ASTM D2702

ASTM D2702 – Standard Practice for Rubber Chemicals—Determination of Infrared Absorption Characteristics

Description:

Significance and Use

5.1 This procedure can be used for a variety of applications, including identifying unlabeled material, process control, raw material acceptance, product evaluation, and compositional change during environmental testing.

5.2 Rubber chemicals vary widely in their chemical and physical properties. Infrared spectrophotometers vary in the presentation of a spectrum (some are linear with absorbance, others with transmittance, some use grating for energy dispersion, others use a sodium chloride prism, some obtain a spectrum through a mathematical Fourier Transform, and the like). For these reasons, a single universal method of specimen preparation and set of instrument parameters is not possible.

5.3 By using a specific sampling procedure and operating conditions, a given spectrophotometer will give an absorption curve that is characteristic of the rubber chemical or mixture under investigation.

5.4 The ability to superimpose the infrared spectrum of the test specimen upon that of a reference specimen, obtained under the same conditions, is evidence that the two are identical.

5.5 The presence of additional absorption bands in either the test specimen or the reference specimen indicates the presence of one or more additional components.

Scope

1.1 This practice covers a simple, rapid practice to prove the identity of a rubber chemical before incorporation into a rubber mix by comparison of its infrared absorption spectrum with that of a reference specimen.

1.2 This technique can also be used to detect gross contamination or large differences in rubber chemicals. Thus, it can provide a basis for producer-consumer agreement.

1.3 Wherever “infrared spectrophotometer” is used, “Fourier Transform Infrared Spectrometer (FTIR)” may also be understood.