Investigation and application of different extraction techniques for the production of finer bamboo fibres

Bamboos are an important source of fibres. Natural bamboo fibres possess have characteristics that make them of potential use in textiles. However, they have not received the attention they deserve due to the difficulty of extracting finer fibres. Full utilization of the potential of bamboo requires the extraction of the fibres using advanced techniques. In this study, three different extraction methods were developed, utilizing a newly created composite enzyme and alkalis in combination to extract finer natural bamboo fibres. The new enzyme was applied in both a solid form and a liquid state. Mechanical processes were also employed in preparing the bamboo culms and extracting the fibres. Three commonly grown bamboo species, Bambusa emeiensis (Neosinocalamus affinis), Phyllostachys edulis (Phyllostachys heterocycla), and Phyllostachys reticulata (Phyllostachys bambusoides), were used in the study to extract natural bamboo fibres. The bamboo samples were treated with 3–6% alkali and 24–36% composite enzyme, based on their weight. The composite enzyme was a recently developed enzyme that was used in both a liquid form and a solid form without the need for water as a solvent (non-aqueous treatment). The physical properties such as moisture content, length and fineness, and mechanical (tensile) properties such as breaking tenacity, breaking load and breaking extension of the resulting fibres were assessed with their minimum, maximum and average values. Structural analyses were performed using infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal analyzer (TGA) and scanning electron microscopy (SEM). The yield percentages of bamboo fibres were also determined. The bamboo fibres had a moisture content of 7.32–7.71%, an average length of 5.48–6.01 cm, a linear density of 9.71–11.43 tex, a breaking load of 138.96–147.67 cN, a breaking tenacity of 12.16–15.21 cN/tex, and a breaking elongation of 2.60–2.75%. SEM, TGA and FTIR tests indicated that the fibres were not single cellulosic fibres but rather fibre bundles in which single fibres were bonded by lignin and hemicellulose. The TGA results showed that the fibres were sufficiently thermally stable to withstand high temperature textile processes. The XRD results indicated the improvement of the crystallinity of the natural bamboo fibres owing to the partial removal of the non-crystalline lignin and other components. The measured properties of the fibres showed standard deviation values of 0.36–2.52, indicating a high level of uniformity within each sample. The experimental results demonstrated that the fibres obtained in this study have the potential to be used in textiles. The fibre yield percentages (approximately 52.7–55.2%) confirmed that all three bamboo species have the potential to provide usable fibres.