scholarly journals Preparation of Electrospun Polyvinyl Alcohol/Nanocellulose Composite Film and Evaluation of Its Biomedical Performance

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 223
Author(s):  
Xinbin Ji ◽  
Jing Guo ◽  
Fucheng Guan ◽  
Yuanfa Liu ◽  
Qiang Yang ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Raw Materials ◽  
Average Diameter ◽  
Hydroxyl Group ◽  
Microscopic Appearance ◽  
Artificial Blood ◽  
Maximum Value ◽  
Liquid Absorption ◽  
Free Hydroxyl ◽  
Nanofiber Membranes

Using polyvinyl alcohol (PVA) and nanocellulose (NC) as raw materials, PVA/NC nanofiber membranes were prepared by electrospinning. The hydrogen bonding, crystalline properties and microscopic appearance of PVA/NC membranes with different NC contents were characterized. The mechanical properties, liquid absorption and cytotoxicity of the nanofiber membrane were evaluated. The results show that the free hydroxyl group of the PVA/NC nanofiber membranes have a maximum value of 9% at a mass fraction of 6% NC. The crystallinity of the PVA/NC nanofiber membranes and the average diameter of the nanofibers decreased and then increased as the NC content increased, with a minimum value of 38.23% and 272.03 nm, respectively, at 6% NC content. At this time, the contact angle was the smallest. The maximum strength of the PVA/NC nanofiber membranes is 75.8% higher than that of the PVA membrane at 2% NC content. With increasing NC content, the absorption of water, PBS sustained-release suspensions and artificial blood by PVA/NC nanofiber membranes increases. Cytotoxicity tests have shown that PVA/NC nanofiber membranes are non-toxic, have good cytocompatibility and are expected to be used in the field of medical dressings.

scholarly journals Post-electrospinning crosslinking of guar/polyvinyl alcohol membrane

2016 ◽  
Vol 20 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Jingjing Shi ◽  
Enlong Yang
Keyword(s):  
Heat Treatment ◽  
Citric Acid ◽  
Polyvinyl Alcohol ◽  
Guar Gum ◽  
Weight Ratio ◽  
Average Diameter ◽  
Alcohol Solution ◽  
Electrospun Nanofiber ◽  
Ft Ir ◽  
Nanofiber Membranes

College of Material and Textile Engineering, Jiaxing University, Jiaxing, China The present study reports post-electrospinning crosslinking of guar/polyvinyl alcohol (PVA)/citric acid nanofiber membranes by heat treatment. Porous, interconnected nonwoven nanofiber membranes (average diameter 194?23 nm) were electrospun from a homogeneous blend of 1wt% guar gum and 8wt% polyvinyl alcohol solution (3:7 weight ratio) containing 5 wt% (by the total weight of the solution) citric acid. The electrospun nanofiber membranes were then cured at 140 oC for 2 h. The crosslinked nanofiber membranes were insoluble in water, while the non-crosslinked membranes dissolved instantaneously. FT-IR spectrum investigates that crosslinking of guar/PVA occurred through esterfication reaction during heat treatment.

scholarly journals Multi-Scale Minero-Chemical Analysis of Biomass Ashes: A Key to Evaluating Their Dangers vs. Benefits

2021 ◽  
Vol 13 (11) ◽  
pp. 6052
Author(s):  
Paola Comodi ◽  
Azzurra Zucchini ◽  
Umberto Susta ◽  
Costanza Cambi ◽  
Riccardo Vivani ◽  
...  
Keyword(s):  
Raw Materials ◽  
Average Diameter ◽  
Rietveld Analysis ◽  
Fly Ashes ◽  
Amorphous Content ◽  
Multi Scale ◽  
Italian Law ◽  
Polycyclic Aromatic ◽  
Mineralogical Study ◽  
The One

A multi-methodic analysis was performed on five samples of fly ashes coming from different biomasses. The aim of the study was to evaluate their possible re-use and their dangerousness to people and the environment. Optical granulometric analyses indicated that the average diameter of the studied fly ashes was around 20 µm, whereas only ~1 vol% had diameters lower that 2.5 µm. The chemical composition, investigated with electron probe microanalysis, indicated that all the samples had a composition in which Ca was prevalent, followed by Si and Al. Large contents of K and P were observed in some samples, whereas the amount of potentially toxic elements was always below the Italian law thresholds. Polycyclic aromatic hydrocarbons were completely absent in all the samples coming from combustion plants, whereas they were present in the fly ashes from the gasification center. Quantitative mineralogical content, determined by Rietveld analysis of X-ray powder diffraction data, indicated that all the samples had high amorphous content, likely enriched in Ca, and several K and P minerals, such as sylvite and apatite. The results obtained from the chemo-mineralogical study performed make it possible to point out that biomass fly ashes could be interesting materials (1) for amendments in clayey soils, as a substitution for lime, to stimulate pozzolanic reactions and improve their geotechnical properties, thus, on the one hand, avoiding the need to mine raw materials and, on the other hand, re-cycling waste; and (2) as agricultural fertilizers made by a new and ecological source of K and P.

scholarly journals Mining Wastes of an Albite Deposit as Raw Materials for Vitrified Mullite Ceramics

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 232
Author(s):  
Pedro J. Sánchez-Soto ◽  
Eduardo Garzón ◽  
Luis Pérez-Villarejo ◽  
George N. Angelopoulos ◽  
Dolores Eliche-Quesada
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Phase Evolution ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Mining Wastes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Value

In this work, an examination of mining wastes of an albite deposit in south Spain was carried out using X-ray Fluorescence (XRF), X-ray diffraction (XRD), particle size analysis, thermo-dilatometry and Differential Thermal Analysis (DTA) and Thermogravimetric (TG) analysis, followed by the determination of the main ceramic properties. The albite content in two selected samples was high (65–40 wt. %), accompanied by quartz (25–40 wt. %) and other minor minerals identified by XRD, mainly kaolinite, in agreement with the high content of silica and alumina determined by XRF. The content of Na2O was in the range 5.44–3.09 wt. %, being associated with albite. The iron content was very low (<0.75 wt. %). The kaolinite content in the waste was estimated from ~8 to 32 wt. %. The particle size analysis indicated values of 11–31 wt. % of particles <63 µm. The ceramic properties of fired samples (1000–1350 °C) showed progressive shrinkage by the thermal effect, with water absorption and open porosity almost at zero at 1200–1250 °C. At 1200 °C, the bulk density reached a maximum value of 2.38 g/cm3. An abrupt change in the phase evolution by XRD was found from 1150 to 1200 °C, with the disappearance of albite by melting in accordance with the predictions of the phase diagram SiO2-Al2O3-Na2O and the system albite-quartz. These fired materials contained as main crystalline phases quartz and mullite. Quartz was present in the raw samples and mullite was formed by decomposition of kaolinite. The observation of mullite forming needle-shape crystals was revealed by Scanning Electron Microscopy (SEM). The formation of fully densified and vitrified mullite materials by firing treatments was demonstrated.

scholarly journals Studies on the formation of complex oxidation and condensation products of phenols. Part III. -Rearrangements of oxidation-reduction type in the diquinone group

1933 ◽  
Vol 143 (848) ◽  
pp. 223-228 ◽  
Keyword(s):  
Hydroxyl Group ◽  
Hydrogen Atoms ◽  
Blue Colour ◽  
Highly Active ◽  
Oxidation Reduction ◽  
Intramolecular Reactions ◽  
Trimethyl Ether ◽  
Free Hydroxyl ◽  
Ethereal Oxygen ◽  
Complex Oxidation

The diquinones have been but little investigated, and as they contain two condensed highly active quinonid systems it is to be anticipated that they should be capable of interesting intramolecular reactions. When heated to 210-215º, 4 : 4'-dimethoxydiquinone is rapidly converted into a red crystalline isomeride (yield, 90%), soluble in alkali with an intense blue colour, and yielding a mono-acetate indicating the occurrence of a free hydroxyl group. Two hydrogen atoms are taken up on reduction, and the phenolic product yields a triacetate and a trimethyl ether. It follows that of the four carbonyl oxygens of 4 : 4'-dimethoxydiquinone, one has been converted into a hydroxyl group, and another which does not exhibit any functional activity, is probably present as ethereal oxygen. These results led to formula (III) as representing the product of rearrangement.

scholarly journals An Antimicrobial Peptide-Loaded Chitosan/Polyethylene Oxide Nanofibrous Membrane Fabricated by Electrospinning Technology

2021 ◽  
Vol 8 ◽  
Author(s):  
Ling Yu ◽  
Shubin Dou ◽  
Jinghan Ma ◽  
Qiang Gong ◽  
Mogen Zhang ◽  
...  
Keyword(s):  
Wound Healing ◽  
Polyethylene Oxide ◽  
Total Concentration ◽  
Average Diameter ◽  
Nanofiber Membrane ◽  
New Class ◽  
Intensity Changes ◽  
Good Biocompatibility ◽  
Nanofiber Membranes

Antimicrobial peptides (AMPs) are a new class of promising antibacterial agents. We prepared electrospinning chitosan (CS)-polyethylene oxide (PEO) nanofiber membranes containing different concentrations of an antibacterial peptide NP10. The average diameter of nanofibers increased with the total concentration of NP10. The FTIR shows that all the peaks of CS-PEO nanofiber membranes with different concentrations of NP10 were almost the same as those of pure CS-PEO nanofiber membranes, and only the peak intensity changes. Adding NP10 can improve the thermal stability of CS-PEO nanofiber membranes. In the in vitro release experiment, NP10 was released from the CS-PEO-0.5%NP10 nanofiber membrane in a burst first and then slowly and continuously. Simultaneously, the CS-PEO-NP10 nanofiber membrane had good antibacterial activity against Escherichia coli and Staphylococcus aureus and good biocompatibility. In animal wound healing experiments, CS-PEO-0.5%NP10 nanofiber membrane had advantages over gauze and CS-PEO nanofiber membrane in wound healing. These properties may provide a choice for the clinical application of AMPs and treatment of wound infections.

scholarly journals Synthesis of Acid Polyols As a Feedstock to Produce Flexible Polyurethanes and Their Effect on the Income Level of Furniture Craftsmen

2019 ◽  
Vol 2 (1) ◽  
pp. 39
Author(s):  
Andi Budirohmi
Keyword(s):  
Fourier Transform ◽  
Fatty Acid ◽  
Raw Materials ◽  
Raw Material ◽  
Polymerization Process ◽  
Hydroxyl Group ◽  
Infra Red ◽  
Renewable Raw Material ◽  
Shoe Soles ◽  
Alternative Feedstock

Polyuretanes are widely used as elastomers, coatings, adhesivesand binders,interior and exterior cars, furniture,shoe soles, carpets, rigit and flexible foams, membrane materials as well as constuction materials .The production of polyurethanes is largely derived  from  polyols derived from petroleum . Howover, petroleum  is a non- renewable raw material . Thus it is necessary to look alternative feedstock  for the manufacture of polyol  as a polyurethane raw material. Synnthesis polyurethane by polymerization process  using  polyol volume based on polyol  oleat acid  polypropylenglycol ( PPG ) in order to know  whether fatty acid can be used  as raw materials  of polyurethane manufacture.From the result of the study. Based on Fourier Transform Infra  Red ( FTIR), showed,that the product  produced is polyol with obtained hydroxyl  group ( OH group )with hydroxylnumber is 129,81 mg KOH / g and 157,60 mg KOH / g sample of 70 

scholarly journals Functional and technological properties and methods of introduction of grain raw materials in the manufacture of meat and vegetable products

2021 ◽  
Vol 32 ◽  
pp. 03008
Author(s):  
Oksana Evdokimova ◽  
Vladimir Masalov ◽  
Tamara Ivanova ◽  
Yoshaa Ibrahim
Keyword(s):  
Hydrothermal Treatment ◽  
Mathematical Description ◽  
Raw Materials ◽  
Soy Flour ◽  
Weak Effect ◽  
Technological Properties ◽  
Protein Balance ◽  
Steady Decrease ◽  
Maximum Value ◽  
Vegetable Products

Currently, it is possible to ensure the protein balance in food only when combining plant and animal proteins. The functional and technological properties and methods of introducing non-meat ingredients (meal and grain raw materials) in the production of meat and vegetable pates are investigated. The influence of the degree of grinding of cereals on the viscosity properties of flour that has undergone hydrothermal treatment is studied. А direct dependence of the maximum value of the loading force on the degree of grinding of cereals is established, with an increase in the degree of grinding of cereals, the strength characteristics increase. The water-retaining capacity (WRC) of flour proteins was studied, so deodorised non-fat soy flour has the least ability to bind water, with a hydromodule of 1:1.75, 6.1% of water is separated, with a hydromodule of 1:2.25, buckwheat groats did not bind only 6.6% of water. Flour from cereal oat flakes, separation of non-cohesive water (8.5%) with a hydromodule of 1:2.5, with an increase in the hydromodule to 1:3, there is a slight decrease in this indicator by 7.5%. The fat module has a weak effect on the FRC of the flour samples being studied. Flour from cereals has a lower FRC, with fat modules (1:0.5) FRC does not change significantly and is from 0.44 to 0.45 g of oil per 1 g of flour, and for deodorised non-fat soy flour it is 100%. The mathematical description of the process of absorption of water and fat by flour from cereals and soy flour showed a steady decrease in WRC and an increase in WRC with an increase in hydro-and fat modules.

scholarly journals Synthesis and Characterizations of Dipeptide Derivative of Gentamicin

2019 ◽  
Vol 28 (2) ◽  
pp. 73-82
Author(s):  
Oun D. Khudair ◽  
Diar A. Fatih
Keyword(s):  
Acid Chloride ◽  
Solution Method ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Free Hydroxyl ◽  
Ester Linkage ◽  
Amine Groups ◽  
Conventional Solution ◽  
Dipeptide Derivative

Abstract       The target derivative are gentamicin linked with L-Val- L-Ala by an ester linkage. These were synthesized by esterification method, which included the reaction of -OH hydroxyl group on (carbon No.5) of gentamicin with the acid chloride of the corresponding dipeptide, The preparation of new derivative of gentamicin involved protected the primary & secondary amine groups of Gentamicin, by Ethylchloroformate (ECF) to give N-carbomethoxy Gentamicin which was used for further chemical synthesis involving the free hydroxyl groups. Then prepared dipeptide (L-Val- L-Ala) by conventional solution method in present DCC & HoBt then reacted with thionyl chloride to prepared acid chloride of dipeptides, then after, linked by ester linkage to N-protection gentamicin in present pyridine as base, finally deportation the amino group of synthesized compound by using TFAA in present anisole. The characterization of the titled compounds were performed utilizing FTIR spectroscopy, CHNS elemental analysis, and by measurements of their physical properties.  

Borneol-Shellac Nanofiber Membranes Fabricated Using a Modified Coaxial Electrospinning

2014 ◽  
Vol 1058 ◽  
pp. 78-82 ◽  
Author(s):  
Deng Guang Yu ◽  
Ying Xu ◽  
Song Liu ◽  
Yu Hai Wang ◽  
Xiao Duan ◽  
...  
Keyword(s):  
Physical Stability ◽  
Amorphous State ◽  
Average Diameter ◽  
Electrospinning Process ◽  
Flow Rate Ratio ◽  
Coaxial Electrospinning ◽  
High Quality ◽  
Pure Ethanol ◽  
Sheath Fluid ◽  
Nanofiber Membranes

A modified coaxial electrospinning process is developed for producing medicated nanofiber membranes of shellac. With pure ethanol as a sheath fluid, high quality borneol-loaded shellac nanofibers have been successfully fabricated using the modified coaxial process. Electron scanning microscopic observations demonstrated that the nanofibers had better quality than those fabricated using a single fluid electrospinning in terms of nanofiber diameters and their distributions. The former had an average diameter of 570 ± 80 nm under a sheath-to-core flow rate ratio of 0.25, whereas the later was 940 ± 230 nm. X-ray diffraction results verified that borneol existed in the shellac matrix in an amorphous state. The medicated nanofiber membranes could significantly improved the physical stability of borneol due to the favorable hydrogen bonding between the drug and the polymer matrix, as demonstrated by the weight loss experiments. The modified coaxial electrospinning process described here expands the capability of electrospinning process in generating high quality functional membranes.

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