engleski

Non-isothermal decomposition kinetics of poly(ethylene oxide)/polyhedral oligomeric silsesquioxanes (PEO/POSS) nanocomposites

POSSs are nanoparticles composed of inorganic Si8O12 skeleton surrounded by eight organic groups. In this case the general formula is R7R'(SiO1.5)8 where R is isobutyl group and R' is phenyl group or monosupstituted phenyl group. The various POSS nanoparticles were prepared by corner capping reaction of isobutyltrisilanol with the suitable aryltrimethoxysilane. Substituents on phenyl group are methyl, metoxy, fluorine and chlorine. As non-volatile molecular nanoparticles, POSS can be incorporated in polymer matrix to modify specific property. In this work PEO nanocomposites with different hepta isobutyl polyhedral oligomeric silsesquioxanes (hib-POSS) were prepared by annealing method and the influence of hib-POSS type on the non-isothermal decomposition kinetics was investigated. The kinetic analysis of the non-isothermal data was performed using Netzsch Thermokinetics Professional software. The obtained results indicate that the non- isothermal decomposition of PEO is predominantly single-step reaction and therefore can be kinetically described by a single-step model. The non-isothermal decomposition process of all PEO/POSS samples is more complex compared to PEO and is kinetically described by a multi-step model. The kinetic parameters (activation energy, pre-exponential factor and reaction model/models) were calculated for PEO, each PEO/POSS sample and each decomposition step. POSS influences the beginning of the decomposition process while the main kinetic model for the characterization of PEO decomposition process remains the same in all samples.

poly(ethylene oxide), POSS, thermogravimetric analysis, kinetic analysis

nije evidentirano