scholarly journals Optimum Preparation Conditions for Highly Individualized Chitin Nanofibers Using Ultrasonic Generator

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2501
Author(s):  
Dagmawi Abebe Zewude ◽  
Hironori Izawa ◽  
Shinsuke Ifuku
Keyword(s):  
Sodium Hydroxide ◽  
Osmotic Pressure ◽  
Pressure Effect ◽  
Ultrasonic Energy ◽  
High Yield ◽  
Electrostatic Repulsion ◽  
Optimum Conditions ◽  
Preparation Conditions ◽  
Deacetylation Degree ◽  
Chitin Nanofibers

α-Chitin derived from crab shells was treated with 30% sodium hydroxide to prepare partially deacetylated chitin with a deacetylation degree of 36%. Partially deacetylated chitin nanofibers were prepared by applying weak ultrasonic energy generated by a domestic ultrasonic cleaner. The deacetylated chitin was easily disintegrated into nanofibers with the aid of electrostatic repulsion and osmotic pressure effect of amino cations on the chitin surfaces. The nanofibers were characterized in terms of yield, morphology, crystallinity, viscosity, and dispersibility. After a series of characterizations, ultrasonication with 45 kHz frequency and 20 min treatment was found to be the optimum conditions for obtaining fine nanofibers with a high yield.

scholarly journals Preparation and Sustained-Release Performance of PLGA Microcapsule Carrier System

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1758
Author(s):  
Shuaikai Ren ◽  
Chunxin Wang ◽  
Liang Guo ◽  
Congcong Xu ◽  
Yan Wang ◽  
...  
Keyword(s):  
Controlled Release ◽  
Biomedical Applications ◽  
Encapsulation Efficiency ◽  
Drug Carriers ◽  
Optimum Conditions ◽  
Carrier System ◽  
Preparation Conditions ◽  
Encapsulation Rate ◽  
Release Drug ◽  
Release Curve

Microcapsules have been widely studied owing to their biocompatibility and potential for application in various areas, particularly drug delivery. However, the size of microcapsules is difficult to control, and the size distribution is very broad via various encapsulation techniques. Therefore, it is necessary to obtain microcapsules with uniform and tailored size for the construction of controlled-release drug carriers. In this study, emulsification and solvent evaporation methods were used to prepare a variety of ovalbumin-loaded poly (lactic-co-glycolic acid) (PLGA) microcapsules to determine the optimal preparation conditions. The particle size of the PLGA microcapsules prepared using the optimum conditions was approximately 200 nm, which showed good dispersibility with an ovalbumin encapsulation rate of more than 60%. In addition, porous microcapsules with different pore sizes were prepared by adding a varying amount of porogen bovine serum albumin (BSA) to the internal water phase. The release curve showed that the rate of protein release from the microcapsules could be controlled by adjusting the pore size. These findings demonstrated that we could tailor the morphology and structure of microcapsules by regulating the preparation conditions, thus controlling the encapsulation efficiency and the release performance of the microcapsule carrier system. We envision that this controlled-release novel microcapsule carrier system shows great potential for biomedical applications.

scholarly journals Effect of hydrothermal pretreatment of corn stover with pH adjustment on properties of pulp and hydrolysate

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6826-6839
Author(s):  
Junjun Kong ◽  
Ling Zhang ◽  
Ziyi Niu ◽  
Rina Wu ◽  
Gaosheng Wang
Keyword(s):  
Sodium Hydroxide ◽  
Corn Stover ◽  
Ph Value ◽  
Major Product ◽  
Hydrothermal Pretreatment ◽  
Raw Material ◽  
High Yield ◽  
Pulp Yield ◽  
Industrial Utilization ◽  
The Relationship

In view of environmental and economic issues, co-production technology with pulp as the major product is an important developmental direction in biorefinery. In this paper, high-yield pulp was prepared by hydrothermal pretreatment with controlled pH and subsequent mechanical refining using corn stover as raw material. By adding acetic acid or sodium hydroxide, the properties of the hydrolysate and the pulp were altered. Reducing the pH during hydrothermal pretreatment resulted in more cellulose and hemicellulose being released, while less lignin was released. Increased pH led to more lignin being released, while dissolution of carbohydrates did not change significantly. A maximum pulp yield at pH 5.84 of hydrolysate was obtained when 3.0% sodium hydroxide was used. The strength of pulp is highly related to the removal of lignin during hydrothermal pretreatment. The relationship between pH value in hydrothermal pretreatment and the physical properties of the pulp was established and could be further used for prediction and as guidance for process control. Moreover, the results could be used to develop technologies for industrial utilization of agricultural straw to co-generate fiber and other bio-based products.

scholarly journals Effect of Hot Isostatic Pressing on Porosity and Mechanical Properties of 316 L Stainless Steel Prepared by the Selective Laser Melting Method

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4377
Author(s):  
Tomas Cegan ◽  
Marek Pagac ◽  
Jan Jurica ◽  
Katerina Skotnicova ◽  
Jiri Hajnys ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Hot Isostatic Pressing ◽  
Microstructural Analysis ◽  
Scanning Speed ◽  
High Yield ◽  
Laser Method ◽  
Preparation Conditions ◽  
Lower Porosity ◽  
316 L Stainless Steel

The manufacturing route primarily determines the properties of materials prepared by additive manufacturing methods. In this work, the microstructural features and mechanical properties of 316 L stainless steel prepared by the selective laser method have been determined. Three types of samples, (i) selective laser melted (SLM), (ii) selective laser melted and hot isostatic pressed (HIP) and (iii) selective laser melted and heat treated (HT), were characterized. Microstructural analysis revealed that SLM samples were formed by melt pool boundaries with fine cellular–dendritic-type microstructure. This type of microstructure disappeared after HT or HIP and material were formed by larger grains and sharply defined grain boundaries. The SLM-prepared samples contained different levels of porosity depending on the preparation conditions. The open interconnected LOF (lack of fusion) pores were observed in the samples, which were prepared with using of scanning speed 1200 mm/s. The blowhole and keyhole type of porosity were observed in the samples prepared by lower scanning speeds. The HIP caused a significant decrease in internal closed porosity to 0.1%, and a higher pressure of 190 MPa was more effective than the usually used pressure of 140 MPa, but for samples with open porosity, HIP was not effective. The relatively high yield strength of 570 MPa, tensile strength of 650 MPa and low ductility of 30–34% were determined for SLM samples with the lower porosity content than 1.3%. The samples after HIP showed lower yield strengths than after SLM (from 290 to 325 MPa) and relatively high ductility of 47.8–48.5%, regardless of the used SLM conditions.

scholarly journals Optimization of Activated Carbons Prepared byH3PO4and Steam Activation of Oil Palm Shells

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Daouda Kouotou ◽  
Horace Ngomo Manga ◽  
Abdelaziz Baçaoui ◽  
Abdelrani Yaacoubi ◽  
Joseph Ketcha Mbadcam
Keyword(s):  
Activated Carbon ◽  
Oil Palm ◽  
Activated Carbons ◽  
Optimum Conditions ◽  
Steam Activation ◽  
Experimental Conditions ◽  
Activation Temperature ◽  
Impregnation Ratio ◽  
Preparation Conditions ◽  
Two Factors

In this study, activated carbons were prepared from oil palm shells by physicochemical activation. The methodology of experimental design was used to optimize the preparation conditions. The influences of the impregnation ratio (0.6–3.4) and the activation temperature between 601°C and 799°C on the following three responses: activated carbon yield (R/AC-H3PO4), the iodine adsorption (I2/AC-H3PO4), and the methylene blue adsorption (MB/AC-H3PO4) results were investigated using analysis of variance (ANOVA) to identify the significant parameters. Under the experimental conditions investigated, the activation temperature of 770°C and impregnation ratio of 2/1 leading to the R/AC-H3PO4of 52.10%, theI2/AC-H3PO4of 697.86 mg/g, and the MB/AC-H3PO4of 346.25 mg/g were found to be optimum conditions for producing activated carbon with well compromise of desirability. The two factors had both synergetic and antagonistic effects on the three responses studied. The micrographs of activated carbons examined with scanning electron microscopy revealed that the activated carbons were found to be mainly microporous and mesoporous.

PEMBUATAN ZAT WARNA ALAMI DARI BIJI KESUMBA DALAM BENTUK KONSENTRAT TINGGI UNTUK PEWARNA MAKANAN

EKUILIBIUM ◽  
2014 ◽  
Vol 13 (2) ◽  
Author(s):  
Paryanto Paryanto
Keyword(s):  
Sodium Hydroxide ◽  
Water Content ◽  
Negative Impact ◽  
Extraction Process ◽  
Solvent Ratio ◽  
Synthetic Dyes ◽  
Bixa Orellana ◽  
Optimum Conditions ◽  
Natural Pigments ◽  
Maximum Absorbance

<p>Abstract: The use of synthetic dyes for food in Indonesia reached 88%. The synthetic dyes<br />have the negative impact for healthy. This study was conducted to determine how produce bixin<br />natural pigments from annatto seed by extraction process, how the optimum conditions and<br />their application. Bixin extraction from the seeds annatto using acetone (CH<br />3<br />) and<br />sodium hydroxide (NaOH) as solvent. The various of extraction were concentration, extraction<br />temperature, stirring speed and the ratio of material to solvent. The bixin analysis used UV-Vis<br />spectrophotometer at maximum absorbance and FTIR spectrophotometer to determine the<br />groups of bixin. The water content in the bixin seeds is 37%. The optimum conditions of the<br />extraction process of bixin seed is 0.25 N NaOH as solvent, 60<br />C, 400 rpm stirring speed and<br />weight of material to solvent ratio 1:20.<br />Keywords: Extraction, bixin, annatto, bixa orellana, sodium hydroxide<br />o<br />COCH<br />3</p>

Monomethyl β-Methylglutarate of New Synthetic Methods

2014 ◽  
Vol 960-961 ◽  
pp. 134-137
Author(s):  
Feng Wei He ◽  
Tong Liu ◽  
Ya Qin Zhang
Keyword(s):  
Sodium Hydroxide ◽  
Ethyl Ester ◽  
Acid Ester ◽  
Glutaric Acid ◽  
Addition Reaction ◽  
Tricarboxylic Acid ◽  
Synthetic Methods ◽  
High Yield

Malonate ethyl ester of butene in the presence of sodium hydroxide was synthesized by addition reaction of 2-methyl propane-1,1,3 tricarboxylic acid ester, by hydrolysis decarboxylation heatingβ-methyl glutaric acid. First with excess of methanol into methyl metaplasiaβ-methyl dimethyl glutarate, and then itsβ-methyl glutaric acid methylation, get high yield of monomethyl β-methylglutarate.

THE INFLUENCE OF MEMBRANE PREPARATION ON THE OSMOTIC PRESSURE OF POLYVINYL ACETATE IN ACETONE

1946 ◽  
Vol 24b (4) ◽  
pp. 150-166 ◽  
Author(s):  
R. E. Robertson ◽  
R. McIntosh ◽  
W. E. Grummitt
Keyword(s):  
Sodium Hydroxide ◽  
Osmotic Pressure ◽  
Cell Volume ◽  
Polyvinyl Acetate ◽  
Membrane Surface ◽  
Membrane Preparation ◽  
Adequate Explanation ◽  
Full Account ◽  
Molecular Weights ◽  
Large Ratio

A full account of the experimental procedures used to determine the number average molecular weights of a series of polyvinyl acetates is given. Adsorption of polyvinyl acetate on a cellophane membrane is demonstrated. The importance of this phenomenon is increased when cells of large ratio of membrane surface to cell volume are used. The presence of small amounts of sodium hydroxide in the membrane eliminates detectable adsorption and alters the osmotic pressure values. This change does not appear to be due to imperfect semipermeability of the membranes, and no adequate explanation of the phenomenon has been as yet discovered.

High Yield Synthesis of Kojic Ester Using Dual Enzymes System and their Antibacterial Activity

2013 ◽  
Vol 594-595 ◽  
pp. 362-369 ◽  
Author(s):  
Salina Mat Radzi ◽  
Nurul Jannah Abd Rahman ◽  
Hanina Mohd Noor ◽  
Mahiran Basri
Keyword(s):  
Reaction Time ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Reaction System ◽  
Bactericidal Effect ◽  
High Yield ◽  
Esterification Reaction ◽  
Optimum Conditions ◽  
Whitening Agent ◽  
Immobilized Lipases

Enzymatic synthesis of kojic ester, a bio-based whitening agent, was successfully carried out via esterification reaction between oleic acid and kojic acid. Commercial immobilized lipases of Novozym 435 and Lipozyme RM IM were used in combination as biocatalyst in the reaction system. Various reaction parameters were chosen to optimize the reaction in order to obtain a high yield of kojic ester including the best ratio of lipases, reaction time and reaction temperature. The optimum conditions for the synthesis of kojic ester was achieved at reaction time of 12 hours, temperature of 60 οC and equal ratio of lipases to produce more than 70 % yield. Antimicrobial tests of synthesized kojic ester towards several types of bacteria via Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) analyses were also examined. The results obtained suggested that kojic ester exhibits a good bactericidal effect towards all bacteria tested such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium.

scholarly journals Innovative environmentally friendly technology for copper(II) hydroxide production

2018 ◽  
Vol 72 (6) ◽  
pp. 363-370
Author(s):  
Milutin Milosavljevic ◽  
Ljiljana Babicev ◽  
Svetlana Belosevic ◽  
Dunja Danicic ◽  
Milena Milosevic ◽  
...  
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Carbonate ◽  
Sodium Hydroxide Solution ◽  
Aqueous Suspension ◽  
Phosphoric Acid Solution ◽  
Sodium Sulphate ◽  
Molar Ratio ◽  
High Yield ◽  
Laboratory Procedure ◽  
Process Stage

The innovative laboratory procedure for the synthesis of copper(II) hydroxide in the form of the aqueous suspension was developed. The reaction mechanism consists of the reaction between copper(II) sulphate pentahydrate and sodium carbonate by successive ion exchange of carbonate ions with the hydroxide ones in a multistep process. Production of copper(II) carbonate and sodium sulphate by reacting of copper(II) sulphate with sodium carbonate was followed by addition of sodium hydroxide solution whereby the product, copper(II) hydroxide, was obtained by releasing an equimolar amount of sodium carbonate. It was determined that, the equimolar reaction of copper(II) sulphate and sodium hydroxide lead to the maximal reactants exploitation. Sodium phosphate, formed in the final process stage by addition of 10 % phosphoric acid solution, acted as a copper(II) hydroxide stabilizer. High yield of the product was obtained by optimizing the synthesis parameters: reaction time, molar ratio of reactants and the reaction temperature. The obtained product was formulated to obtain a commercial product, which is used as a fungicide and bactericide.

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