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Thermal degradation of PCL and PCL/micro and nano composites

In recent years, biodegradable polymers with controllable lifetime have become increasingly important for many applications in the areas of agriculture, biomedical implants and drug release, forestry, wild life conservation and waste management. Polycaprolactone (PCL) is one of an important group of thermoplastic materials and has recently received much attention because of its flexibility and biodegradability, applying in food packaging, tissue engineering, dressing for wound, and drug delivery. However, some shortcomings such as high cost, low melting temperature and low mechanical properties restrict widespread industrial use of PCL. In order to improve the physical properties of polymer, inorganic particles were usually used. Characterizing the thermal properties of such systems may be useful for the processing of the material and for the prediction of some features during their potential applications as biomaterials. This paper presents the thermal degradation behavior of PCL and its composites in different atmosphere (nitrogen, oxygen) by thermogravimetric analysis (TGA) under non-isothermal conditions. Composites based on a biodegradable PCL containing 0.5, 1.0 and 2.0 wt % of titanium dioxide (TiO2) micro and nanoparticles were prepared by melt mixing using a laboratory Brabender mixer. The TGA results indicate that the thermal stability of the PCL in the both atmosphere is improved by the presence of TiO2 microparticles compared to the TiO2 nanoparticles an neat PCL. PCL and its composites undergo completely different degradation processes in nitrogen and oxygen atmosphere. In oxygen atmosphere PCL mainly decompose to CO2, CO, water and short-chain acids, while in nitrogen atmosphere PCL releases 5-hexerioc acid, CO2, CO and -caprolactone.

polycaprolactone ; titanium dioxide ; composites ; thermal degradation ; thermogravimetric analysis

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