide (TMTD) and dicumyl peroxide (DCP), in formulations of ethylene and propylene diene monomer (EPDM) rubber containing the plasticizer naphthenic oil. This plasticizer was characterized in formulations that presented higher content of this compound, but the eluting systems were not effective in separating DCP. However, better separation of CBS and TMTD was observed. •Eluent systems toluene/ethyl acetate and toluene used in TLC analysis can separate additives from vulcanized rubber.•FT-IR/UATR analysis can validation TLC results in the study of rubber additives.•TLC/FT-IR/UATR can be successfully applied to the analysis of CBS and TMTD in EPDM formulation.•TLC/FT-IR/UATR is a valuable methodology to investigate additives in vulcanized rubber.