Authors
Abstract
The samples were cast as thin film from homopolymer (PMMA) before
and after doping with methyl orange at different concentration. The samples were
exposed to UV-radiation for exposure time within (10-50hr) range. These polymer
systems were evaluated spectrophotometrically for using the UV-detector. The
absorption spectra of UV-irradiated samples showed radiation induced absorption
changes in the wavelength range, which depends on the polymer type and polymer
composites. The increment depends dopant concentration, especially in ultra violet
region in exposed PMMA doped with methyl orange at 6.7×10-2wt/wt
concentration. Decreasing in absorption was found for the cases in which, photo
degradation caused surface damage, i.e. crazes or cracks formation, especially at
ultraviolet region. Calibration curves were drawn at peaks, selected wavelength in
the absorption spectra. The linear regions from the calibration curves were selected,
and dosimeter range was determined from the UV-irradiation sample response. It
was found that PMMA doped with methyl orange at 6.7×10 -2wt/wt concentration
can be use the UV-detector within range (10-40hr) at the wavelength of (300nm)
for its linear response at this range of irradiation.
Morphological investigations for the surface damages caused by thermal and photo
degradation are detected by optical microscope. It is found that the photo
degradation could easily lead to some mechanical surface degradation i. e (crazes
and cracks) formation.
Keywords
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