Extraction and characterization of lignocellulosic fiber from Prosopis Juliflora bark: Effects of retting method, fiber particle size and alkali treatment cycle on cellulosic properties

The need to substitute synthetic fiber from petroleum precursor with natural fiber is becoming a priority in combating environmental and economic challenges. In this study, lignocellulosic fiber was extracted from the bark of an invasive plant of Prosopis Juliflora (PJ) using a modified dry retting method. The fiber was then chopped into three sizes, followed by two successive alkali treatments. The effects were then examined for their cellulosic properties. X-ray diffraction (XRD) results revealed that second-cycle alkali-treated coarse fibers (2TC) exhibited cellulose type-I and a crystallinity index (CI) of about 77 %. Moreover, thermogravimetric analysis (TGA) showed onset degradation and cellulose decomposition temperatures of 255 °C and 379 °C, respectively, while its cellulose content was around 50 %. Furthermore, the tensile strength test of the fiber resulted in about 12.48 ± 1.59 cN/Tex with a maximum force of 3.68 ± 0.56 N and elongation at a break of 5.2 % ± 1.85. The Fourier transform infrared spectra (FT-IR), scanning electron microscope (SEM) micrographs, and energy dispersive spectroscopy (EDS) ensured the removal of amorphous components after treatments. As a result of their improved cellulose properties, doubly alkalized coarse fibers are suitable feedstock for reinforcing polymer composites.