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Jun 2023
Rifkatu Kambel DogaraCorresponding author
The increasing demand for environmentally-friendly materials has led to a surge in research on the production of biodegradable polymers. In this study, we investigate the synthesis of a biodegradable polymer by graft copolymerization of gum Arabic (GA) and polyethylene glycol (PEG). GA, a natural polysaccharide and PEG, a synthetic water-soluble polymer, were used as the backbone and graft monomer, respectively. The graft copolymerization was carried out using benzoyl peroxide as an initiator and performed under nitrogen atmosphere. The resulting polymer was characterized by Fourier transform infrared (FTIR) spectroscopy, Xray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The FTIR spectra confirmed the formation of the graft copolymer, and TGA analysis showed that the copolymer had higher thermal stability than GA. The DTA thermograms indicated two thermal events. The evaporation of water and organic polyethylene glycol components was measured, and the first mass loss was due to the loss of adsorbed and structural water in the gum Arabic, which occurred between 31.87 and 180°C, while the second, corresponding to the pyrolysis of polyethylene glycol functional groups and polysaccharide decomposition, resulted in a 70% mass loss. SEM morphological analysis of gum Arabic showed aggregates of high irregularity in particle shape. The cracks and holes obtained in the Gum Arabic micrograph disappeared from the new gum Arabic-graft-polyethylene glycol, leaving a smooth surface with scattered particles in the image, which was due to the grafting copolymer. From the XRD patterns, the percentages of the amorphous and crystalline phases were determined. The results show that gum Arabic has a 78% degree of crystallinity, whereas gum Arabic-graft-polyethylene glycol has the lowest value of 51%. Biodegradation activity was observed using the fungus Aspergillus flavus on different days on gum Arabic-g-polyethylene glycol. The results clearly showed inhibition zones with a change in the state of the copolymer from solid to liquid from days 8 to 14. These results indicate that the GA-PEG copolymer has potential as a biodegradable material for use in various applications, such as packaging, agriculture, and medical industries.
Apr 2023 DOI 10.14302/issn.2471-2140.jaa-22-4251
Kumari SachinCorresponding author
The study's goal was to determine the total phenolics, total flavonoids, and antioxidant activity of A. mexicana aerial parts. Extracts were prepared using different solvents namely n-hexane, ethyl acetate, acetone, methanol, and water on basis of increasing polarity using soxhlet appratus. Aqueous extract from the flower contained the highest level of total phenolics, followed by that of the stem and leaves. The flower methanol extract was found to contain the most total flavonoids. With IC50 values of 24.98 g/ml in acetone extract, the stem component demonstrated the most DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging activity, followed by leaves with IC50 values of 36.29 g/ml in hexane extract and flowers with IC50 values of 38.33 g/ml in acetone extract. FTIR analysis showed that the presence of phenols and flavanoids. In different solvents, the DPPH free radical scavenging activity of aerial portions of A. mexicana varied greatly, and it increased with increasing concentration levels. In terms of antioxidant potency, higher amounts of total phenolics in aqueous extract, total flavonoids in methanol extract, and acetone extract were shown to be the most potent antioxidant. The aerial parts of A. mexicana have a considerable amount of flavanoids, phenolics, and antioxidant activity.
Mar 2021 DOI 10.14302/issn.2377-2549.jndc-21-3738
Mahmoud M. S. AliCorresponding author
The present study aims to shed light directly towards the extraction of (IV) cerium ions using "liquid surfactant membrane" technology, "LSM" developed in the presence of synergistic cationic and nonionic materials. The effect of various factors such as Ce (IV) transport, synergistic surfactants, curing ratio, stir speed, temperature, and mixing time between the carrier and the cerium ion on the extraction rate was studied by LSM taking into account surfactant agents. The positive effect of benzethonium chloride "Hy-1622" on the extraction of cerium ion was demonstrated by LSMs technique. Experiments confirmed the efficiency of Hy-1622 chloride synergistically with Span 80/85 to extract cerium ions with LSMs technology for emulsions in the oil phase is critical as it determines the stability, viscosity and mass transfer resistance of the resulting emulsion. Besides, Hy-1622 chloride was found as a new cationic surfactant that appeared in FTIR characterization and surfactant was found to speed up the permeability process and accelerate the extraction rate due to electrostatic interaction with the carrier.
Dec 2017 DOI 10.14302/issn.2640-6403.jtrr-17-1840
Rogina AnamarijaCorresponding author
Faculty of Chemical Engineering and Technology, University of Zagreb
Up till now, chitosan has confirmed its versatile application in skin, cartilage and bone tissue engineering, as well as in drug delivery applications. This study is focused on enzymatic degradation of porous chitosan structures usually designed for mentioned purposes. In vitro degradation was monitored during four weeks of incubation at physiological temperature and in two different media, phosphate buffer saline solution and water. The scaffolds were characterised before and after enzymatic degradation using scanning electron microscopy and infrared spectroscopy with Fourier transformations (FTIR). According to the gravimetric analysis, higher weight loss of chitosan scaffolds was observed in buffered medium with respect to the water. The results implied that the total weight loss obtained in buffer involves physical dissolution of chitosan and lysozyme cleavage of glycoside bond. Importantly, FTIR identification of chitosan scaffolds after enzymatic degradation indicated the absence of lysozyme activity in water, indicating that weight loss is a result of the chitosan dissolution. This finding greatly impacts design of degradation experiments and characterisation of degradation behaviour of chitosan-based materials utilised as implants or drug delivery systems.
May 2017 DOI 10.14302/issn.2377-2549.jndc-17-1459
Saleem H.Corresponding author
Department of Physics, Annamalai University, Annamalainagar-608 002, Tamil Nadu, India
A combined experimental and theoretical study on molecular and vibrational structure of E-N¢ (ICINH) had been carried out. The FTIR, FT-Raman and UV-Vis spectra of ICINH were recorded in the solid phase. The optimized geometry was calculated by B3LYP method with 6-311++G(d,p) level of basis set. The harmonic vibrational frequencies, IR intensities and Raman scattering activities of the title compound were calculated at same level of theory. The scaled theoretical wavenumber showed very good agreement with the experimental values. The mulliken charges and thermodynamic functions of the ICINH were also performed at same level of theory. NLO and a study on the electronic properties such as excitation energies and wavelength, were performed by TD-DFT approach. HOMO–LUMO energy gap was also calculated and interpreted.
Apr 2017 DOI 10.14302/issn.2377-2549.jndc-17-1488
H.SaleemCorresponding author
Department of Physics, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India
The compound 2-(4-methoxyphenyl)-2, 3-dihydro-1H-perimidine (MPDP) was synthesized. The molecular structure and its functional groups were characterized with the help of Fourier Transform Infrared: FTIR/ Fourier Transform FT-Raman spectra in the regions of 400-4000/50-4000cm-1, respectively. The geometrical parameters, harmonic vibrational wavenumbers, Infrared (IR) & Raman scattering intensities, Nuclear Magnetic Resonance (NMR) chemical shift and Ultraviolet-Visible (UV-Vis) spectra were computed using B3LYP/6-311++G(d,p) level of theory. The complete vibrational analysis were made on the basis of Potential energy distribution (PED) calculation with the help of VEDA4 programme. The Highest occupied molecular orbital (HOMO) – Lowest unoccupied molecular orbital (LUMO) energy gap and intra-molecular charge transfer (ICT) were studied using NBO analysis. The first order hyperpolarizability (β0) and other related properties (β, α0, Δα) of MPDP were computed. The molecular electrostatic potential (MEP), Mulliken atomic charges were calculated using the same level of theory. In addition, the various thermodynamic parameters were also calculated.
May 2016 DOI 10.14302/issn.2377-2549.jndc-15-923
Wang FengqingCorresponding author
Key Laboratory of Pharmaceutical, College of Pharmaceutical Sciences, Hebei University, Baoding, 071000, P. R. China.
A hybrid monolithic column was prepared using octavinyloctasilasesquioxane (OVS) as a monomer, benzoyl peroxide/dimethylacetamide (BPO/DMA) as initiator, ethylene glycol dimethacrylate (EDMA) as cross-linker, 1-dodecanol as porogenic agent and dimethylbenzene as cosolvent. A tidy skeleton, much bigger specific surface area (22.4 m2/g) and lower swelling property of the monolithic column with OVS added than the one without OVS added were determined with Scanning Electron Microscopy (SEM), Nitrogen adsorption/desorption measurements (BET) and swelling test with elute of different concentration of acetonitrile in water. Fourier-transform infrared spectra (FTIR) was taken to characterize the composition of groups. Moreover, a better separation performance for benzene series compounds under reversed phase liquid chromatography (RPLC) mode was obtained using the monolithic columns with OVS added than those without.