Morphological evolution of curauá fibers under acid hydrolysis

Abstract

Cellulose whiskers were obtained by means of sulfuric acid hydrolysis of curauá fibers. Before hydrolysis, the natural fibers were treated with an alkaline solution to remove the non-cellulosic content. Fiber degradation evolution and cellulose whisker formation were analyzed by structural and morphological analysis. The original fiber structure underwent a fragmentation mechanism after being exposed for 3 min to sulfuric acid. Cellulose whiskers were lixiviated from the fiber surface after 10 min of hydrolysis, developing two scenarios: one where the whiskers became unattached from the original fiber, and the other which remained attached. The cellulose whiskers presented a needle-like geometry with an approximate diameter of 11 nm and average length of 185 nm, after 30 min of acid hydrolysis. Based on microscopic characterization, a schematic representation of the morphological evolution of the cellulose fibers submitted to acid hydrolysis is proposed.

Morphological investigation of cellulose acetate/cellulose nanocrystal composites obtained by melt extrusion

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Isolation and characterization of cellulose nanowhiskers from Acacia caesia plant

“…Different chemical agents like sulfuric acid, hydrochloric acid, phosphoric acid, and so forth, are commonly used for the extraction of nanocellulose from natural fibers 36–40 . Among the various chemical methods, sulfuric acid hydrolysis is the most commonly used method for the extraction of cellulose from plant fibers.…”

Physicochemical, Mechanical and Morphologic Characterization of Purple Banana Fibers

“…However they are similar to those of other vegetable fibers whose values are 1.25 g/cm 3 , 1.03 g/cm 3 , 1.35 g/cm 3 , 1.45 g/cm 3 , 1.40 g/cm 3 and 1.35 g/cm 3 respectively for the coconut, palm, licuri, sisal and banana fiber 18,[20][21][22][23][24] . The low density of plant fibers is interesting for industrial because of the possibility of producing lighter weight materials, which is a key property for determining technological applications for natural fibers 6,25 . For the samples of banana fiber evaluated in this study, there was a small increase in the density of the fiber after the alkali treatment.…”