Cell wall ultrastructure, anatomy, lignin distribution, and chemical composition of Malaysian cultivated kenaf fiber

The basic characteristics and physical properties of kenaf (Hibiscus cannabinus L.) fibers cultivated in the region of Penang, Malaysia were analyzed. For fundamental analysis, which includes nano-scale viewing for identification of kenaf cell wall ultra structure, fibers were viewed under transmission electron microscopy (TEM). Light microscopy (LM) was used to observe the physical characteristics, anatomy, and lignin distribution. Anatomical study was further carried out by scanning electron microscopy (SEM). Kenaf plants had a maximum height of 2.50 m, with a mean basal diameter of 1.74 cm. The wood (core) is the most abundant tissue with proportions up to 78% in cross-section area and up to 68.5% in weight. The mean dry density of stems was found to be 0.29 g/cm³, while that of core was 0.21 g/cm³ along the stems. A combination of LM and image analysis techniques was used to measure cell wall thickness and fiber length of the bast and core fibers. The fiber length of the bast was found to be longest (3637 μm) as compared to the core (1100 μm). Vessel members average 284 μm in length and 72 μm in diameter. The chemical composition was determined according to Technical Association of Pulp and Paper Industry (TAPPI) methods. Fourier transform infrared (FT-IR) spectroscopy was used to determine the functional groups present in the kenaf fiber samples.