BS ISO 20163:2016 pdf free

BS ISO 20163:2016 pdf free.Vulcanized rubber一Determination of free sulfur by gas chromatography
This document specifies chromatographic methods of determination of the inorganic free sulfur (Sx) not consumed during the vulcanization of the rubber.
NOTE 1 The amount of free sulfur is generally very low in a vulcanized rubber. Its direct determination by HPLC is possible, which is not the case with GC without prior derivatization.
NOTE 2 In this document “free sulfur” is used instead of “inorganic free sulfur”.
NOTE 3 The residual curing agent containing sulfur is not concerned by this measure.
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1407, Rubber一Determination of solvent extract
The free sulfur is quantified following two experimental procedures: GC / MS or FID (Method A) and HPLC / UV (Method B). Methods A and B give identical results for the same sample.
A sample of vulcanized rubber is first extracted using an appropriate solvent according to ISO 1407 (Method A and Method B). To the obtained solution a known quantity of triphenylphosphine (TPP) is added. TPP reacts with free sulfur to form stable compound, triphenylphosphine sulfide (TPPS) see Figure 1.
A test piece of vulcanized rubber is weighed (4 g is currently used), divided into pieces before and extracted according to ISO 1407 (Method B).
The solution obtained is then evaporated under partial vacuum using a rotary vacuum. The residue is diluted using 1 ml of THF.
NOTE The use of SPE (solid -phase extractor) cartridge, having a volume capacity of approximately 2 ml or 5 ml,could improve the purification of the extract.
Solution is introduced in a flask of 10 ml; 4 ml of solution of TPP 10-1 mol/l is added to this solution. Complete up to 10 ml with THF. To have a total derivatization, it could be necessary to use a volume of TPP more important to be in excess related to free sulfur in the sample.
The tests shall be duplicated. Two test pieces per sample are extracted and derivatizated.BS ISO 20163 pdf download.