scholarly journals Starch Solutions Prepared under Different Conditions as Modifiers of Chitosan/Poly(aspartic acid)-Based Hydrogels

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4443
Author(s):  
Magdalena Głąb ◽  
Anna Drabczyk ◽  
Sonia Kudłacik-Kramarczyk ◽  
Martin Duarte Guigou ◽  
Agnieszka Makara ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Aspartic Acid ◽  
Room Temperature ◽  
Volume Ratio ◽  
Starch Solution ◽  
Swelling Properties ◽  
Texture Analyzer ◽  
Hydrogel Matrix ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Recently, there has been great interest in the application of polysaccharides in the preparation of diverse biomaterials which result from their biocompatibility, biodegradability and biological activity. In this work, the investigations on chitosan/poly(aspartic acid)-based hydrogels modified with starch were described. Firstly, a series of hydrogel matrices was prepared and investigated to characterize their swelling properties, structure via FT-IR spectroscopy, elasticity and tensile strength using the Brookfield texture analyzer as well as their impact on simulated physiological liquids. Hydrogels consisting of chitosan and poly(aspartic acid) in a 2:1 volume ratio were elastic (9% elongation), did not degrade after 30-day incubation in simulated physiological liquids, exhibited a relative biocompatibility towards these liquids and similar swelling in each absorbed medium. This hydrogel matrix was modified with starch wherein two of its form were applied—a solution obtained at an elevated temperature and a suspension obtained at room temperature. Hydrogels modified with hot starch solution showed higher sorption that unmodified materials. This was probably due to the higher starch inclusion (i.e., a larger number of hydrophilic groups able to interact with the adsorbed liquid) when this polysaccharide was given in the form of a hot solution. Hydrogels modified with a cold starch suspension had visible heterogeneous inequalities on their surfaces and this modification led to the obtainment materials with unrepeatable structures which made the analysis of their properties difficult and may have led to misleading conclusions.

scholarly journals Synthesis of Propylene Oxide – Styrene Copolymers

2021 ◽  
Vol 10 (3) ◽  
pp. 2389-2395
Keyword(s):  
Propylene Oxide ◽  
Room Temperature ◽  
Structural Characteristics ◽  
Exchange Process ◽  
Proton Exchange ◽  
Styrene Copolymers ◽  
Forward Proton ◽  
Ft Ir ◽  
Ubbelohde Viscometer ◽  
Ft Ir Spectroscopy

The copolymerization of propylene oxide (PO) with styrene (St) catalyzed by Maghnite-H+ (Mag-H+) was investigated. Mag-H+, a nontoxic catalyst for cationic polymerization of vinylic and heterocyclic monomers, is a montmorillonite silicate sheet clay. This catalyst was prepared through a straight forward proton exchange process. It was found that Mag-H+ initiates the copolymerization in bulk at room temperature. Various techniques, including H1NMR, 13C-NMR, FT-IR spectroscopy, and Ubbelohde viscometer, were used to elucidate the resulting copolymers' structural characteristics. The effects of the amount of Mag-H+ and propylene oxide were studied. The yield of copolymerization depends on the amount of Mag-H+ used and the reaction time.

scholarly journals Congo Red and Nigrosine Dye Degradation using Dimethyl Dioxirane as an Oxidising Agent

2021 ◽  
Vol 37 (5) ◽  
pp. 1221-1228
Author(s):  
S. Vinotha ◽  
A.Leema Rose
Keyword(s):  
Congo Red ◽  
Room Temperature ◽  
Functional Group ◽  
Dye Degradation ◽  
Visible Spectroscopy ◽  
Before And After ◽  
Ft Ir ◽  
Combined Action ◽  
Uv Visible ◽  
Ft Ir Spectroscopy

The advanced oxidation of Congo red (CR) and Nigrosine (NI) using the combined action of dimethyl dioxirane as an oxidising agent is described in this study. The effects of several parameters, such as the concentration of the oxidising agent, the initial dye concentration, and the pH, have been investigated. At room temperature, the oxidising agent dimethyl dioxirane was employed to test the degradation of CR and NI dyes. On the degradation efficiency of CR and NI, pH’s effects, oxidising agent, and initial dye concentration were examined. The absorbance of CR and NI dyes before and after degradation was measured using UV-visible spectroscopy. The functional group existing in the dyes before and after degradation was determined using FT-IR spectroscopy.

Characteristics of carbon nanofibers produced from lignin/polyacrylonitrile (PAN)/kraft lignin-g-PAN copolymer blends electrospun nanofibers

Holzforschung ◽  
2017 ◽  
Vol 71 (9) ◽  
pp. 743-750 ◽  
Author(s):  
Chan-Woo Park ◽  
Won-Jae Youe ◽  
Song-Yi Han ◽  
Yong Sik Kim ◽  
Seung-Hwan Lee
Keyword(s):  
Tensile Strength ◽  
Fourier Transform ◽  
Carbon Nanofibers ◽  
Electrospun Nanofibers ◽  
Average Diameter ◽  
Kraft Lignin ◽  
Dimethyl Formamide ◽  
Copolymer Blends ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Abstract Lignin-based electrospun nanofibers (eNFs) were prepared and thermally stabilized at 250°C and subsequently carbonized at 1400°C. The starting blend was prepared in dimethyl formamide (DMF) solution with lignin and polyacrylonitrile (PAN), while a lignin-grafted-PAN (L-g-PAN) copolymer served as compatibilizer. The viscosity was highest of the DMF solution with PAN, and decreased for the lignin/PAN blends and additionally in presence of L-g-PAN. The uniform eNFs with clean surfaces dispose of diameters between 400 nm and 1 μm. The average diameter of eNFs decreased by the thermal treatment and at higher lignin contents in the blends. Remarkable shrinkage by carbonization was observed in all nanofibers. The successful carbonization of all electrospun carbon nanofibers (eCNFs) was confirmed by Fourier transform-infrared (FT-IR) spectroscopy. The specific tensile strength and elastic modulus of the eCNF mats from lignin/PAN blends were improved by the addition of L-g-PAN, and it can be safely concluded that it acts as a compatibilizer between lignin and PAN.

scholarly journals MODIFIED TEA LEAVES RESIDUAL FOR NICOTINE ADSORPTION

2021 ◽  
Vol 40 (3) ◽  
pp. 28-42
Author(s):  
Y. Walid AlBizreh ◽  
rasha Almostafa ◽  
Malak ALJoubbeh
Keyword(s):  
Experimental Data ◽  
Spectral Analysis ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Tea Leaves ◽  
Adsorption Models ◽  
Initial Concentration ◽  
Adsorbed Amount ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The boiled tea leaves residual was modified with oleum of weight 1:1 to prepare an adsorbent that is capable to adsorb nicotine on its surface. The surface properties of the sample were studied by using the FT-IR spectroscopy after each treatment resulting obvious peaks that indicate the modification of the sample with oleum and the adsorption of nicotine on its surface. The concentration of nicotine in the prepared solutions was measured by the use of spectral analysis. The change of nicotine΄s adsorption was studied with the change of time. An increase in the adsorbed amount was noticed until the equilibrium was reached after 24hours. In addition, an increase of the adsorbed amount of nicotine with the increase of its initial concentration was observed at the room temperature. The experimental data corresponded with adsorption models of Langmuir, Freundlish and Temkin, besides, a mechanism of the adsorption of nicotine was suggested to occur with the participation of the two nitrogen atoms.

scholarly journals Electrospun Nickel Manganite (NiMn2O4) Nanocrystalline Fibers for Humidity and Temperature Sensing

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4357
Author(s):  
Milena P. Dojcinovic ◽  
Zorka Z. Vasiljevic ◽  
Jugoslav B. Krstic ◽  
Jelena D. Vujancevic ◽  
Smilja Markovic ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Material Constant ◽  
Temperature Sensing ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
Bet Specific Surface Area ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Nickel manganite nanocrystalline fibers were obtained by electrospinning and subsequent calcination at 400 °C. As-spun fibers were characterized by TG/DTA, Scanning Electron Microscopy and FT-IR spectroscopy analysis. X-ray diffraction and FT-IR spectroscopy analysis confirmed the formation of nickel manganite with a cubic spinel structure, while N2 physisorption at 77 K enabled determination of the BET specific surface area as 25.3 m2/g and (BJH) mesopore volume as 21.5 m2/g. The material constant (B) of the nanocrystalline nickel manganite fibers applied by drop-casting on test interdigitated electrodes on alumina substrate, dried at room temperature, was determined as 4379 K in the 20–50 °C temperature range and a temperature sensitivity of −4.95%/K at room temperature (25 °C). The change of impedance with relative humidity was monitored at 25 and 50 °C for a relative humidity (RH) change of 40 to 90% in the 42 Hzπ1 MHz frequency range. At 100 Hz and 25 °C, the sensitivity of 327.36 ± 80.12 kΩ/%RH was determined, showing that nickel manganite obtained by electrospinning has potential as a multifunctional material for combined humidity and temperature sensing.

Preparation and Properties of PLA/Nano-ZnO Composite

2013 ◽  
Vol 392 ◽  
pp. 41-45 ◽  
Author(s):  
Li Bo Ding ◽  
Jiang Rui ◽  
Jun Tao Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fourier Transform ◽  
Silane Coupling Agent ◽  
Silane Coupling ◽  
Stretching Vibration ◽  
Ft Ir ◽  
Two Peaks ◽  
The Impact ◽  
Ft Ir Spectroscopy

In order to study the impact of nanoZnO on the mechanical properties of PLA, nanoZnO modified with different surface treatment agents (titanium ester NDZ-201,silane coupling agent KH550 ) was added to PLA matrix. The samples were examined by fourier transform infrared (FT-IR) spectroscopy, mechanical properties and SEM. The results show that infrared spectra of nanoZnO modified with different treatment agents include two peaks at 2852cm-1and 2925 cm-1, which are corresponding to C-H stretching vibration, peak at 1735cm-1which is corresponding to NH2, and peak at 964cm-1which is corresponding to P-O-Ti.when the addition of nanoZnO reaches to 1wt.%, the tensile strength of PLA/ZnO nanocomposites have the maximum values of 47.43MPa, increase to 9.64% by pure nanoZnO. The mechanical properties of PLA/ZnO nanocomposites can be improved modified with different treatment agents, and the dispersion of nanoZnO has been significantly improved.

scholarly journals Using Rutile TiO2Nanoparticles Reinforcing High Density Polyethylene Resin

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Vu Manh Tuan ◽  
Da Woon Jeong ◽  
Ho Joon Yoon ◽  
SangYong Kang ◽  
Nguyen Vu Giang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
High Density Polyethylene ◽  
High Density ◽  
Melt Blending ◽  
Ft Ir ◽  
Blending Process ◽  
Fesem Micrographs ◽  
Ft Ir Spectroscopy

The TiO2nanoparticles were used as a reinforcement to prepare nanocomposites with high density polyethylene (HDPE) by melt blending process. The original TiO2(ORT) was modified by 3-glycidoxypropyltrimethoxysilane (GPMS) to improve the dispersion into HDPE matrix. The FT-IR spectroscopy and FESEM micrographs of modified TiO2(GRT) demonstrated that GPMS successfully grafted with TiO2nanoparticles. The tensile test of HDPE/ORT and HDPE/GRT nanocomposites with various contents of dispersive particles indicated that the tensile strength and Young’s modulus of HDPE/GRT nanocomposites are superior to the values of original HDPE and HDPE/ORT nanocomposites. At 1 wt.% of GRT, the mechanical properties of nanocomposites were optimal. In DSC and TGA analyses, with the presence of GRT in the nanocomposites, the thermal stability significantly increased in comparison with pure HDPE and HDPE/ORT nanocomposites. The better dispersion of GRT in polymer matrix as shown in FESEM images demonstrated the higher mechanical properties of HDPE/GRT nanocomposites to HDPE/ORT nanocomposites.

The Optical Properties of Nitrogen Implanied Allminum Nitride Films

1988 ◽  
Vol 126 ◽  
Author(s):  
Takanobu Fujihana ◽  
Kenzo Kobayashi ◽  
Susumu Namba ◽  
Yisheng Dai ◽  
Masaya Iwaki
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Nitrogen Concentration ◽  
Optical Transmittance ◽  
Ir Absorption ◽  
Stoichiometric Ratio ◽  
Commercial Glass ◽  
N Dose ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Effects of N-implantation on the composition depth profile, the chemical bonds and the optical transmittance of AlNx films have been investigated by means of Auger Electron Spectroscopy (AES), Fourier Transform Infrared (FT-IR) spectroscopy and visible transmission spectroscopy. AINx films were deposited on silicon (111) and commercial glass by an Activated Reactive Eyaporation (ARE) technique near room temperature. The 40 and 80 keV N+ -implantations were carried out at room temperature with doses ranging from 5×1016 to 5×1017 ions/cm2. The result of AES measurements revealed that the as-deposited AlNx film on Si consists of the AIN layer near the topsurface and the Al-rich layer near the interface. The concentration of nitrogen in the films increases as the N-dose increases up to 1×1017 ions/cm2. The N-implantation at a dose of 5×1017 ion/cm2 causes the interface between the film and the Si substrate to mix rather than increase the nitrogen concentration in the film. This higher dose implantation makes the FT-IR absorption peak corresponding to Al-N bonding become clear, and it makes the optical transmittance at a wavelength of 4400 Å go from 7% for as-deposited AINx film up to 70–90%. It is concluded that N-implantation into AlNx films causes the formation of AIN with a stoichiometric ratio to improve optical properties of the film.

Study on Performances of Cyanethyl Chitosan Fiber Prepared from [Asp]Cl Ionic Liquid

2012 ◽  
Vol 581-582 ◽  
pp. 698-701
Author(s):  
De Zeng Xu ◽  
Ting Zhao ◽  
Zhi Chao Liu ◽  
Lu Nan Bai ◽  
Jing Guo
Keyword(s):  
Ionic Liquid ◽  
Aspartic Acid ◽  
Room Temperature ◽  
Breaking Strength ◽  
Fiber Strength ◽  
Bath Temperature ◽  
Wet Spinning ◽  
Ft Ir ◽  
Acid Hydrochloride ◽  
Chitosan Fiber

Aspartic acid hydrochloride ionic liquid ([Asp]Cl) was successfully synthesized from aspartic acid powder and 36% hydrochloric acid. The derivative of chitosan cyanoethyl chitosan was prepared by acrylonitrile and alkali chitosan at room temperature. Structures of ionic liquid and cyanoethyl chitosan were characterized by FT-IR. Crystalline properties of cyanoethyl chitosan were characterized by XRD. Cyanoethyl chitosan was dissolved in [Asp]Cl ionic liquid aqueous solution and subjected to wet spinning. The mechanical properties of cyanoethyl chitosan fibers were tested by type LLY-06 electronic single fiber strength tester, and the surface morphology of fibers were observed by microscope. The results show that the maximum breaking strength of fiber was 2.212CN/dtex when the concentration of cyanoethyl chitosan was 6.5% relativing to 3% ionic liquid and the coagulating bath temperature was 30°C.

Magnetite: Synthesis and Characterization

2013 ◽  
Vol 543 ◽  
pp. 460-463
Author(s):  
Christina Giannouli
Keyword(s):  
Room Temperature ◽  
Size Range ◽  
Precipitation Method ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Micro Emulsion ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Magnetite nanopowder is a nanostructured magnetic material which is of great importance due to its electric and magnetic properties at room temperature. There are quite enough methods to produce magnetite. In the present work, four samples of magnetite powder were produced, the first three with the alkaline precipitation method from aqueous solution of mixed Fe (II)/Fe (III) salts, without any surfactants and the last one with the micro emulsion method. The prepared powders have been characterized using transmission electron microscopy, Raman and FT-IR spectroscopy and x-ray diffraction in order the structure and the morphology of magnetite to be examined. The produced magnetite powders have a size range of 10-12±2nm and the chemical composition of magnetite.

Sign in / Sign up

Export Citation Format

Share Document