Decomposition kinetics and lifetime estimation on natural fibre reinforced thermoplastic composites

Abstract

Through this study two different natural fibres composites were characterized from the point of view of decomposition kinetics comparing two kinetics models, Kissinger and Model Free Kinetics in order to estimate the lifetime of the composites. Composite materials were prepared with low density polyethylene as matrix and as reinforcements, plasma treated and untreated natural fibres with 20 and 30 wt.% of fibre content. Composites were manufactured using a rotor mixer and a hot plates press. Afterwards, thermogravimetric analysis was carried out for each material at six different rates with a coupled Mass Spectrometry device to identify detached elements in a specific temperature range. The influence of the low pressure plasma treatment, as well as the fibre type, was taken into account to evaluate the activation energy of the decomposition processes of each material. Besides, lifetime was estimated from the obtained decomposition energies and the Toop equation. It was found that plasma treatment does not have a meaningful influence on decomposition kinetics but, the main composition of the natural fibres is decisive in this aspect, giving rise to much longer lifetimes when the cellulose content of the fibre is higher.