Rheology and Thermal Studies of Stearoyl Chitosan Varying the Degree of Substitution

Katugampola, Pushpika; Casson, Cherese Winstead

doi:10.9790/019x-04012229

Cited by 8 publications

(15 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, no remarkable changes in the values of transition temperatures of the exposed samples were detected while the amounts of heat of fusion decrease with increasing the exposure dose up to 29.03 x 10 -14 J/m 2 and then increased while still lower than the unexposed one. These observations indicate that variation in crystal structure was created which may cause reduction in the heat of fusion of the phase change and are in good agreement with the DTA results previously reported [23,29]. Figure 5 illustrates the TGA and DTG curves for chitosan powder before and after exposure to UV-ozone for different doses.…”

Section: Methodssupporting

confidence: 88%

“…The second process (degradation process) starting at about 210 o C represents the phase transition temperature in the melting transition region and shows exothermic peaks centered at approximately 307 o C before and after exposure of chitosan powder. This phase transition may be due to the relaxation of the chain segments in the amorphous portion and decomposition of chitosan [29]. Besides, differences in shape and area of the first transition endotherms and melting exotherms peaks after exposure dose up to 38.75 x 10 -14 J/m 2 were also observed.…”

Section: Methodsmentioning

confidence: 93%

“…It was noticed that, the DTA thermograms of all samples display two decomposition stages which indicate the existence of more than one decomposition process. The first stage, < 100 o C, represents the first order thermodynamic transition which may be due to evaporation of physisorbed water from the sample [29]. The endothermic peaks addressed at about 60 and 63 o C before and after exposure of chitosan powder were detected, respectively.…”

Section: Methodsmentioning

confidence: 98%

See 2 more Smart Citations

Structural, Thermal and Optical Modifications of Chitosan due to UV-Ozone Irradiation

Abdel-Zaher

El‐Bassyouni

Moselhey³

et al. 2018

Egypt. J. Chem.

View full text Add to dashboard Cite

T HE PRESENT work focused on modifying the chitosan structure which has noticeable places in advanced research. The effect of UV-ozone irradiation with different exposure doses (9.68 x 10-14 , 19.35 x 10-14 , 29.03 x 10-14 and 38.75 x 10-14 J/m 2) on the microstructural, thermal stability and optical properties of chitosan was studied. X-ray diffraction (XRD), selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), optical parameters techniques as well as differential thermal analysis (DTA) and thermogravimetric analysis (TGA and DTG), were performed. The obtained results indicated that, effects on semi-crystalline structures have occurred. Detected variations in XRD, SAED, HRTEM, DTA and TGA analyses under investigation may be attributed to the different degrees of crystallinity, induction of structural changes and molecular configuration of chitosan upon exposure to UV-ozone. The results confirmed that the UV-ozone irradiation plays a role in refining the microstructure and changes occurring in chitosan matrix for future biomedical applications.

show abstract

Section: Methodssupporting

confidence: 88%

Section: Methodsmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 98%

See 1 more Smart Citation

Structural, Thermal and Optical Modifications of Chitosan due to UV-Ozone Irradiation

Abdel-Zaher

El‐Bassyouni

Moselhey³

et al. 2018

Egypt. J. Chem.

View full text Add to dashboard Cite

show abstract

“…Solubility studies were conducted to find suitable solvents to dissolve stearoyl chitosan compounds with high viscosity, which can be used in various applications. In this study, stearoyl chitosan with DS 86% was tried to dissolve in the concentration of 2% (w/v) in a series of solvents such as isopropanol, trifluoroacetic acid, dichloromethane, dimethylformamide, hexane, toluene, tetrahydrofuran, acetone, chloroform, pyridine, dimethylsulfoxide, trifluoroethanol, dimethylacetamide, and hexafluoroacetone sesquihydrate by sonicating for seven hours [2,[17][18][19][20].…”

Section: Solubility Studiesmentioning

confidence: 99%

“…Due to its non-toxicity, biodegradability, biocompatibility, low immunogenicity, antimicrobial activity, physiochemical, and biological properties, it can be used in various fields. But the poor solubility in water and most common organic solvents limits its applications [1,2].…”

Section: Introductionmentioning

confidence: 99%

Rheology and Thermal Studies of Stearoyl Chitosan Varying the Degree of Substitution

Katugampola¹,

Casson²

2017

IOSR JPTE

Self Cite

View full text Add to dashboard Cite

Two compounds of stearoyl chitosan; degree of substitution (DS) 79% and DS 86%, were synthesized by using the starting material as chitosan and deacetylated chitosan respectively. Fourier transform infrared (FT-IR) and Nuclear Magnetic Resonance (1 H NMR) spectroscopy were used to confirm the chemical structure of prepared products. The thermal stability of stearoyl chitosan decreased with increased DS while the DO (degree of order) increased with increased DS. The 2% (w/v) stearoyl chitosan (DS 86%) solutions displayed shear thinning behavior. Also, the shear stress and viscosity values were higher for stearoyl chitosan dissolved in pyridine than in toluene at the same shear rate. Since 2% stearoyl chitosan dissolved in pyridine had high viscosity with shear thinning property, it can be suitable as rheology modifiers.

show abstract

Chemical and biological characterization of sulfated chitosan oligomer as heparin mimics

Kocabay

Bahar

Tekin

et al. 2021

Polymers and Polymer Composites

View full text Add to dashboard Cite

In the present study, chitosan oligomer was modified to sulfated chitosan oligomer (ShCsO) to mimic heparin. Its chemical structure was determined by infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis. The results showed that the FT-IR spectrum band at 799 cm−1 corresponds to C–O–S and that at 1212 cm−1 corresponds to S=O bond stretching, which prove that the sulfate groups are incorporated into chitosan oligomer successfully. The antimicrobial activity of ShCsO against to Bacillus subtilis in 1% concentration was 89.1 ± 1.7% . The IC50 (μg/ml) of ShCsO was 67.75, 56.07, 85.47, and 84.68 for A2780, MCF-7, DU-145, and HepG2, respectively. The results show that this newly synthesized material is a potential candidate to heparin-like chitosan derivatives. According to the literature, it was the first time that chitosan oligomer was modified to mimic heparin.

show abstract

Rheology and Thermal Studies of Stearoyl Chitosan Varying the Degree of Substitution

Cited by 8 publications

References 12 publications

Structural, Thermal and Optical Modifications of Chitosan due to UV-Ozone Irradiation

Structural, Thermal and Optical Modifications of Chitosan due to UV-Ozone Irradiation

Rheology and Thermal Studies of Stearoyl Chitosan Varying the Degree of Substitution

Chemical and biological characterization of sulfated chitosan oligomer as heparin mimics

Contact Info

Product

Resources

About