Thermoplastic polyurethane synthesis using POSS as a chain modifier

In this study, thermoplastic polyurethanes (TPUs) were synthesized using the one-shot process in solution. To obtain the samples n-phenylaminopropyl polyhedric oligomeric silsesquioxane (POSS) was added as a chain modifier during the synthesis in four different amounts. The samples were characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and capillary rheometry. FTIR confirm the TPU attainment due the absence of the band at ~2253 cm-1 suggesting a complete conversion of the isocyanate terminations. The TGA showed that incorporation of POSS decreased the rate of mass loss of TPU under isothermal conditions. The flexible phase showed an enhanced stability to temperature, probably due to increased phase separation between the rigid and flexible domains. The DSC showed that incorporation of 0.4 wt. (%) of POSS increased the glass transition temperature of the flexible phase. Moreover, addition of POSS modified the melting behaviour, providing samples with a higher melting enthalpy compared to neat TPU as a consequence of the formation of larger crystals. The capillary rheometry analysis revels that the POSS addition showed a clear tendency toward higher intrinsic viscosities as the amount of POSS was increased

Investigation of the Structure of the Biochar Obtained by Slow Pyrolysis of Elephant Grass during Its Steam Gasification

A detailed evaluation of the structure of biochar from slow pyrolysis of elephantgrass during its steam gasification was performed. The effects of surface area andinherent alkali and alkaline earth metal (AAEM) species on the reactivity of thebiochar were investigated. Drastic changes in biochar structure occurred through-out the reaction, especially for low degrees of conversion. The BET surface area ofthe biochar increased significantly until the conversion reached 0.49, and therewas a steep decrease at high degrees of conversion. The biochar showed a highAAEM concentration. The aromaticity of the biochar suggested an ordered car-bon structure that can lower the reaction rate. The high syngas yield makes theprocess attractive for generation of renewable energy

Investigation of the structure of the biochar obtained by slow pyrolysis of elephant grass during its steam gasification

A detailed evaluation of the structure of biochar from slow pyrolysis of elephantgrass during its steam gasification was performed. The effects of surface area andinherent alkali and alkaline earth metal (AAEM) species on the reactivity of thebiochar were investigated. Drastic changes in biochar structure occurred through-out the reaction, especially for low degrees of conversion. The BET surface area ofthe biochar increased significantly until the conversion reached 0.49, and therewas a steep decrease at high degrees of conversion. The biochar showed a highAAEM concentration. The aromaticity of the biochar suggested an ordered car-bon structure that can lower the reaction rate. The high syngas yield makes theprocess attractive for generation of renewable energy