BS ISO 11235:2016 pdf download

BS ISO 11235:2016 pdf download.Rubber compounding ingredients — Sulfenamide accelerators — Test methods
1 Scope
This International Standard specifies the methods to be used for the evaluation of sulfenamide accelerators:
— MBTS: benzothiazyl disulphide;
— CBS: N-cyclohexylbenzothiazole-2-sulfenamide;
— TBBS: N-tert-butylbenzothiazole-2-sulfenamide;
— DIBS: N,N’-diisopropylbenzothiazole-2-sulfenamide;
— DCBS: N,N’-dicyclohexylbenzothiazole-2-sulfenamide;
— MBS: N-oxydiethylenebenzothiazole-2-sulfenamide.
NOTE Although MBTS is not a sulfenamide, it is the primary decomposition product of these accelerators and quantitatively determined by the method specified in 5.2.
The analytical methods are applicable for most commercial sulfenamide accelerators:
— sulfenamides of primary amines (type I);
— sulfenamides of unhindered secondary amines (type II);
— sulfenamides of hindered secondary amines (type III).
The method (5.2) to determine purity by high performance liquid chromatography (HPLC) is the preferred method.
2 Normative references
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 385, Laboratory glassware — Burettes
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1772, Laboratory crucibles in porcelain and silica
ISO 3819, Laboratory glassware — Beakers
ISO 4788, Laboratory glassware — Graduated measuring cylinders
ISO 4793, Laboratory sintered (fritted) filters — Porosity grading, classification and designation
ISO 6556, Laboratory glassware — Filter flasks
5.1.5.1.6 Titrate potentiometrically the unreacted hydrochloric acid with the 0,5 mol/dm 3 sodium hydroxide (5.1.3.1.7). With continued stirring, add the sodium hydroxide stepwise in increments of 1 cm 3 , and record the resultant equilibrium potential (mV) after each addition. Approaching the end point, add titrant in increments of 0,1 cm 3 , recording the potential (mV) 20 s after each addition until the end point has been passed. The end point of the titration is the point of inflection of the titration curve, plotted automatically or manually as the measured potential (mV ) against the volume in cubic centimetres of sodium hydroxide solution. At this point, the first derivative curve reaches a maximum while the second derivative curve is zero (falling from a positive to a negative value). The end point shall be calculated from the second derivative on the assumption that the change from a positive to a negative value bears a linear relationship with the addition of sodium hydroxide in the 0,1 cm 3 interval (V 3 ) passing through the inflection point.
5.1.5.2 Method B
5.1.5.2.1 Grind a test sample and weigh approximately 2 g of the blended powder to the nearest 0,1 mg.For TBBS, weigh approximately 1,6 g of the test sample. Transfer it to the beaker (5.1.4.4).