Absorption of UV Radiation by Polymers

Owing to vibrational and electronic couplings, UV absorption bands of polyatomic molecules in ffie condensed state are generally quite broad, with width at half-maximum commonly exceeding 60-80 nm. Even with this broadness, polymers such as polyolefins, polyacetals, poly(vinyl chloride), or polyacrylonitrile 

Values in brackets refer to the secondary absorption band. 

Internal impurities These are part of the molecular structure, situated either along the chain or at chain end(s), and may consist of  

Carbonyl containing groups formed during material transformation. Processing, with elevated temperature and high shearing stresses, provides ample opportunities for thermal oxidation. Even at ambient temperature, some polymers such 

External impurities Such impurities are contained in the sample but not incorporated in the polymer structure. 

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