Isolation and Characterization of Cellulose Whiskers from Kenaf (<i>Hibiscus cannabinus</i> L.) Bast Fibers

Abstract

Cellulose whiskers were isolated from kenaf (Hibiscus cannabinus L.) bast fibers via sulfuric acid and hydrochloric acid hydrolysis. Raw kenaf bast, NaOH treated, bleached fibers, sulfuric acid whiskers (SAW) and hydrochloric acid whiskers (HClW) morphology, functional groups, crystallinity, and thermal stability were characterized. The TEM images showed that the sulfuric acid and HCl whiskers have average diameters and length range of 3 nm and 100 -500 nm, respectively. The FTIR study indicated that during the conversion process, most of the hemicellulose and almost all the lignin were removed by the NaOH and subsequent bleaching treatments. The crystallinity of HCl whiskers was found to be higher (84%) than that of sulfuric acid whiskers (72%). Thermogravimetric analysis indicated that HCl whiskers had better thermal stability than the sulfuric acid ones. In addition, a two-stage decomposition behavior was revealed by TGA in the sulfuric acid whiskers because of incorporation of the sulfate group with the cellulose crystals.

Effect of Preparation Conditions on Cellulose from Oil Palm Empty Fruit Bunch Fiber

“…Chemical treatment is the most effective way to obtain a higher purity cellulose. A combination of chlorite bleaching, alkali treatment, and acid hydrolysis is the most common process used to extract cellulose from the plants (Habibi et al 2010;Liu et al 2010;Rosa et al 2010;Siqueira et al 2010;Chen et al 2012;Kargarzadeh et al 2012;Sheltami et al 2012;Zaini et al 2013). Chlorite bleaching has the function of extracting holocellulose from raw cellulose fiber.…”

Effect of the chemical treatments on the characteristics of natural cellulose

“…Constant magnetic stirring combined with acid hydrolysis in H 2 SO 4 played a significant role in reducing fiber length and diameter. The fiber size resulted in this study was larger than that reported in [1,3] due to no mechanical treatments with a homogenizer [1] or a high frequency vibrator [3] were done.…”

“…The non-cellulosic components almost completely dissolved in 6% NaOH and led to homogeneous surface roughness and fibers with clean surface. The concentration of alkali used in this study was slightly higher than used previously [1,3]; the concentration of H 2 SO 4 was lower than in [1], but similar to that used in [3]. Constant magnetic stirring at 350 rpm was done during acid hydrolysis (H 2 SO 4 ).…”

“…Studies on isolation of cellulose from natural fibers have been done with various methods [1][2][3][4][5][6][7]. Alkali and bleaching treatments followed by acid hydrolysis have been used to extract cellulose nanowhiskers from the natural fibers [1,2].…”

“…Alkali and bleaching treatments followed by acid hydrolysis have been used to extract cellulose nanowhiskers from the natural fibers [1,2]. For example, Zaini et al [1] isolated cellulose from kenaf bast fibers by first applying four alkali and bleaching treatments followed by high concentration acid hydrolysis; this resulted in cellulose whiskers 100-500 nm in length and 5 nm in diameter. In a second study, cellulose nanofibers 50 nm in diameter were obtained by using biotreatment, refining and cryocrushing [7].…”