scholarly journals Characterization of Native and Modified Starches by Potentiometric Titration

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Diana Soto ◽  
Jose Urdaneta ◽  
Kelly Pernia
Keyword(s):  
Potentiometric Titration ◽  
Graft Copolymer ◽  
Itaconic Acid ◽  
Analytical Techniques ◽  
Chemical Oxidation ◽  
Native Starch ◽  
Modified Starches

The use of potentiometric titration for the analysis and characterization of native and modified starches is highlighted. The polyelectrolytic behavior of oxidized starches (thermal and thermal-chemical oxidation), a graft copolymer of itaconic acid (IA) onto starch, and starch esters (mono- and diester itaconate) was compared with the behavior of native starch, the homopolymer, and the acid employed as a graft monomer and substituent. Starch esters showed higher percentages of acidity, followed by graft copolymer of itaconic acid and finally oxidized starches. Analytical techniques and synthesis of modified starches were also described.

Preparation and Characterization of Carboxymethylated and Cross-Linked Enset Starch as a Disintegrant in Tablets

2020 ◽  
Vol 35 (2) ◽  
pp. 119-134
Author(s):  
Yohannes Mengesha ◽  
Anteneh Belete ◽  
Tsige Gebre-Mariam
Keyword(s):  
Reaction Medium ◽  
Moisture Sorption ◽  
Modified Starch ◽  
Disintegration Time ◽  
Native Starch ◽  
Swelling Power ◽  
Sodium Starch Glycolate ◽  
Modified Starches ◽  
The Fourier Transform

Starch and modified starches have been commonly employed as excipient in pharmaceutical industry. The use of non-modified or “native” starch,  However, is mostly confined due to limitation in several physicochemical properties. Cross-linked sodium carboxymethyl starch which is also known as sodium starch glycolate is extensively used in fast dissolving tablets to disperse the drugs within short span of time. In this study, enset starch was carboxymethylated and subsequently cross-linked. Carboxymethyl enset starch (CMES) was obtained by reacting enset starch and monochloroacetic acid (MCA) in the presence of sodium hydroxide. CMESs having different degree of substitution (DS) were cross-linked at variousconcentrations (2.5, 5 and 10% w/w) of sodium hexametaphosphate (SHMP) to provide sodium starch glycolate of enset starch (SSG-E). The fourier transform infrared (FTIR) spectra confirmed the presence of carboxymethylated group in the modified starch granules with new band at 1608.52 cm-1. This dually modified enset starch (SSG-E) was evaluated as a potential disintegrant in paracetamol tablets in comparison with commercially available sodium starch glycolate, Disegel. Carboxymethylation was significantly influenced by reaction medium, reaction temperature and reaction time (p < 0.05). CMES with higher DS (0.437 ± 0.03) exhibited higher peak viscosity than CMES with lower DS (0.224 ± 0.01). Despite exhibiting greater swelling power, CMES showed significantly lower pasting viscosity compared to the native starch (p < 0.05). At 2.5% SHMP, the dually modified starch (SSG-E) exhibited significant increase in swelling but its rate of water-uptake was lower than that of Disegel. As the SHMP concentration wasincreased from 2.5 to 5%, the swelling power decreased significantly (p < 0.05). When the concentration was increased to 10% the swelling power increased significantly (p < 0.05). At 2.5% SHMP concentration SSG-E showed a viscosity comparable to that of CMES. As the concentration of SHMP increased to 5 and to 10% w/w, significant decrease in viscosity (p < 0.05) was observed. Compared to the native enset starch (NES), the solubility of SSG-E was more than 4-fold, but its viscosity was much lower than that of CMESs. The SSG-E exhibited lower moisture sorption than CMES but higher sorption than NES. SSG-E showed good flowability, superior swelling power and solubility than NES. The disintegration time (DT) of paracetamol tablets containing SSG-E as a disintegrant was comparable to those tablets with similar concentration of Disegel. At 4% SSG-E, paracetamol tablets exhibited DT less than 1 min. Keywords: carboxymethylation, degree of cross-linking, enset starch, paracetamol tablets, sodium starch glycolate 

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Some applications of electron beam microanalysis techniques in VLSI process evaluation

1983 ◽  
Vol 41 ◽  
pp. 160-161
Author(s):  
Simon Thomas
Keyword(s):  
Integrated Circuits ◽  
Process Evaluation ◽  
Large Scale ◽  
Technology Development ◽  
Analytical Techniques ◽  
Successful Implementation ◽  
Analysis Of Failures ◽  
Characterization Of Materials ◽  
Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Comparison of Ion-Milling Techniques For Cross-Sectional TEM of Semiconductors

1985 ◽  
Vol 43 ◽  
pp. 166-167
Author(s):  
Julia T. Luck ◽  
C. W. Boggs ◽  
S. J. Pennycook
Keyword(s):  
Analytical Techniques ◽  
Sample Surface ◽  
Ion Milling ◽  
Cross Sectional ◽  
Reliable Technique ◽  
Near Surface ◽  
Transmission Electron ◽  
Thin Region ◽  
Transient Thermal

The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared below. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.

Exploring the characterization of Ni doped MgO nanoparticles using co-precipitation method

2020 ◽  
Vol 3 (1) ◽  
pp. 30-33
Author(s):  
Muthulakshmi M ◽  
Madhumitha G
Keyword(s):  
Magnesium Oxide ◽  
Analytical Techniques ◽  
Nickel Chloride ◽  
Precipitation Method ◽  
Crystalline Powder ◽  
High Melting Point ◽  
Design Synthesis ◽  
Mgo Nanoparticles ◽  
Co Precipitation

Nanotechnology is a field of applied science focused on design, synthesis and characterization of nanomaterials. The nickel and magnesium have improved their applications in transparent electrodes and nano electronics. In addition, magnesium oxide has moisture resistance and high melting point properties. In the present work has been carried out in the development of green crystalline powder of nickel doped magnesium oxide nanoparticles by Co-precipitation method, from the mixture of nickel chloride and magnesium chloride with KOH as solvent. From the XRD results, crystalline size of the particle can be observed. Spherical structure of Ni doped MgO nanoparticles were indicated by SEM results and powdered composition of samples were obtained from FTIR. EDAX represents the peak composition of the nanoparticle. The above analytical techniques have confirmed that the Ni doped MgO nanoparticles obtained from the mixture of NiCl2 and MgCl2.

Synthesis and characterization of some polyimide-epoxy composites

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Toheed Akhter ◽  
Humaira Masood Siddiqi ◽  
Zareen Akhter ◽  
M. Saeed Butt
Keyword(s):  
Thermal Behavior ◽  
Epoxy Resins ◽  
Analytical Techniques ◽  
Char Yield ◽  
Epoxy Composites ◽  
Hydroxyl Group ◽  
Synthesis And Characterization ◽  
Tetracarboxylic Acid ◽  
Epoxy Amine

AbstractComposites from some novel polyimide and commercial epoxy were prepared aiming to improve the thermal behavior of epoxy resins. Two diamines namely 4-4'-diamino-4''-hydroxytriphenyl methane (DHTM) and 4-4'- diaminotriphenyl methane (DTM) were synthesized by reacting aniline and aldehydes according to a reported method. The synthesized diamines were blended with commercially available epoxy 1, 4-butanedioldiglycidylether (BDDE) to synthesize model epoxy amine networks which were compared with polyimideepoxy composites. The polyimides were synthesized by reaction of these diamines with aromatic anhydride namely 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA). These synthesized polyimides were dispersed in epoxy diamine networks to prepare composites. All the monomers and composites were characterized by making use of various analytical techniques including FTIR, NMR, TGA, DSC and XRD. Presence of hydroxyl group in the diamine helped in better dispersion of polyimide leading to high Tg and high char yield at 600 °C.

scholarly journals Extraction Techniques and Analytical Methods for Characterization of Active Compounds in Origanum Species

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4735
Author(s):  
Maša Knez Hrnčič ◽  
Darija Cör ◽  
Jana Simonovska ◽  
Željko Knez ◽  
Zoran Kavrakovski ◽  
...  
Keyword(s):  
Biological Activity ◽  
Abiotic Stresses ◽  
Plant Protection ◽  
Analytical Techniques ◽  
Extraction Techniques ◽  
Isolation And Identification ◽  
Activity Assessment ◽  
Current Contribution ◽  
Pharmaceutical Industries

Phytochemical research based on ethnopharmacology is gaining interest in industries such as functional food, nutraceuticals, cosmetics and pharmaceutical industries. Plants and plant extracts are a rich source of bioactive secondary metabolites. These compounds are often involved in plant protection against biotic or abiotic stresses. The exploitation of available technologies should be oriented and intensified to extend and enhance the continued usefulness of the plants as renewable sources of chemicals, especially medicinal compounds. This current contribution is focused on extraction and analytical techniques for their isolation from the oregano species, their characterization and their potential antioxidative, as well as their antimicrobial, antifungal and anticarcinogenic properties. The work is structured rendering to the different steps involved in the research; starting with extraction and sample preparation, followed by discussing the analytical techniques employed for the isolation and identification of compound/s responsible for the biological activity and methods and techniques for biological activity assessment.

scholarly journals Mineralogical and Microstructure Analysis for Characterization and Provenance of Ceramic Artifacts from Late Helladic Kastrouli Settlement, Delphi (Central Greece)

Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Vayia Xanthopoulou ◽  
Ioannis Iliopoulos ◽  
Ioannis Liritzis
Keyword(s):  
Raw Materials ◽  
Analytical Techniques ◽  
Sem Analysis ◽  
Petrographic Analysis ◽  
Ceramic Assemblage ◽  
Thin Sections ◽  
Central Greece ◽  
High Calcium ◽  
Local Geology

The present study deals with the characterization of a ceramic assemblage from the Late Mycenaean (Late Helladic III) settlement of Kastrouli, at Desfina near Delphi, Central Greece using various analytical techniques. Kastrouli is located in a strategic position supervising the Mesokampos plateau and the entire peninsula and is related to other nearby coeval settlements. In total 40 ceramic sherds and 8 clay raw materials were analyzed through mineralogical, petrographic and microstructural techniques. Experimental briquettes (DS) made from clayey raw materials collected in the vicinity of Kastrouli, were fired under temperatures (900 and 1050 °C) in oxidizing conditions for comparison with the ancient ceramics. The petrographic analysis performed on thin sections prepared from the sherds has permitted the identification of six main fabric groups and a couple of loners. The aplastic inclusions recognized in all fabric groups but one confirmed the local provenance since they are related to the local geology. Fresh fractures of representative sherds were further examined under a scanning electron microscope (SEM/EDS) helping us to classify them into calcareous (CaO > 6%) and non-calcareous (CaO < 6%) samples (low and high calcium was noted in earlier pXRF data). Here, the ceramic sherds with broad calcium separation are explored on a one-to-one comparison on the basis of detailed mineralogical microstructure. Moreover, their microstructure was studied, aiming to estimate their vitrification stage. The mineralogy of all studied samples was determined by means of X-ray powder diffraction (XRPD), permitting us to test the validity of the firing temperatures revealed by the SEM analysis. The results obtained through the various analytical techniques employed are jointly assessed in order to reveal potters’ technological choices.

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