Structural and physical characteristics of the yucca fiber

Yucca fiber is a natural cellulose fiber that can be extracted from the Yucca plant leaves by retting. The physical properties of the Yucca fiber are extremely sensitive to the retting conditions. This research was designed to study the effects of chemical retting on the structural and properties of this fiber. Chemical retting was done by soaking the Yucca leaf in 10 to 150 g/l sodium hydroxide concentration at 80 to 100 °C for 60 to 240 min. Fiber characteristics such as fineness, tenacity, functional groups, crystallinity, thermal degradation, and surface morphology were then investigated. The Yucca fibers exhibited high crystallinity (56–66%), high tenacity (36–46 cN/tex), and low linear density (3–5 tex). It was also found that the elementary fiber had a mean diameter of about 1.2 [Formula: see text] and a helical structure of square-shaped spires. The thermogravimetric analysis also indicated that the Yucca fiber had the thermal stability of up to 250 °C. Based on the findings, the Yucca fiber may be suitable for various applications such as a reinforcement material in the composites applications and can be turned to yarn for textile applications.

Linear Density and Surface Morphology of Kenaf Fibres from Different Extraction Methods

The fineness and morphology of kenaf fibres are the main focus of this paper. The kenaf fibres were processed through water retting, chemical retting and mechanical extractions. The water retting method produces finer fibres between 3.2 to 3.7 Tex while other methods produces fibres between 4.0 to 5.0 Tex. The chemical retting method resulted in smoother fibre surface when examined using Field Emission Scanning Electron Microscopy under different magnifications. The fibre diameters from the different retting and extraction methods vary from 33 to 134 m and did not show to have any relationship with fibre fineness.

The Influence of Different Retting Processes on the Strength of Fibres obtained from Poliostigma raticulatum, Grewia mollis, Cissus populnea and Hibiscus sabdariffa

<p class="1Body">The extraction of vegetable fibres from different parts of plants has been a major focal point in the search for natural fibres that would substitute synthetic fibres. Fibres from <em>Poliostigma reticulatum</em>, <em>Grewia mollis,</em> <em>Cissus populnea</em> and<em> Hibiscus sabdariffa</em> were extracted by water and chemical retting. In chemical retting different concentrations of NaOH and NH₄OH were used. The extracted fibres were further purified and their tensile strength measured. The pH of water was measured as retting progresses and observed to increase as the retting time increases. This was ascribed to the secretion of enzymes by microorganisms as they acted on the mucilaginous matter of the bast with the resultant loosening of the fibres. The tensile strength of the fibres was determined using the Shirley Testometric 220D and was observed to gradual decline as the retting time increases. This was attributed to the continual removal of non-fibrous matter and the freeing of the fibres in the composite. However, beyond the fifth week of retting, no appreciable change in tensile strength was observed. This suggested that most of the non-fibrous matter have been solublized and utilized as source of nutrients and energy by the microorganisms. Acidic metabolites were produced due to microbial activities may have changed the pH of the medium and subsequently hindered their growth. In chemical retting, as the concentration of the medium increases the strength of the fibres decreases to a minimum then remain constant. This was accredited to the breakdown of inter- molecular bonds between non-fibrous substances and the fibres. And subsequently, the non-fibrous components separate from the fibres and dissolved in the medium revealing the actual fibres strength. It was therefore, opined that retted fibres in water, 5% NH₄OH and 15% NaOH are clearer and lustrous for all sample except those from Kargo<em>.</em></p>