scholarly journals Influence of Thermoplastic PEG, GLY and Zein in PCL/TZ and HAp Bio Composite via Solid State Supercritical CO2 Foaming

2020 ◽  
Vol 17 (2) ◽  
pp. 177
Author(s):  
Istikamah Subuki ◽  
Suffiyana Akhbar ◽  
Farrah Khalidah Nor Wahid
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Solid State ◽  
Porous Structure ◽  
Supercritical Co2 ◽  
Saturation Pressure ◽  
Thermal Characterization ◽  
Foaming Process ◽  
Scanning Electron

This study is aimed to investigate the characteristics of the composite containing blended poly (ɛ-caprolactone) (PCL), hydroxyapatite (HA) and thermoplastic zein (TZ). Thermoplastic zein was developed by mixing zein with glycerol (GLY) and polyethylene glycol (PEG). The thermal characterization of mixed TZ and bio composite was characterized in order to investigate the characterization of PCL/TZ/HA composites. The bio composited was then moulded and produce porous structure via solid state supercritical carbon dioxide (scCO2) foaming process. The specimen was saturated with CO2 for 6 hours at 50˚C and saturation pressure of 20MPa at high depressurization rate. The morphology of porous specimen produced were characterized by scanning electron microscopy (SEM). The results indicated that after polymer saturation with CO2, high depressurization causes the formation of nucleated gas cells that give rise to pores within the foamed specimens. The blended bio composite with composition of PCL60/TZ20/HAp20 exhibit well interconnected porous structure compared to other bio composite prepared. The foaming effect produce foams with heterogeneous morphologies on bio composite material at relatively low temperature.

Solid-State Foaming of Polycaprolactone (PCL)

2007 ◽  
Author(s):  
Hai Wang ◽  
Wei Li ◽  
Vipin Kumar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Room Temperature ◽  
Saturation Pressure ◽  
Crystalline Polymer ◽  
Foaming Process ◽  
Quenching Process ◽  
Foaming Temperature ◽  
Scanning Electron

Polycaprolacton (PCL) is a synthetic biodegradable polymer that is widely used in tissue engineering related studies. It is a semi-crystalline polymer, and has a glass transition temperature (Tg) of −60°C and a melting temperature of 60°C. In this paper, we report on the progress in creating porous PCL foams using the solid-state foaming process. The objective of this study is to examine the foam-ability of PCL using room temperature saturation. PCL specimens were made using compression molding. A “quenching” process was introduced to manipulate the crystallinity of PCL samples. CO2 was used for gas saturation. The effects of saturation pressure and foaming temperature were studied. The created microstructures were characterized using scanning electron microscopy (SEM). The preliminary results have shown that microstructures with pores on the scale of hundreds of nanometers were generated.

Synthesis, Phase Formation and Characterization of Co4Nb2O9 Powders Synthesized by Solid-State Reaction

2008 ◽  
Vol 55-57 ◽  
pp. 873-876 ◽  
Author(s):  
N. Chaiyo ◽  
R. Muanghlua ◽  
A. Ruangphanit ◽  
Wanwilai C. Vittayakorn ◽  
Naratip Vittayakorn
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Solid State Reaction ◽  
Dwell Time ◽  
Single Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Techniques ◽  
Scanning Electron

A corundum-type structure of cobalt niobate (Co4Nb2O9) has been synthesized by a solid-state reaction. The formation of the Co4Nb2O9 phase in the calcined powders was investigated as a function of calcination conditions by differential thermal analysis (DTA) and X-ray diffraction (XRD) techniques. Morphology and particle size have been determined by scanning electron microscopy (SEM). It was found that the minor phases of unreacted Co3O4 tend to form together with the columbite CoNb2O6 phase at a low calcination temperature and short dwell time. It seems that the single-phase of Co4Nb2O9 in a corundum phase can be obtained successfully at the calcination conditions of 900°C for 60 min, with heating/cooling rates of 20°C /min.

Thermal Characterization of Low Grade Wood Polyacylonitrile Composite

2011 ◽  
Vol 214 ◽  
pp. 392-396 ◽  
Author(s):  
Manoj Kumar ◽  
P.L. Sah ◽  
M.G.H. Zaidi ◽  
Anupam Srivastav
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Untreated Wood ◽  
Thermal Characterization ◽  
Low Grade ◽  
Eucalyptus Wood ◽  
Scanning Electron

A series of wood polyacrylonitrile (PAN) composites (WPCs) were synthesized through impregnation polymerization of Eucalyptus wood (Eucalyptus Grandies) by acrylonitrile (AN) in methanol (20-60% v/v) in the presence of benzoyl peroxide (1.0% w/v) in benzene medium at 70 ±10C. This resulted in corresponding WPCs with polyacrylonitrile (PAN) loading in the range of 15.5-20%. Loading of PAN into wood, as ascertained through TGA, DTGA and DTA and supported by Fourier Transform Infrared Spectroscopy (FTIR) as well as Scanning Electron Microscopy (SEM) was found to increase the resistance against thermo-oxidation of WPCs in comparison to untreated wood.

Characterization of Deposits on Silicone Contact Lenses from Clinical Wear Studies

1977 ◽  
Vol 35 ◽  
pp. 174-175
Author(s):  
H. Freeman ◽  
R. Berta
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Carbon Dioxide ◽  
Contact Lenses ◽  
Biological Species ◽  
Chemical Information ◽  
Clinical Program ◽  
Metabolic Imbalance ◽  
Scanning Electron

Contact lenses made from silicone elastomer have been made and tested because of the inherent permeability of silicones to gases. Adequate transfer of such gases as oxygen and carbon dioxide through the Silcon® lens tends to minimize metabolic imbalance at the cornea. This property offers the potential for comfortable extended wear of Silcon® lenses. However, as in other man-made materials interacting with body processes, silicone contact lenses are subject to the accumulation of biological materials which gradually impair visual acuity. Morphological and chemical information about the accumulation has been gained by the use of replication electron microscopy, scanning electron microprobe; and identification of biological species by mass spectrometry.Silicone contact lenses were dispensed to patients in the course of an experimental clinical program during which frequent examinations were made of the patient's eyes and lenses. Lens care regimens were carefully specified.

scholarly journals Foaming of Polycaprolactone and Its Impregnation with Quercetin Using Supercritical CO2

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1390 ◽  
Author(s):  
Ignacio García-Casas ◽  
Antonio Montes ◽  
Diego Valor ◽  
Clara Pereyra ◽  
Enrique J. Martínez de la Ossa
Keyword(s):  
Electron Microscopy ◽  
Supercritical Co2 ◽  
The Other ◽  
Heterogeneous Structure ◽  
Significant Delay ◽  
Scanning Calorimetry ◽  
Foam Structure ◽  
X Ray ◽  
Scanning Electron

Foamed polycaprolactone impregnated with quercetin was carried out with a batch foaming technique using supercritical CO2. The experimental design was developed to study the influence of pressure (15–30 MPa), temperature (308–333 K), and depressurization rate (0.1–20) on the foam structure, melting temperature, and release tests of composites. The characterization of the experiments was carried out using scanning electron microscopy, X-ray diffractometer, and differential scanning calorimetry techniques. It was observed that the porosity created in the polymer had a heterogeneous structure, as well as the impregnation of the quercetin during the process. On the other hand, controlled release tests showed a significant delay in the release of quercetin compared to commercial quercetin.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

Characterization of CMOS Structures (0.6 µm process) Submitted to HBM and COM ESD Stress Tests

1997 ◽  
Author(s):  
G. Meneghesso ◽  
E. Zanoni ◽  
P. Colombo ◽  
M. Brambilla ◽  
R. Annunziata ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrostatic Discharge ◽  
Stress Test ◽  
Complete Characterization ◽  
Stress Tests ◽  
Test Procedures ◽  
Emission Microscopy ◽  
Fast Rise ◽  
Scanning Electron

Abstract In this work, we present new results concerning electrostatic discharge (ESD) robustness of 0.6 μm CMOS structures. Devices have been tested according to both HBM and socketed CDM (sCDM) ESD test procedures. Test structures have been submitted to a complete characterization consisting in: 1) measurement of the tum-on time of the protection structures submitted to pulses with very fast rise times; 2) ESD stress test with the HBM and sCDM models; 3) failure analysis based on emission microscopy (EMMI) and Scanning Electron Microscopy (SEM).

Isolasi Dan Karakterisasi Bentonit Alam Menjadi Nanopartikel Monmorillonit

2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Zaimahwati Zaimahwati ◽  
Yuniati Yuniati ◽  
Ramzi Jalal ◽  
Syahman Zhafiri ◽  
Yuli Yetri
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Surface Morphology ◽  
Average Diameter ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Scanning Electron ◽  
Sedimentation Processes

<p>Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara.  Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.</p><p><em>In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes.  The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.</em></p>

Sign in / Sign up

Export Citation Format

Share Document