Effect of the chemical treatments on the characteristics of natural cellulose

Abstract

Abstract. In order to characterize the morphology and size distribution of the cellulose fibers, natural cellulose from kenaf bast fibers was extracted using two chemical treatments; (1) alkali-bleaching-ultrasonic treatment and (2) alkalibleaching-hydrolysis. Solutions of NaOH, H 2 O 2 and H 2 SO 4 were used for alkalization, bleaching and hydrolysis, respectively. The hydrolyzed fibers were centrifuged at a rotation speed of 10000 rpm for 10 min to separate the nanofibers from the microfibers. The separation was repeated in 7 steps by controlling pH of the solution in each step until neutrality was reached. Fourier transform infrared (FTIR) spectroscopy was performed on the fibers at the final step of each treatment: i.e. either ultrasonic treated-or hydrolyzed microfibers. Their FTIR spectra were compared with FTIR spectrum of a reference commercial α-cellulose. Changes in morphology and size distribution of the treated fibers were examined by scanning electron microscopy (SEM). FTIR spectra of ultrasonic treated-and hydrolyzed microfibers nearly coincided with the FTIR spectrum of commercial α-cellulose, suggesting successful extraction of cellulose. Ultrasonic treatment for 6 h resulted in a specific morphology in which cellulose nanofibers (≥100 nm) were distributed across the entire surface of cellulose microfibers ( 5 m). Constant magnetic stirring combined with acid hydrolysis resulted in an inhomogeneous size distribution of both cellulose rods (500 nm-3 m length, 100-200 nm diameter) and particles 100-200 nm in size. Changes in morphology of the cellulose fibers depended upon the stirring time; longer stirring time resulted in shorter fiber lengths.

Tensile Properties of Kenaf/E-glass Reinforced Hybrid Polypropylene (PP) Composites with Different Fiber Loading

“…3). The trend of formation of the kenaf fiber surface structure due to alkalization has also been reported [20]. But the structure is dependent upon the alkalization condition.…”

“…But the structure is dependent upon the alkalization condition. Cellulose microfibrils would separate from each other by the high concentration of alkali solution or hot alkalization [20].…”

In situ inorganic flame retardant modified hemp and its polypropylene composites

“…While the peak at 1235 cm À1 was the characteristic peak of C-O stretching of the aryl group in lignin. 25 These peaks indicated that lignin and hemicelluloses existed in the untreated ber specimens.…”