Mechanical, Morphological, and Structural Characteristics of Caroa (Neoglaziovia variegata) Fibres

Abstract

The surface morphology, thermal behaviour and tensile mechanical properties of raw caroa (Neoglaziovia variegata) fibres have been characterised. The influence of fibre washing with flowing tap water on the surface morphology and thermal properties of these fibres has also been investigated. The results show that gummy tissues are attached to the surface of the raw fibres and that washing leads to the partial removal of these tissues and to the exposure of the inner fibrillar structure of the fibres. Thermogravimetric analysis indicates that fibre thermal degradation is characterised by three main degradation stages corresponding, respectively, to water release at low temperatures, followed by decomposition of hemicellulose and of α-cellulose. Fibre washing produces an increase in the fibre thermal degradation temperature, Tonset, and in the thermal decomposition rate. These characteristics are associated with the removal of gummy tissues and with a decrease in the compactness of the fibres respectively. The tensile properties obtained place caroa as a low-to-medium-strength fibre when compared with other lignocellulosic fibres, but with a strength level similar to that of coir fibres, which, nowadays, are used commercially on a fairly large scale.