Improvement of nanofibrillation efficiency of α-chitin in water by selecting acid used for surface cationisation

Abstract

Aqueous dispersions of partially deacetylated a-chitin (PDACh) were prepared using various organic and inorganic acids in water under various pH and ionic strength conditions. The degree of PDACh nanofibrillation in the dispersions was investigated by measuring their light transmittances, nanofibrillation yields, and zeta-potentials, and by atomic force microscopy observations. Highly transparent dispersions, consisting of mostly individualized PDACh nanofibrils (w = 3.4 ¡ 1.5 nm), were obtained when ascorbic acid and certain monovalent acids were used in water at pH 3.5. However, unfibrillated PDACh bundles were present in dispersions prepared with divalent and trivalent acids, probably because of formation of ionic cross-linkages between PDACh fibrils. When the acid concentration in the dispersions was adjusted to 0.04 M, those with higher dispersion pH exhibited higher nanofibrillation efficiency.Addition of excess acid inhibited efficient nanofibrillation of PDACh, owing to the high ionic strength that concomitantly occurred.

Nanostructured biocomposite films of high toughness based on native chitin nanofibers and chitosan

“…Again, the most likely reason is improved chitosan solubility and more favorable chitosan-chitosan mixing as well as more favorable chitosan conformations in the film. Chitin nanofiber colloidal properties also depend on molecular interactions (Qi et al, 2013 ) and this influences the degree of dispersion and the nanostructural details of the film. Poor dispersion in the collolid leads to agglomerate formation which may act as defects in the film so that the strain to failure is decreased.…”

Comparison of acidic deep eutectic solvents in production of chitin nanocrystals

“…Response: During the hydrolysis reaction of chitin the amorphous regions were dissolved firstly and then the crystalline regions. Previous study (Qi et al 2013) found that lactic acid is more active to the protonate chitin. Therefore, we deduced that lactic acid is more accessible to amorphous area of chitin in comparison to other acids.…”

“…Presumably, the hydrolysis reaction was suppressed because of the 178 esterification of the hydroxyl groups of chitin through formation of monoester or diesters (Sirviö 179 et al, 2016). The yield of ChNCs prepared through HCl hydrolysis is typically ranging from 40% 180 to 86% depending on reaction time and source of chitin (Araki et value among the used acids (Featherstone & Rodgers, 1981;Qi et al, 2013). The chitin with 243 diversity dimensions can potentially be applied in different areas.…”

Biopolymer nanofibrils: Structure, modeling, preparation, and applications

“…Partially deacetylated chitin was dispersed in water at acidic conditions by adding various organic and inorganic acids, and the effects of pH and ionic strength on the nanofibrillation efficiency of partially deacetylated chitin were described [240].…”