Chitosan derivatives with thickening properties obtained by reductive alkylation

Alves, Keila dos Santos; Vidal, Rosangela Regia Lima; Balaban, Rosângela de Carvalho

doi:10.1016/j.msec.2008.11.008

Cited by 11 publications

(4 citation statements)

References 27 publications

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“…In acid solution, the amino groups present in the chitosan chain are protonated, limiting the interactions between macromolecules due to electrostatic repulsion [80]. At higher pH than the pKa of 6.3, chitosan’s amines become deprotonated, and favor the formation of hydrogen bonds between the hydroxyl groups and the amine groups of chitosan [81]. Thus, the polymer loses its charge and becomes insoluble with gel or film forming characteristics.…”

Section: Resultsmentioning

confidence: 99%

“…This is, possibly, due to the low pH value (2.6) obtained in the chitosan solution, due to the presence of a large number of protonated groups. In addition, an excess of residual H + , thus generating great electronic repulsion when in contact with the fluids, with consequences undesirable as the reduction of its structural stability in the presence of moisture, leading to the disintegration of its fibers [80,81].…”

Section: Resultsmentioning

confidence: 99%

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Chitosan/Essential Oils Formulations for Potential Use as Wound Dressing: Physical and Antimicrobial Properties

et al. 2019

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Film-forming emulsions and films, prepared by incorporating different concentrations of clove essential oil (CEO) and melaleuca essential oil (MEO) into chitosan (CS) were obtained and their properties were evaluated. Film-forming emulsions were characterized in terms of qualitative assessment, hydrogen potential and in vitro antibacterial activity, that was carried by the agar diffusion method, and the growth inhibition effects were tested on the Gram-positive microorganism of Staphylococcus aureus, Gram-negative microorganisms of Escherichia coli, and against isolated fungi such as Candida albicans. In order to study the impact of the incorporation of CEO and MEO into the CS matrix, the appearance and thickness of the films were evaluated. Furthermore, Fourier transform infrared spectroscopy (FTIR), contact angle measurements, a swelling test, scanning electron microscopy and a tensile test were carried out. Results showed that the film-forming emulsions had translucent aspect with cloudy milky appearance and showed antimicrobial properties. The CEO had the highest inhibition against the three strains studied. As regards the films’ properties, the coloration of the films was affected by the type and concentration of bioactive used. The chitosan/CEO films showed an intense yellowish coloration while the chitosan/MEO films presented a slightly yellowish coloration, but in general, all chitosan/EOs films presented good transparency in visible light besides flexibility, mechanical resistance when touched, smaller thicknesses than the dermis and higher wettability than chitosan films, in both distilled water and phosphate-buffered saline (PBS). The interactions between the chitosan and EOs were confirmed by. The chitosan/EOs films presented morphologies with rough appearance and with EOs droplets in varying shapes and sizes, well distributed along the surface of the films, and the tensile properties were compatible to be applied as wound dressings. These results revealed that the CEO and MEO have a good potential to be incorporated into chitosan to make films for wound-healing applications.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Chitosan/Essential Oils Formulations for Potential Use as Wound Dressing: Physical and Antimicrobial Properties

et al. 2019

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“…Figure exhibits the viscosity curves for HPAM, HPAM‐ g ‐PEOPPO1 and HPAM‐ g ‐PEOPPO2 in water at 25 °C (a) and 70 °C (b). All the polymer solutions have a shear thinning behavior, the viscosity decreases with increasing shear rate . In addition, the viscosity decreases with increasing temperature, due to the increased mobility of the macromolecules …”

Section: Resultsmentioning

confidence: 99%

HPAM‐g‐PEOPPO: Rheological modifiers in aqueous media of high temperature and high ionic strength

Lima

Marques

Villetti

et al. 2019

J of Applied Polymer Sci

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Partially hydrolyzed polyacrylamide (HPAM) is widely used as thickener in enhanced oil recovery (EOR), but the high temperature and salinity of oil reservoirs can reduce the viscosity and lead to polymer precipitation. To improve the performance of HPAM in high‐salinity and high‐temperature environments, the responsive amino‐terminated poly(ethylene oxide‐co‐propylene oxide) (PEOPPO) (EO/PO = 19/03) was grafted onto a HPAM backbone. The copolymers were prepared in water using 1‐ethyl‐3‐[3‐(dimethylamino)‐propyl]carbodiimide hydrochloride/N‐hydroxysuccinimide (EDC/NHS) as activators. Structural characterization was performed by 1H NMR and Fourier transform infrared (FTIR) and the responsive behavior was investigated by UV–Vis and rheology. Spectroscopic analyses confirmed that copolymers were successfully synthesized. UV–Vis showed that copolymers have combined salt and thermoresponsive character. Rheology in saline medium (ionic strength = 3.75 mol.L−1) revealed that, contrary to unmodified HPAM, HPAM‐g‐PEOPPO have thermothickening behavior and also higher viscosity than HPAM at 70 °C, suggesting the utilization of these copolymers as rheological modifiers under harsh conditions of temperature and salinity, such as the ones found in EOR applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47453.

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“…Typically, chitosan samples with a Mw of around 150-200 kDa are used to prepare N-akyl chitosan derivatives for rheological studies. do Santos et al have studied the rheological properties of alkylchitosan derivatives using a low Mw chitosan (35 kDa) [184]. A non-Newtonian behaviour due to the presence of hydrophobic groups was observed.…”

Section: Effect Of Physico-chemical Properties (Mw and Dd) On Chitosamentioning

confidence: 99%

Chitosan Amphiphilic Derivatives. Chemistry and Applications

Aranaz¹,

Harris²,

Heras³

2010

COC

263

144

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Chitosan is a natural polymer composed of randomly distributed-(1-4)-linked D-glucosamine (deacetylated unit) and Nacetyl-D-glucosamine (acetylated unit). It has been described as a non-toxic, biodegradable and biocompatible polymer with very interesting biological properties, such as permeation-enhancing and mucoadhesive properties, anticoagulant and antimicrobial activity and so on. Chitosan has been used in several areas such as biomedical, pharmaceutical and biotechnological fields as well as in the food industry. Recently, there has been a growing interest in the modification of chitosan to improve its solubility in physiological conditions, to introduce new applications or to improve chitosan biological properties. Research and development on a variety of amphiphilic copolymers containing hydrophobic and hydrophilic segments, have been very active due to their spontaneous self-assembly behaviour in aqueous media These smart transitions often lead to diverse functional compartment structures like micelles, vesicles and gels, which represent promising applications in the field of biotechnology and pharmaceutics. The aim of the present paper is to review the latest advances in the synthesis of chitosan amphiphilic derivatives with a special emphasis in their applications.

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Chitosan derivatives with thickening properties obtained by reductive alkylation

Cited by 11 publications

References 27 publications

Chitosan/Essential Oils Formulations for Potential Use as Wound Dressing: Physical and Antimicrobial Properties

Chitosan/Essential Oils Formulations for Potential Use as Wound Dressing: Physical and Antimicrobial Properties

HPAM‐g‐PEOPPO: Rheological modifiers in aqueous media of high temperature and high ionic strength

Chitosan Amphiphilic Derivatives. Chemistry and Applications

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