Investigating the influence of temperature on electrospinning of polycaprolactone solutions

e-Polymers ◽  
2014 ◽  
Vol 14 (5) ◽  
pp. 323-333 ◽  
Author(s):  
Soghra Ramazani ◽  
Mohammad Karimi
Keyword(s):  
Electron Microscopy ◽  
Molecular Orientation ◽  
Fiber Diameter ◽  
Minimum Size ◽  
Effect Of Temperature ◽  
Electrospun Fibers ◽  
Influence Of Temperature ◽  
Set Point ◽  
Influence Of Temperature On ◽  
Scanning Electron

AbstractThe present work shows the effect of temperature on successfully obtained uniform electrospun poly-(ε-caprolactone) (PCL) fibers, with specific attention to the molecular orientation and diameter of nanofibers. Experiments were performed at temperatures (T) of 25°, 35°, and 45°C, and at PCL concentrations (w) of 12, 16, and 20 wt.%. Scanning electron microscopy provided the morphology of electrospun fibers and quantified their diameters. Elevated temperature for all PCL concentrations yielded a viscosity that allows for easier stretching of the jet to obtain a smaller diameter for fibers. A minimum size of the fiber diameter (close to 100 nm) was achieved for the set point T=45°C and w=12 and 16 wt.%. Due to the easy stretching of the jet by controlling the elastic property of the solution, a dichroic ratio of 1.62 was accessible for the set point T=35°C and w=12 wt.% from polarized Fourier transform infrared spectra as a factor for the orientation of PCL chains.

Study of the Influence of Temperature on the Optical and Structural Properties of Dolomite

2020 ◽  
Vol 74 (10) ◽  
pp. 1280-1286
Author(s):  
Lucas Train Loureço ◽  
Celso de Araujo Duarte ◽  
Dietmar William Foryta ◽  
Bruno Guimarães Titon ◽  
Eleonora Maria Gouvêa Vasconcellos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Treatment ◽  
X Ray Diffraction ◽  
Electron Dispersive Spectroscopy ◽  
Influence Of Temperature ◽  
X Ray ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Scanning Electron

The present work reports the results of structural and optical investigations in samples of natural dolomite, subjected to thermal treatment at different temperatures (500 ℃ to 700 ℃) and times (one up to three hours). The motivation is the evaluation of the changes that may occur in carbonaceous asteroids and meteorites, respectively, subjected to the action of the solar radiation and heated during the fall in the atmosphere. We carried out scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction, optical reflectance and photoluminescence measurements

Measuring size-dependent mechanical properties of electrospun polystyrene fibers using in-situ AFM-SEM

2012 ◽  
Vol 1424 ◽  
Author(s):  
Russell J. Bailey ◽  
Beatriz Cortes-Ballesteros ◽  
Hao Zhang ◽  
Congwei Wang ◽  
Asa H. Barber
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Fiber Diameter ◽  
Electrospun Fibers ◽  
Force Microscopy ◽  
Size Dependent ◽  
Atomic Force ◽  
Scanning Electron

ABSTRACTThe mechanical properties of individual electrospun polystyrene fibers with sub-micron diameters were measured using a combination of atomic force microscopy (AFM) and scanning electron microscopy (SEM). The strain to failure of the electrospun fibers was observed to increase as the fiber diameter decreased. This size dependent mechanical behavior in individual electrospun polystyrene fibers indicates a suppression of localized failure and a shift away from crazing that is dominant in bulk samples.

scholarly journals Investigation of the Fiber, Bulk, and Surface Properties of Meltblown and Electrospun Polymeric Fabrics

2004 ◽  
Vol os-13 (3) ◽  
pp. 1558925004os-13
Author(s):  
Peter P. Tsai ◽  
WeiWei Chen ◽  
J. Reece Roth
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fiber Diameter ◽  
Electrospinning Process ◽  
Electrospun Fibers ◽  
Microscopic Structure ◽  
Electrospun Nanofiber ◽  
Sem Images ◽  
Nylon Fabric ◽  
Scanning Electron

We measured and compared the properties of meltblown and electrospun fabrics made of nylon and polyurethane (PU). Properties of interest included surface energy/wettability, strength, fiber diameter, and microscopic structure as revealed by scanning electron microscopy (SEM). We also report new data on the diameters of electrospun fibers measured from digitized SEM images of electrospun nylon, polyurethane (PU), polyacrylonitrile (PAN), polycaprolactone (PCL), and polycarbonate (PC) fabrics. The electrospinning process produced fibers with diameters in the range from 10 nm to several microns. It was found that the strength per unit areal weight of electrospun nanofiber nylon fabric was up to ten times that of the meltblown material, and for polyurethane (PU) fabric, from 2.5–3 times that of the melt-blown material.

Reactivity Towards O2 and NO of the Soot Formed from Ethylene Pyrolysis at Different Temperatures

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
M Pilar Ruiz ◽  
Alicia Callejas ◽  
Angela Millera ◽  
María U. Alzueta ◽  
Rafael Bilbao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Gas Chromatography ◽  
Raman Spectroscopy ◽  
Residence Time ◽  
Formation Temperature ◽  
Influence Of Temperature ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Scanning Electron

The influence of temperature on the formation of soot from ethylene pyrolysis has been studied. Pyrolysis experiments were carried out in a quartz reactor in the 1000-1200 °C temperature range, for an inlet C2H4 concentration of 50000 ppmv and a gas residence time of 4552/T(K) seconds. Outlet gases were analyzed by gas chromatography and the amount of soot produced measured. The reactivity of the soot samples obtained towards O2 and NO was also studied. Results show that the higher the formation temperature, the less reactive the soot. The soot samples were further characterized using elemental analysis, scanning electron microscopy and Raman spectroscopy, in order to study their structural properties, and relate them to their reactivity. Additionally, a comparison of the reactivity towards NO between acetylene and ethylene soot samples obtained under similar conditions has been carried out. The soot samples obtained from ethylene pyrolysis present higher reactivity towards NO than the soot samples formed from acetylene.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

Research on dynamic characteristics of gear system considering the influence of temperature on material performance

2021 ◽  
pp. 107754632110026
Author(s):  
Zhou Sun ◽  
Siyu Chen ◽  
Xuan Tao ◽  
Zehua Hu
Keyword(s):  
Elastic Modulus ◽  
Dynamic Characteristics ◽  
Poisson’S Ratio ◽  
Gear System ◽  
Poisson's Ratio ◽  
Effect Of Temperature ◽  
Time Varying ◽  
Influence Of Temperature ◽  
Meshing Stiffness ◽  
Influence Of Temperature On

Under high-speed and heavy-load conditions, the influence of temperature on the gear system is extremely important. Basically, the current work on the effect of temperature mostly considers the flash temperature or the overall temperature field to cause expansion at the meshing point and then affects nonlinear factors such as time-varying meshing stiffness, which lead to the deterioration of the dynamic transmission. This work considers the effect of temperature on the material’s elastic modulus and Poisson’s ratio and relates the temperature to the time-varying meshing stiffness. The effects of temperature on the elastic modulus and Poisson’s ratio are expressed as functions and brought into the improved energy method stiffness calculation formula. Then, the dynamic characteristics of the gear system are analyzed. With the bifurcation diagram, phase, Poincaré, and fast Fourier transform plots of the gear system, the influence of temperature on the nonlinear dynamics of the gear system is discussed. The numerical analysis results show that as the temperature increases, the dynamic response of the system in the middle-speed region gradually changes from periodic motion to chaos.

Flow Behaviors of High Acyl Gellan Aqueous Solutions as Affected by Temperature, and Calcium and Gellan Concentrations

2008 ◽  
Vol 4 (5) ◽  
Author(s):  
Yiqun Huang ◽  
Pawan Singh Takhar ◽  
Juming Tang ◽  
Barry G Swanson
Keyword(s):  
Shear Rate ◽  
Aqueous Solutions ◽  
Apparent Viscosity ◽  
Flow Resistance ◽  
Effect Of Temperature ◽  
Temperature Changes ◽  
Influence Of Temperature ◽  
Rheological Behaviors ◽  
Low Concentrations ◽  
Influence Of Temperature On

Rheological behaviors of high acyl (HA) gellan are not well understood partially because of its relatively late commercialization compared to low acyl gellan. The objective of this study was to investigate the effect of temperature (5-30 °C), calcium (0, 1 and 10 mM) and gellan concentrations (0.0044-0.1000% w/v) on the flow behaviors of high acyl gellan aqueous solutions using rheological tests. Gellan solutions with 0 or 1 mM added Ca++ exhibited shear thinning behavior at gellan concentrations above 0.0125%. The influence of temperature on apparent viscosity (shear rate, 100 s-1) of gellan solutions can be described with an Arrhenius relationship. The apparent viscosity of gellan solution at low concentrations was more sensitive to temperature changes. The addition of Ca++ led to a decrease in flow resistance for a dilute gellan solution (<0.0125%), but an increased resistance for a relatively concentrated gellan solution (>0.0125%).

SIZE-INDUCED EFFECTS IN NANOSTRUCTURED NiFe2O4

2010 ◽  
Vol 24 (30) ◽  
pp. 5973-5985
Author(s):  
M. GUNES ◽  
H. GENCER ◽  
T. IZGI ◽  
V. S. KOLAT ◽  
S. ATALAY
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Structural Parameters ◽  
Hydrothermal Process ◽  
Lattice Parameter ◽  
Effect Of Temperature ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

NiFe 2 O 4 nanoparticles were successfully prepared by a hydrothermal process, and the effect of temperature on them was studied. The particles were annealed at various temperatures ranging from 413 to 1473 K. Studies were carried out using powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, differential thermal analysis, thermogravimetric analysis and a vibrating sample magnetometer. The annealing temperature had a significant effect on the magnetic and structural parameters, such as the crystallite size, lattice parameter, magnetization and coercivity.

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