Environmental Engineering Reference
In-Depth Information
(6.4)
where, Φ ( λ ) is the quantum efficiency of the degradation. The activation
spectrum, or the damage that is attributed to any waveband ( λ 1 < λ < λ 2 ), is
obtained by integrating the expression above over the wavelength interval.
With most plastics, however, the simple additivity implied by Equation 6.3
does not apply as there can be synergy or mutual cancellation of the effects
of different wavelengths.
The solar absorption cutoff and the most effective solar wavelength range
for selected modes of damage for different plastics based on reported
activation spectra are summarized in Table 6.1 . These data are for non-UV
stabilized plastics. The presence of a UV stabilizer or some additives in the
compound can change the activation spectra very significantly.
 
 
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