Analysis of Elastomer Vulcanizate Composition by TG-DTG Techniques

Abstract

Two common problems and probable solutions in the TG-DTG analysis of unknown elastomer vulcanizates have been discussed. The first problem concerns the difficulty in quantitatively determining the oil and elastomer in compounds where their volatilization temperature ranges overlap. After a review of the published works in this area, isothermal TG (with or without vacuum) is recommended. The “High Resolution” TG also shows promise and should be explored further. The second problem concerns separate determination of the elastomer-carbon residue and added carbon black in the compound, since both often oxidize together. Subtraction of the predetermined elastomer-carbon residue from the total weight loss in oxygen, was suggested in the literature. However, the quantity of char found depends on the type of the elastomer, its concentration, and the curative composition, as well as the TG temperature profile. The problem is not, therefore, fully resolved. Experiments using a slow feed of lean oxygen gas and isothermal conditions were also suggested in the literature. Under this condition, oxidation of carbon black and char may occur at slightly different temperatures and overlapping is minimized. However, this could be achieved only for large- and mediumparticle-size blacks (soft blacks) which oxidize at higher temperatures and not for the smaller particle size blacks used mostly in tire treads. Further work using the slow feed of lean oxygen with a superimposed isothermal program and/or vacuum conditions is recommended.

Investigation of new composite materials based on activated EPDM rubber waste particles by liquid polymers

“…The second mass loss at 463 C appears due to polymer degradation and the third mass loss at 633 C is attributed to the carbon black content presented in the sample. From the TGA results we can conclude that the RWP contain a paraffinic oil 50 type which represents 25% of the sample composition. The polymer content in the sample is 29.4% and carbon black content is about 32%.…”

“…The samples were further dried at 50 C for 48 h, cooled in a desiccator and then weighted again. The relative gel content with respect to the initial mass m o was calculated from the difference between m o and m d , where m d is the mass of the sample after drying.…”

Determination of compounding formulation of cured rubber by reverse engineering

“…The second was the confusion concerned with separate determination of carbon residue from the elastomers and added carbon black in the compound. He tried a novel route to minimize the problems, and concluded that, despite the difficulties, TGA/DTGA still remained a very powerful tool for the quantitative determination of most vulcanizates because of its simplicity, and time savings over the classical acetone extraction method . From this study it can be inferred that almost all the works concentrated upon using TGA as the primary tool coupled with some other supporting methods to understand the compositions of the vulcanizates.…”

“…This reflects the relative ease and simplicity of the use of TGA. In general, differential thermo gravimetric analysis (DTGA) has a considerable value for estimating the basic composition of vulcanizates [15][16][17][18][19]. The standard test method for rubber compositional analysis by thermogravimetry is ASTM D 6370.…”

Application of differential scanning calorimetry and differential thermogravimetry techniques to determine the ratio of blend components in reactive chlorinated elastomer blends

“…The semicrystalline polar moiety degrades faster than the mere hydrocarbon at relatively lower temperature. Sircar et al2 has worked on the analysis of vulcanizates based on binary blends by a thermogravimetric analysis (TGA)–differential thermogravimetry (DTG) technique. The potential of the TGA‐DTG procedure for quantitative analysis of binary elastomer vulcanizates was also investigated by Maurer3, 4 for the ethylene‐propylene‐diene monomer (EPDM)/NR blend and by Brazier and Nickel5 for NR/butyl rubber (IIR), NR/butadiene rubber (BR), NR/styrene‐butadiene rubber (SBR), etc.…”