BS ISO 4661-2:2018 pdf download – Rubber, vulcanized — Preparation of samples and test pieces Part 2: Chemical tests
This document specifies a method of preparing samples from vulcanized rubber for use in chemical tests.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1407:2011, Rubber — Determination of solvent extract
3 Terms and definitions
No terms and definitions are listed in this document.
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4 Preparation of samples
4.1 Soft vulcanized rubber
The sample shall be comminuted with scissors, a rotating rasp, a suitable grinder or by cryogenic crushing to pass a sieve with an approximately 1,7 mm opening. Alternatively, it shall be sheeted to a thickness not exceeding 0,5 mm by passing between cold, tightly closed rolls of a laboratory mill. The type of grinder or mill used is immaterial, provided that the sample does not become contaminated or unduly heated.
4.2 Ebonite The sample shall be rasped to powder which will pass a sieve with an approximately 400 μm opening. The powder shall be treated with a magnet to remove any iron particles.
4.3 Rubberized composites Where it is not possible to separate the rubber mechanically, the following procedure shall be carried out. The rubber shall be separated by exposing it to the vapour only of a suitable solvent. For composites based on NR, SBR and BR, acetone or ETA (ethanol‑toluene azeotrope) will be suitable solvents. For other types of rubber, refer to ISO 1407:2011 (Annex A) for suitable solvents.
The time of exposure should be kept as short as possible to avoid any possibility of extracting plasticizers from the rubber compound. Afterwards, the swollen rubber shall have the solvent completely removed in air at room temperature and treated as described in 4.1.
In cases where the rubber is chemically bonded to the substrate, it should be noted that the composition of the rubber in the region of the bond can be substantially different from that in the bulk of the material. In all cases, sampling shall be appropriate to the test being carried out. Even if the substrate can be removed “clean”, the remaining rubber might consist of more than one formulation, and the blending carried out subsequently in accordance with 4.1 can result in a sample for analysis which is not representative of any one original formulation. Such composite layers can be revealed by microscopic examination of a series of cross‑sections of the material. It will then be possible, by careful buffing or cutting, to produce a sample of one or more rubber components for individual analysis.
Where it is impossible to separate the rubber from the substrate, the material shall be cut into small cubes to pass a sieve with 2 mm openings, and analysed as a whole. In this case, the proportion by mass of rubber in the composite can be determined by disintegration of the rubber in a hot high boiling solvent, and weighing before and after the treatment. It should be noted that there might be partial dissolution of any organic material in the composite (for example, fabric), and the results should be interpreted with caution. Where available, a sample of the non‑rubber portion of the composite should also be analysed similarly. In reporting the results of any analysis, the method of separation used shall be specified. If separation was impossible, it shall be made clear that the sample analysed was a heterogeneous blend of rubber and substrate and the possibility of error due to inhomogeneity or inadequate separation of materials should be pointed out.BS ISO 4661-2 pdf download.