Proximate Chemical Analysis and Effect of Age and Height of Oxytenanthera abyssinica on Fiber Morphology and Chemical Compositions for Pulp and Paper Production Potential

Abstract

This study examined the chemical composition, fiber morphology, and physical properties of Oxytenanthera abyssinica culm to assess its pulping potential. Technical Association of the Pulp and Paper Industry (TAPPI) and Franklin’s methods have been used for experiments. The statistical analysis showed that the chemical composition of O. abyssinica is influenced by the age of the plant. The amount of cellulose in the culm increases with age, while hand extractive content decreases with age. The average chemical content of the three years aged O. abyssinica was $49.26\pm 0.13$  wt%, $21.31\pm 0.15$  wt%, and $20.63\pm 0.12$  wt% for cellulose, hemicellulose, and lignin contents, respectively. A significant difference exists between 1, 2, and 3-year aged plants ( $P<0.05$ ) in cellulose, lignin, ash, and extractive content. The position of the culm also affects the fiber morphology of O. abyssinica. The fiber’s length, diameter, cell wall thickness, and lumen diameter increase from top to bottom, whereas the flexibility and slenderness ratio decrease. The average fiber morphology of O. abyssinica was flexibility ratio ( $0.72\pm 0.10$ ), Runkel ratio ( $0.35\pm 0.10$ ), slenderness ratio ( $109.98\pm 0.21$ ), lumen diameter ( $15.63\pm 0.03$  μm), cell wall thickness ( $2.74\pm 0.03$  μm), fiber length ( $2.40\pm 0.10$  mm), and fiber diameter ( $21.83\pm 0.09$  μm). The above data showed that the mean value of the fiber length of the plant is greater than 1.5 mm, the Runkel ratio was less than 1, and the slenderness ratio was greater than 70 standard values. The result also showed that the average bulk density and the moisture content were 660 kg/m3 and 9.6%, respectively. Although O. abyssinica is widely grown in the study area, no comprehensive studies have been carried out on fiber morphology, chemical composition, and physical properties based on age and height. Thus, this research was carried out to study the plant’s fiber characteristics to assess its suitability for pulp and paper production. Based on the above data, the 3-year aged bottom part of O. abyssinica is recommended for more yield pulp and high-quality paper production than the first and second-year aged plant.