ISO 11235 pdf download

ISO 11235 pdf download.Rubber compounding ingredients — Sulfenamide accelerators — Test methods 1 Scope 1.1 This International Standard specifies the methods to be used for the evaluation of sulfenamide accelerators. 1.2 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) 1.2.1 MBTS: Benzothiazyl disulfide NOTE Although MBTS is not a sulfenamide, it is the primary decomposition product of these accelerators and quantitatively determined by the method specified in 4.2. 1.2.2 CBS: N -cyclohexylbenzothiazole-2-sulfenamide 1.2.3 TBBS: N – tert -butylbenzothiazole-2-sulfenamide 1.2.4 DIBS: N , N ‘-diisopropylbenzothiazole-2-sulfenamide 1.2.5 DCBS: N , N ‘-dicyclohexylbenzothiazole-2-sulfenamide 1.2.6 MBS: N -oxydiethylenebenzothiazole-2-sulfenamide 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 385-1 :1 984, Laboratory glassware — Burettes — Part 1 : General requirements . ISO 648:1 977, Laboratory glassware — One-mark pipettes . ISO 1 772:1 975, Laboratory crucibles in porcelain and silica . ISO 381 9:1 985, Laboratory glassware — Beakers 4 Test methods for purity 4.1 Method to determine purity by reduction with MBT and titration 4.1.1 Scope The following method is suitable for determining the purity and free amine in sulfenamides commonly used in the rubber industry and is applicable to CBS, DCBS, MBS and TBBS. 4.1.2 Principle After neutralization of the free amine, the sulfenamide is reduced by means of a solution of mercaptobenzothiazole (MBT). An excess of hydrochloric acid is added and the unreacted hydrochloric acid is then titrated with sodium hydroxide using one of the two following methods: – method A: potentiometric titration; – method B: titration using an indicator. 4.1.3 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1.3.1 Basic reagents for methods A and B 4.1.3.1.1 Mercaptobenzothiazole (MBT), min. assay 99,0 %. 4.1.3.1.2 Absolute ethanol. 4.1.3.1.3 Toluene. 4.1.3.1.4 Hydrochloric acid, standard volumetric solution, c(HCl) = 0,1 mol/dm 3 . 4.1.3.1.5 Hydrochloric acid, standard volumetric solution, c(HCl)...