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Photodegradation of biodegradable PCL nanocomposites filled with TiO2 - nanotubes (TiNT)

The aim of this study is to evaluate the influence of TiO2 -nanotubes (TiNT) on the properties of biodegradable PCL nanocomposites before and after UV irradiation. The PCL/TiNT nanocomposites with a ratio of 1wt% TiO2 nanotubes were prepared by melt mixing using a laboratory Brabender mixer. The neat PCL and PCL/TiNT nanocomposites were irradiated for 120 and 240 hours using UV lamp. To characterize the thermal properties of PCL composites before and after UV irradiation the differential scanning calorimetry (DSC) were used. Thermal degradation and UV degradation was determined at heating rates of 5, 10, 15 and 20oC in a thermogravimetric analyzer in the temperature range from 25 to 600oC.Changes made on the characteristic functional groups after UV radiation were observed by FT-IR ATR spectroscopy. Activation energy (Ea) of fotodegradation for PCL and PCL/TiNT nanocomposites after UV degradation were determined by isoconversional methods Kissinger-Akahira-Sunose (KAS). The obtained results show that the glass transition temperature and melting temperature decreased when the samples are exposed to UV irradiation while the crystallization temperature and degree of crystallinity increased. The addition of fillers leads to an increase in thermal stability wich decreases by time of exposing the samples to UV irradiation. Based on the obtained results for Ea value after UV irradiation, all UV exposed samples, have lower Ea .

polycaprolactone (PCL); Ti-nanotubes; biodegradability; photodegradation; thermal stability; activation energy

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