Pyrolysis - Gas Chromatogarphy Py-GC

This technique has been used to study PS [40]. Pyrolysis of PS derived from n-butyl and four from n-butyl groups and a polystyrene unit is shown in Table 8.1. 

Based on these results, M values could be estimated using relative molar intensities of these nine characteristic peaks (i = 1-9) against those of the major peaks (i = 1-22). In this case, minor peaks other than i = 1-22 were ignored because the total relative intensity of these peaks was less than a few percent. Because the degree of polymerisation (Dp) of the PS sample is defined as the number of styrene units per end group. Dp can be calculated by the following equation  

Of the various pyrolysis products produced, one in particular, peak 8 (C4H9- CH2C(Ph) = CH2) (2-phenyl heptanes) was the most characteristic of the nine products mentioned previously. It gave a linear relationship between and the relative intensity of this peak to the total intensity of all 22 peaks in the programme. 

Li and Rinaldi [41] used three-dimensional (3D) NMR to determine the chain-end structure of C-labelled PS. 

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