ASTM D297 Rubber Products Chemical Analysis

The qualitative and quantitative examination of the composition of rubber products from the "R" family is covered by ASTM D297 test techniques. Many of these test procedures may be used to examine crude rubbers, both natural and manufactured. The values expressed in SI units should be considered standard.

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Scope:

In the ASTM D297 test method, a product’s rubber content is determined by subtracting the total of non rubber ingredients from 100 percent. This procedure may be used on NR, IR, SBR, and BR goods. If IIR compounds are extracted with methyl ethyl ketone rather than acetone, it can also be used. This test technique is used for quality control in rubber product manufacturing operations, raw rubber research and development testing, and evaluating the impacts of additives to a rubber compound, especially the carbon black level in rubber masterbatches.

Procedure:

In ASTM D297 Part A is made up of general test techniques for determining some or all of the key elements of a rubber product and the determination of individual polymers included in a rubber product is covered in Part B.

Part A. General Test Methods:	Sections
Rubber Polymer Content by the Indirect Method	11 – 13
Determinations and Report for the General Method	14 and 15
Density	16
Extract Analysis	17 – 26
Sulfur Analysis	27.1 – 33
Fillers Analysis	34 – 40
Ash Analysis	41 – 51
Part B. Determination of Rubber Polymers	52 – 58

Specimen Size:

Specimen size should be as per the requirements. In this ASTM D297 test, a sample volume of 40 to 120 cc may be used, with a sample size of approximately 100 cc recommended for best repeatability.

Data:

The percentage of rubber is calculated as follows:

Rubber polymer, % = A(100 – B)

Rubber as compounded, % = C/D

Rubber polymer by volume, % = CE/F

Rubber by volume, % = GE/F

Conclusion:

The ASTM D297 procedures given here encompasses the examination of a variety of rubber goods to identify the number and type of non rubber components and to compute the amount of rubber constituent indirectly from these data.