Kenaf bast nanocrystalline cellulose: Analysis of morphological, chemical, crystalline, and thermal

Abstract

Cellulose nanocrystals (CNC) were prepared from delignified kenaf bast fiber by using alkaline pulping, based on soda anthraquinone, hydrogen peroxide bleaching, and acid hydrolysis treatment with H2SO4. The size and morphology of the fibers were characterized by scanning electron microscopy (SEM), and the isolated fiber from unbleached and bleached pulp had a diameter between 9 to 30 µm. Fourier transform infrared (FTIR) spectroscopy exhibited that the content of lignin decreased in the pulping process, and the lignin was almost completely removed during hydrogen peroxide bleaching. Moreover, fibers were characterized for crystallinity using X-ray diffraction (XRD). The fiber crystallinity gradually increased at each stage of the process (raw kenaf bast, unbleached pulp, bleached pulp, and acid hydrolysis). The fiber was characterized by atomic force microscopy (AFM), which showed that the isolated pulp nanofibers had diameters of approximately 30 nm.