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The photodegradation behavior of poly(vinyl chloride) (PVC) nanocomposites containing different amounts of synthesized titanium dioxide (TiO 2 ) nanoparticles and commercial rutile powder is investigated via the formation of carbonyl compounds, peroxides, and polyenes propagation over 5112 h exposure, as a function of irradiation wavelength and intensity. All the PVC/TiO 2 nanocomposites are found to exhibit lower concentration of mentioned species compared with the composite samples. The results show that added TiO 2 nanoparticles can retard the photodegradation processes, wherein increasing the amounts of these nanoparticles yields more reduction. With an increase in irradiation intensity the rate of formation of investigated groups increases, although in cases with raised temperature range, this pattern is not observed. An evaluation on the irradiation wavelength effect also shows that more photon energy provides more degradation. The loss of weight analysis shows a tremendous and novel result on evaluating a point of meaningful weight loss.

In this study, nanocomposites of rigid poly(vinyl chloride) (UPVC) using the synthesized carbon-coated titanium dioxide (TiO 2 ) nanoparticles and commercial powder of titanium dioxide (with rutile structure) were prepared by melt blending. The presence of carbon-coated TiO 2 nanoparticles with rutile structure in UPVC matrix led to an improvement in photo stability of UPVC nanocomposites in comparison with commercial UPVC. The photocatalytic degradation behavior of nanocomposites was investigated by measuring their structural changes, surface tension, and mechanical and morphological properties before and after UV exposure for 700 h. It was found that mechanical and physical properties of UPVC nanocomposites are not considerably reduced after UV exposure in the presence of carbon-coated TiO 2 nanoparticles even in small percentage of nanoparticles in comparison with the presence of commercial TiO 2 particles. Therefore, it can be concluded that UPVC/TiO 2 nanocomposite with low content of carboncoated TiO 2 nanoparticles(0.25 wt %) illustrated high stability under light exposure.

As a first approach, this study presents a comprehensive experimental study of methanol steam reforming for hydrogen production using a tubular silica membrane reactor, in which the modified silica membrane was applied.