chemia - Studia

UV ABSORPTION PROPERTIES OF DOPED PVA TiO 2 MEMBRANES
EXPERIMENTAL SECTION
A PVA membrane with polymeric concentrations of 20% was employed,
in initial state and after addition of TiO 2 . The membrane was obtained by
mixing the polymer with distilled water, at constant temperature 25 0 C,
during several hours, until a homogeneous dispersion of polymer was obtained.
Then the gel was displayed on a glass plate and kept 24 hours in dark, at
room temperature, until the water evaporates. To obtain doped samples,
the TiO 2 was introduced in the polymeric gel in concentration 1%, 10% and
20%, mixed many hours, and then dried on open air [12]. These samples
were analyzed in their original state and after UV irradiation at different
intervals of time. The UV irradiation was performed with an VL 215 G lamp,
at 254 nm and 76 mW/cm 2 intensity. For all the samples the UV-vis spectra
were measured with a Jasco V-670 system with scan speed 200 nm/min, UV-vis
bandwidth 2 nm, and NIR bandwidth 8 nm. The Raman investigations were
performed with R 3000 CN systems, with excitation power 150 mW at
wavelength λ= 785 nm.
ACKNOWLEDGMENTS
This work was supported by CNCSIS-UEFISCDI, project PNII-
ID_PCCE_101/2008. Luciana Udrescu and Mihaela Pop acknowledge financial
support from a program co-financed by The SECTORAL OPERATIONAL
PROGRAMME HUMAN RESOURCES DEVELOPMENT, Contract POSDRU
6/1.5/S/3 – „Doctoral studies: through science towards society".
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