Chapter 9: Thermal Methods

9.1 Pyrolysis-Gas Chromatography-Mass Spectrometry

Py-GC employing various detection systems is the technique usually used to qualitatively and quantitatively analyse major components and low-level additives in polymers [1-3]. The technique utilises thermal energy to break down polymers to monomers and small oligomers. The mixture of pyrolysis products is directly passed into a gas chromatograph (GC) for separation. However, there are numerous low-level co-monomers and additives that may not be appropriately separated at the same time as the major monomers. These low-level co-monomers and additives frequently appear with poor peak shape under the chromatographic conditions established for analysis of the major monomers hence the interest in combining this technique with MS (such as a polar additive in a non-polar capillary column). Additionally, these peaks may have been overlooked because they exist as converted products in the chromatogram after the pyrolysis-induced reaction (such as vinyl acetate converted to acetic acid).

Ogawa and co-workers [4] used Py-GC-MS to analyse the components of ozone deteriorated nitrile-butadiene rubber sheet containing additives. There were three peaks related to the quinoline antioxidant in the program. They noted that the mechanical strength of the sheet became zero when the antioxidant level reached 50% of its original level.

Franich and co-workers [5] described two simple methods using internal standards for the quantitative analysis of 2,6-di- tert-butyl-4-methylphenol...