Antidegradants, determination

Plasticiser/oil in rubber is usually determined by solvent extraction (ISO 1407) and FTIR identification [57] TGA can usually provide good quantifications of plasticiser contents. Antidegradants in rubber compounds may be determined by HS-GC-MS for volatile species (e.g. BHT, IPPD), but usually solvent extraction is required, followed by GC-MS, HPLC, UV or DP-MS analysis. Since cross-linked rubbers are insoluble, more complex extraction procedures must be carried out. The determination of antioxidants in rubbers by means of HPLC and TLC has been reviewed [58], The TLC technique for antidegradants in rubbers is described in ASTM D 3156 and ISO 4645.2 (1984). Direct probe EIMS was also used to analyse antioxidants (hindered phenols and aromatic amines) in rubber extracts [59]. ISO 11089 (1997) deals with the determination of /V-phenyl-/9-naphthylamine and poly-2,2,4-trimethyl-1,2-dihydroquinoline (TMDQ) as well as other generic types of antiozonants such as IV-alkyl-AL-phenyl-p-phenylenediamines (e.g. IPPD and 6PPD) and A-aryl-AL-aryl-p-phenylenediamines (e.g. DPPD), by means of HPLC. 

Table 2.3 as a completely worked out example using quantitative solvent extraction, ash content determination, TGA, FTIR, XRF, GC-MS, HS-GC-MS, PyFTIR, ICP, and s-NMR. Information on the cure and antidegradant systems was obtained (assigned species/possible origin), as follows cyclohexane thiol/CBS accelerator benzothiazole/MBT, MBTS or CBS accelerators N, A-dimethylformamide/TMTD accelerator phthalim-ide/Santoguard PVI and IV-phenylbenzene amine/possi-bly a diphenyl/acetone amine antioxidant. 

ISO 11089 (1997) Determination of antidegrad-ants in synthetic elastomers with HPLC. 

ISO 4645 (1984) Procedure for the determination of antidegradants in rubbers and rubbery products by means of TLC. 

METHOD 47 - DETERMINATION OF AMINE ANTIOXIDANTS AND ANTIDEGRADANTS IN RUBBER. GEL PERMEATION, CHROMATOGRAPHY. ... 

This method is capable of determining down to 0.02% of amine antioxidants and antidegradants in rubbers with an accuracy of 5%. 

Thermogravimetric analysis measures the amount and rate of weight change in a material as a function of temperature, or time, in a controlled atmosphere. These measurements are mainly used to determine the composition of polymer products and precursors (e.g. additive master batches), but can also be used to measure thermal stability and study the effects that additives such as antidegradants have on this property. 

Thermal degradation Determination of thermal stability Evaluation of antidegradants... 

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