Internal impurities in polystyrene

Photodegradation of polystyrenes depends very much upon how they were synthetized and what kind of internal (structural) impurities they contain [1292, 2242, 2243, 2259]. Radically prepared polystyrenes can contain the following abnormal structures  

Double bonds may cause an a-hydrogen atom, which is also a tertiary hydrogen atom, to be more labile by lowering the dissociation energy of 

ESR spectra of polystyrene UV irradiated (a) in vacuum at 77 K [492] and (b) in air at room temperature [1360]. [(a) Reproduced with permission from American Institute of Physics, 1968 (b) Reproduced with permission from [1360] published by Elsevier Science Publishers Ltd, 1979.] 

The fluorescence emission of polystyrene (Fig. 3.48) reveals small amounts of monomeric styrene and trans-stilbene groups (3.75) which probably 

The fluorescence in the blue spectral region may be due to chromophores formed by conjugated double bonds and phenyl groups (3.76) [1211]. 

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