Molecular rearrangement reactions, thermal degradation

Thermal degradation reactions of polymers can be divided into two broad groups molecular rearrangement reactions and reactions which involve ho-mol5d ic scission of bonds to produce free radicals. In both cases the chemistry... 

McNeill and Rincon studied thermal degradation of PC by means of TGA, TVA, DSC, FT-IR, mass spectrometry (MS) and gas chromatogra-phy-MS (GC-MS) method (see Fig. 2.5). PC is stable up to 300°C. Above that temperature, small quantities of phenol and p-cresol were detected, at 375-400°C CO2 appeared and then at T > 455°C CO and CH4 were formed the peak on the DTG curve was at F = 462°C. At 500°C the main products are q chc dimer and bisphenol A, with small quantities of CO2, p-cresol, p-ethyl phenol, phenol, p-vinyl phenol, p-isopropyl phenol, CO and CH4. In the absence of air and moisture, degradation of PC proceeds by hemolytic decomposition of the polymer chain, radical reactions, fragmentations and molecular rearrangements. 

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