Degradation photodegradation

Degradation photodegradation half-life on grass (2,3,7,8-)=44 h(k2 = 0.0156 It1 )mo atmospheric lifetime using gas-phase reaction with OH radical = 0.8 to 2 daysq atmospheric lifetime using gas-phase reaction with OH radical = 1.1 to 2.4 daysq atmospheric lifetime using gas-phase reaction with OH radical = 1.5 to 3.4 daysq... 

Pulgarin, C. and J. Kiwi (1995). Iron oxide-mediated degradation, photodegradation, and biodegradation of aminophenols. Langmuir, 11(2), 519-526. 

In this chapter it has been shown that stabilisers can protect plastics from environmental damage. However, one solution to the problem of plastic litter is to utilise this chemical breakdown and make plastics degradable. Additives can be used to speed up the process rather than delay it. There are two key mechanisms which can be usefully harnessed for plastics degradation photodegradation and... 

Deterioration. The causes of degradation phenomena in textiles (155—158, 164) are many and include pollution, bleaches, acids, alkaUes, and, of course, wear. The single most important effect, however, is that of photodegradation. Both ceUulosic and proteinaceous fibers are highly photosensitive. The natural sensitivity of the fibers are enhanced by impurities, remainders of finishing processes, and mordants for dyes. Depolymerization and oxidation lead to decreased fiber strength and to embrittlement. 

In 1994, it is apparent that time has largely borne out these predictions. Where there has been no legislation the use of photodegradants appears to be diminishing. However, in at least one major industrial country legislation has taken place which will prevent use of non-degradable packaging films. 

The alternative approach is to add a photodegradant which is an ultraviolet light absorber. However, instead of dissipating the absorbed energy as heat (as with conventional ultraviolet absorbers) the aim is to generate highly reactive chemical intermediates which degrade the polymer. One such material is iron dithiocarbamate. 

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