Structural differences between chitin polymorphs and their precipitates from solutions—evidence from CP-MAS 13C-NMR, FT-IR and FT-Raman spectroscopy

Focher, B.; Naggi, Annamaria; Torri, Giangiacomo; Cosani, A.; Terbojevich, M.

doi:10.1016/0144-8617(92)90101-u

Cited by 205 publications

(92 citation statements)

References 23 publications

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“…Both forms can be differentiated by infrared; solid-state NMR [80] spectroscopy, and X-ray diffraction [81][82][83]. A third allomorph, γ-chitin, has also been described [84].…”

Section: Structural Properties Of Chitinmentioning

confidence: 99%

Poriferan Chitin as a Versatile Template for Extreme Biomimetics

et al. 2015

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Abstract:In this mini-review, we shall first cover a short history of the discovery of chitin isolated from sponges; as well as its evolutionarily ancient roots. Next, we will delve into the unique structural, mechanical, and thermal properties of this naturally occurring polymer to illuminate how its physicochemical properties may find uses in diverse areas of the material sciences. We show how the unique properties and morphology of sponge chitin renders it quite useful for the new route of "Extreme Biomimetics"; where high temperatures and pressures allow a range of interesting bioinorganic composite materials to be made. These new biomaterials have electrical, chemical, and material properties that have applications in water filtration, medicine, catalysis, and biosensing. OPEN ACCESSPolymers 2015, 7 236

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“…Both forms can be differentiated by infrared; solid-state NMR [80] spectroscopy, and X-ray diffraction [81][82][83]. A third allomorph, γ-chitin, has also been described [84].…”

Section: Structural Properties Of Chitinmentioning

confidence: 99%

Poriferan Chitin as a Versatile Template for Extreme Biomimetics

et al. 2015

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“…For that, approximately 2 mg of sample was mixed with 98 mg of KBr previously oven dried, and the mixture homogenized in an agate mortar. The mixture was compressed in a hydraulic press to form a pellet of approximately 0.20 mm thick, which was then analyzed in triplicate (Focher et al, 1992).…”

Section: Characterizationmentioning

confidence: 99%

Alkali process for chitin extraction and chitosan production from Nile tilapia (Oreochromis niloticus) scales

Boarin-Alcalde

Fonseca

2016

lajar

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ABSTRACT. Chitosan is a biopolymer of wide application due to its characteristics and non-toxicity, presenting antimicrobial, antitumoral and cicatrizing activities. It is currently used as emulsifier, metal's chelating, edible biofilm and fat reducer. The variation in the deacetylation degree of this polymer gives differentiated functional properties. It is mainly obtained from crustaceans, but fish scales are also a potential source of this product, despite neglected so far. The aim of this study was to develop a method for chitin extraction and deacetylation for chitosan obtaining from Nile tilapia (Oreochromis niloticus) scales. Characterization showed that chitosan was completely purified. The chitin infrared spectrum presented a characteristic larger band in the region of 3,500 cm -1 , due to axial stretching vibrations of the OH group been completely purified, which disappeared in the chitin spectrum. However, a new band aroused at 1,640 cm -1 due to the NH2 deformation, which predominated over the band at 1,655 cm -1 , associated to the carbonyl (C=O) that tends to decrease, as the degree of deacetylation of chitosan increases. All bands observed were similar to those described in the literature. Although the yields were lower than the averages usually reported for crustaceans, they can be improved to obtain higher yields and deacetylation. Keywords: fish residue, chitin, chitosan, infrared, deacetylation, chemical processes.Proceso alcalino para la extracción de quitina y producción de quitosano a partir de escamas de tilapia del Nilo (Oreochromis niloticus)RESUMEN. El quitosano es un biopolímero de amplia aplicación debido a sus características y no toxicidad, presentando actividad antimicrobiana, antitumoral y cicatrizante. Actualmente se utiliza como emulsionante, quelante de metales, biopelícula comestible y reductor de grasas. La variación en el grado de desacetilación de este polímero ofrece diferentes propiedades funcionales. Se obtiene principalmente de crustáceos, pero las escamas de pescado también son una fuente potencial de este producto, proceso descuidado hasta ahora. El objetivo de este estudio fue desarrollar un método para la extracción de quitina y desacetilación de quitosano a partir de escamas de tilapia del Nilo (Oreochromis niloticus). Esta caracterización mostró que el quitosano fue completamente purificado. El espectro infrarrojo de la quitina presentó una ancha banda característica en la región de 3,500 cm -1, debido a vibraciones del estiramiento axial del grupo OH que ha sido completamente purificado, que desapareció en el espectro de la quitina. Sin embargo, se observó una nueva banda a 1,640 cm -1 causada por la deformación de NH2 que predominó sobre la banda de 1,655 cm -1 , asociada al carbonilo (C=O) que tiende a disminuir y al aumento del grado de desacetilación del quitosano. Todas las bandas observadas fueron similares a las descritas en la literatura. Aunque los rendimientos fueron menores que los promedios reportados generalmente para crustáceos, ellos se pueden mejo...

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“…Peak (3,263 cm -1 ) is generally assigned to the N-H stretching restricted by the intermolecular C(2)NH … O=C(7) H-bonds and peak (3,109 cm -1 ) to the O-H stretching restricted by the intermolecular C(6) OH … H-O-C (6 0 ) H-bonds [26,27]. In addition, the spectrum of the native chitosan is characterized by a splitting of the amide I vibration at 1,660 and 1,629 cm -1 which have been assigned to the stretching of C=O groups hydrogen bonded to N-H groups of the adjacent chain, and the stretching of the C=O groups bifurcated by forming an additional hydrogen bond to the primary OH groups of the same chain, respectively [28,29]. In contrast, evident differences can be observed when comparing the IR spectra of the regenerated chitosan from [Gly]Cl solvent (Fig.…”

Section: Resultsmentioning

confidence: 99%

Clean Preparation Process of Chitosan Oligomers in Gly Series Ionic Liquids Homogeneous System

Yuan

Liu

et al. 2011

J Polym Environ

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Chitosan oligomers because of its water solubility has some special physiological functions, such as binding lipid, affecting the mitogenic response, restraining the growth of tumors, and was widely used in cosmetics and health. H 2 O 2 /Gly (Glycine) series ionic liquids system, a new solvable-catalytic system, was an efficient clean process for preparation of chitosan oligomers. The effects of the anions of Gly series ionic liquids on the solubility and degradation for chitosan were investigated, and the results showed that [Gly]Cl aqueous solution was of good solubility and assistant degradation for chitosan. In additional, the mechanism for oxidative degradation of chitosan in ionic liquids (ILs) was studied. The effect on the property of chitosan oligomers catalyzed by H 2 O 2 , in two different kinds of solvents (HAc and [Gly]Cl) were compared. It was found that the performance of moisture absorption and retention of chitosan oligomers using ionic liquid aqueous solution as solvent was better than that using HAc aqueous solution as solvent, and even superior to that of hyaluronic acid. Furthermore, [Gly]Cl could be easily separated from the product and reused with only slight loss. It could provide an efficient and environmental friendly method for the preparation of chitosan oligomers in H 2 O 2 / ILs system.

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Structural differences between chitin polymorphs and their precipitates from solutions—evidence from CP-MAS 13C-NMR, FT-IR and FT-Raman spectroscopy

Cited by 205 publications

References 23 publications

Poriferan Chitin as a Versatile Template for Extreme Biomimetics

Poriferan Chitin as a Versatile Template for Extreme Biomimetics

Alkali process for chitin extraction and chitosan production from Nile tilapia (Oreochromis niloticus) scales

Clean Preparation Process of Chitosan Oligomers in Gly Series Ionic Liquids Homogeneous System

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