Ultraviolet light stabilization varieties

Polystyrene light stabilization has been achieved with a variety of ulfravioler absorbers including the benzophenones, benzotriazoles. and salicylates. While yellowing of polystyrene occurs in many applications, it is particularly noticeable in diffusers used with fluorescent lights. This problem has been effectively solved by using ultraviolet light absorbers. In this instance, superior stabilization is achieved when the ultraviolet absorber is used in conjunction wirh specific antioxidants. 

Difluoramino radicals combine with a variety of other radicals, with the product stability apparently directly related to the stability of the substrate radical. For instance, nitric oxide and NF2 form a compound, difluoronitrosamine, only at low temperatures (3) at room temperature and atmospheric pressure the two radicals do not interact. Chlorine and N2F4 react under the influence of ultraviolet light to produce chlorodifluoramine, CINF2 (13). The equilibrium reaction is favored by high concentrations of chlorine and by high temperature (80° C). Because of this unfavorable equilibrium, the reaction of difluoramine and boron trichloride provides a more satisfactory route to chlorodifluoramine (11). 

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