TG/FT-IR characterization of additives typically employed in EPDM formulations

Abstract

SbstractThermogravimetric analysis coupled to Fourier transform infrared spectroscopy (TG/FT-IR) is a very popular technique for rubbers characterization. It involves analyses of the base polymer and additives. Ethylene-propylene-diene (EPDM) rubbers are frequently investigated by TG/FT-IR; however, the focus has been the degradation temperature range of the polymer. In this study, unvulcanized and vulcanized EPDM rubber and its additives were investigated by TG/FT-IR, without solvent extraction, and in a wide temperature range. Initially, the additives were individually characterized. TG/FT-IR identified the characteristic groups of all the additives analyzed and distinguished them from each other. Afterwards, unvulcanized and vulcanized EPDM rubbers were investigated without prior extraction. TG/FT-IR detected absorptions due to the additives tetramethylthiuram monosulfide and 2-mercaptobenzothiazole. Both of these sulfur-containing additives were present in the EPDM formulation at concentrations of 0.7 phr (0.63 wt %). The TG/FT-IR technique had some limitations, because not all the additives in EPDM rubber were detected. Paraffin oil, stearic acid and 2,2,4-trimethyl-1,2-dihydroquinoline functional groups were not observed in either the unvulcanized or vulcanized EPDM. Nevertheless, in addition to the ability of this method to detect sulfur-containing groups, the lack of a pre-extraction reduces the time and effort required for additive analysis in rubbers.

Methodologies for Characterization of Aerospace Polymers/Energetic Materials - a Short Review

“…The interaction of these techniques proved to be useful for this kind of characterization. Sanches et al (2015) developed a methodology of TG/IR in order to evaluate additives in EPDM rubber composition. Unvulcanized and vulcanized EPDM rubbers and their additives were investigated by TG/FT-IR without solvent extraction and in a wide temperature range.…”

“…The topics are organized by methodologies, including also the IR or FT-IR techniques couplings with thin layer chromatography (TLC/IR) (Dutra 1996;Damazio 2015;Damazio et al 2014Damazio et al , 2015 and thermogravimetric analysis (TG/FT-IR) (Sanches 2015;Sanches et al 2014Sanches et al , 2015.…”

Characterization of additives in NR formulations by TLC-IR (UATR)

“…In this study [19] , although good results were reached for sulfur additives such as MBT and TMTM, they were characterized by a complex methodology of its degradation products. Plasticizer was not detected, whereas in the TLC/UATR showed in this current paper, naphthenic oil was separated and characterized.…”

“…After these results, the TLC-IR(UATR) analysis applied to separate and characterize NR additives such as CBS, TMTD and DCP, was considered available to rubber quality control in laboratories because is faster and simpler than methodologies involving other coupling types such as TG/IR [19] . In this study [19] , although good results were reached for sulfur additives such as MBT and TMTM, they were characterized by a complex methodology of its degradation products.…”

Perylene polyphenylmethylsiloxanes for optoelectronic applications

“…2). [50][51][52][53] Specific aromatic vibration bands due to phenyl side groups at 3045, 3070 These bands can be used to differentiate between the samples. At a PMS/PMV ratio of 1/1 no Si-H vibrations can be detected while a decreasing vinyl concentration leads to an increasing number of unreacted Si-H groups.…”