T HE TARGET of this work is to choose a suitable nanoparticle for preparing a highly ultraviolet (UV)-shielding from poly (methylmethacrylate) (PMMA) nanocomposites at low concentration and to decrease the destructive effects of UV radiation. Morphologies of the synthesized nanoparticles were investigated by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM). Whereas, pure PMMA and its nanocomposites were characterized by using dynamic mechanical analysis (DMA), tensile testing, UV-visible spectra (T%), and thermogravimetric analysis (TGA). The obtained results showed a good correlation between the tensile properties, DMA and TGA analysis depending on the type of nanoparticles used in the PMMA matrix, especially in case of ZrO 2 and ZnO. Furthermore, UV-vis spectra were analyzed ranging from 200 nm to 800 nm. It showed that UV radiation is significantly blocked from 100% to 0.2 % in the UV range between 200 nm and 360 nm for pure PMMA and to 0.08 % for PMMA/CeO 2 nanocomposite and to 0.01 % for PMMA/ CeO 2 with various types of nanoparticles. After 360 nm, pure PMMA and PMMA/CeO 2 were a little bit affected by UV lights, whereas the PMMA based on different nanoparticles was not affected. This result demonstrates that these nanocomposites could be strongly candidates for the sunscreens or for several fields that related to the UV photodegradation effects.
Illumination using artificial light sources is common in these days. Many manufactures are paying for the design of lamps depending on high efficacy and low UV hazards. This research is focusing on the most useable lamps in the Egyptian markets; high pressure mercury (HPM), metal Halide (MH), and high pressure sodium (HPS). A set up for relative spectral power distribution based on single monochromator and UVA silicon detector for absolute irradiance measurements are used. The absolute irradiance in (W/m 2) in UVA region of the lamps and their accompanied standard uncertainty are evaluated.
T HIS paper summaries the evaluation of using two different nano-particles as UV blocking standard materials for treatment of hi-performance fabrics after UVB exposure. Six woven samples are manufactured using three different weave structure (Twill 2/2, Satin 5, and Weft backed structure), two different high tenacity weft yarn count and materials (polyester and polypropylene) are used. Titanium dioxide-Zinc oxide nano-particles are used as a treated materials to reduce the effect of UVB radiations, after that the samples were exposed to UVB breaking strength and tear strength are performed according to standard test methods to estimate the fabrics performance. The data are statistically analyzed and evaluated for the six samples using t-test for mechanical properties. Scanning electron microscope and ultraviolet protection factor (UPF) are done for samples before and after treatment. The results of Ultraviolet protection factor test shows that nano-titanium oxide material has a better coating treatment than nano-zinc oxide.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.