Improvement of Morphology, Structure, and Thermal Properties of Electrospun PVA/RSF Fiber Mats by SiO2

2012 ◽  
Vol 184-185 ◽  
pp. 1017-1020 ◽  
Author(s):  
Yan Hua Liu ◽  
Li Xing Dai

Poly(viny1 alcohol) (PVA)/regenerated silk fibroin (RSF)/silicon dioxide (SiO2) fiber mats were prepared by electrospinning of composite solutions. Fiber morphology was observed under a scanning electron microscope and effects addition of SiO2 was evaluated. Results showed that the obtained fibers exhibited a smooth outer surface, and the continuity was improved because of the different solution conductivity, solution viscosity and compatibility of PVA and RSF by the addition of 1.0 wt. % SiO2. It was found that both Si-O-C linkage and hydrogen bonding interactions were existed among SiO2, PVA, and RSF by FTIR spectroscopy. The addition of SiO2 also resulted in the decrease of crystallinity and increase of thermal properties of electrospun fibers, which were suggested as a result of enhanced compatibility and physical properties of PVA and RSF composite.

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Delaram Fallahi ◽  
Mehdi Rafizadeh ◽  
Naser Mohammadi ◽  
Behrooz Vahidi

AbstractPolystyrene fibers were produced by the electrospinning technique. The effects of solution conductivity, surface tension and concentration on morphology and average diameter of electrospun fibers were investigated by scanning electron microscopy (SEM). Solutions of 12, 10, 8, 6% (w/v) polystyrene in dimethylformamide were prepared. Lithium Chloride and a non-ionic surfactant were used to change the conductivity and surface tension of the solutions, respectively. The results indicate that increasing the solution conductivity eliminates the bead formation and increases the fiber diameters. By addition of salt, fine and consistent fibers could be produced from electrospinning of 8% (w/v) PS/DMF solution. Adding 0.1% surfactant reduces the solution surface tension and results in smaller beads and higher fiber diameters. By increasing the amount of surfactant to 0.3%, big beads and thinner fibers are produced.


2005 ◽  
Vol 877 ◽  
Author(s):  
Pankaj Gupta ◽  
Ramazan Asmatulu ◽  
Rick Claus ◽  
Garth Wilkes

AbstractFlexible field responsive superparamagnetic substrates were prepared by electrospinning a solution of elastomeric polyurethane containing ferrite nanoparticles (ca. 14 nm) of Mn-Zn-Ni. The flexible mats were characterized in terms of fiber morphology and magnetic properties. Field Emission Scanning Electron Microscopy (FESEM) indicated that the diameter of these composite fibers was ca. 300-500 nm. Furthermore, the back-scattered electron FESEM images indicated agglomeration of the nanoparticles at higher wt% (ca 17-26 wt%) loading in the electrospun fibers. The induced specific magnetic saturation and the relative permeability were found to increase linearly with increasing wt% loading of the ferrite nanoparticles on the submicron electrospun fibers. A specific magnetic saturation of 1.7 – 6.3 emu/g at ambient conditions indicated superparamagnetic behavior of these composite electrospun substrates. Additionally, dielectric constant values of the electrospun fibers were measured to be between 2.3 and 5.8.


2021 ◽  
pp. 095400832110130
Author(s):  
Hailong Li ◽  
Sipei Zhao ◽  
Li Pei ◽  
Zihe Qiao ◽  
Ding Han ◽  
...  

Polybenzoxazines are emerging as a class of high-performance thermoset polymers that can find their applications in various fields. However, its practical application is limited by its low toughness. The cyclic β-cyclodextrin and a newly synthesized derivative (β-cyclodextrin-MAH) were separately blended with benzoxazine to improve the toughness of polybenzoxazine. The results revealed that the maximum impact strength of the blend was 12.24 kJ·m−2 and 14.29 kJ·m−2 when 1 wt.% of β-Cyclodextrin and β-Cyclodextrin-MAH, respectively, were used. The strengths were 53% and 86% higher than that of pure polybenzoxazine. The curing reaction, possible chemical structures, and fractured surface were examined using differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy techniques to understand the mechanism of generation of toughness. The results revealed that the sea-island structure and the presence of hydrogen bonds between polybenzoxazine and β-cyclodextrin and β-cyclodextrin-MAH resulted in the generation of toughness. Furthermore, the curves generated during thermogravimetric analysis did not significantly change, revealing the good thermal properties of the system. The phase-separated structure and the hydrogen bonds present in the system can be exploited to prepare synergistically tough polybenzoxazine exhibiting excellent thermal properties. This can be a potential way of modifying the thermoset resins.


TAPPI Journal ◽  
2020 ◽  
Vol 19 (5) ◽  
pp. 239-246
Author(s):  
XIAONING SHEN ◽  
BO LI ◽  
WENXUAN MO ◽  
XIN-SHENG CHAI

This paper presents data on the effects of operational parameters (number of revolutions, linear pressure, and gap) of the PFI refiner on the swellability of recycled fiber, which was characterized by water retention value (WRV). The results showed that the increase of recycled fiber’s WRV was proportional to the number of revolutions and the linear pressure, but inversely proportional to the gap. The mathematical relation between these parameters and the fiber WRV could be described by an empirical model for gaps greater than 0.1 mm. Scanning electron microscopic images of fiber morphology showed that the basic framework of fibers could be maintained with the gap greater than 0.1 mm, but was destroyed with smaller gaps. This model provides a technical reference for quantitative control of refining treatment and an effective method for improving recycled fiber quality.


2017 ◽  
Vol 6 (3) ◽  
pp. 36
Author(s):  
Ghada Abdalla Lotfy Elkholy

Nanotechnology is extensively used in textile industries because it confers unique properties on fabrics.In this study, using nano silicon dioxide (SiO2)-coated nylon fabrics have created a lot of awareness appropriate to improve their functional properties. Using deferent con-struction of nano silicon dioxide (SiO2), the optimization construction are used to carry out treatments impart to improve the roughness, antistatic charge, sew ability, thickness; weight and UPF measurement are investigated. The study evaluates the possibility of using the scanning electron microscope (SEM) to show optimize the effect of treatment of nylon fabrics with nano silicon dioxide not only on the effect of treatment of nylon fabrics with nano silicon dioxide not only on their performance and appearance but also in garment man-ufacturing.


2011 ◽  
Vol 239-242 ◽  
pp. 2679-2682 ◽  
Author(s):  
Rub Nawaz Shahid ◽  
Bin Awais Hasan ◽  
Fahad Ali ◽  
Naeem Ul Haq Tariq

In this work percolation range for Al2O3-Ni interpenetrating phase composite (IPC) was studied to find the optimal combination of electrical conductivity and coefficient of thermal expansion (CTE). The impedance spectroscopy and scanning electron spectroscopy were used to study the percolation limit.


2013 ◽  
Vol 652-654 ◽  
pp. 1846-1850
Author(s):  
Thin Thin Thwe ◽  
Than Than Win ◽  
Yin Maung Maung ◽  
Ko Ko Kyaw Soe

Hydrothermal synthesized lead titanate (PbTiO3¬) powder was prepared in a Teflon-lined stainless steel bomb at different bath temperatures. X-ray diffraction was performed to examine the phase assignment and crystallographic properties of hydrothermal synthesized lead titanate powder. Silicon dioxide (SiO2) was thermally deposited and adapted as intermediate layer on p-Si (100) substrates for MFIS (Metal/Ferroelectric/ Insulator/Semi-conductor) design. The microstructures of PbTiO3 film for both MFS and MFIS designs were observed by scanning electron microscopy (SEM). Charge conduction mechanism was also interpreted by C-2-V relationship. Polarization and electric field characteristics were measured by Sawyer-Tower circuit and good hysteresis nature was formed for both structures of the films. The loop of MFIS was wider than that of MFS cell. Also, the higher value of polarization (Ps=3.21E-03µC/cm2) for MFIS could be explained on the basis of higher dipole moment in this SiO2 buffer layer.


2011 ◽  
Vol 236-238 ◽  
pp. 1336-1341
Author(s):  
Bing Sun ◽  
Yu Xin Liu ◽  
Shu Lan Shi

The Americal Old Corrugated Containers (AOCC) was treated with laccase. Fiber morphology, molecular weight and distribution of lignin were analyzed by scanning electron microscope (SEM) and gel permeation chromatography (GPC). Through the model compound of lignin (ferulic acid) was treated by laccase, the correlative mechanism for improvement of the wet-strength of pulp by laccase was discussed. The results showed that the molecular weight of lignin decreased and the lignin adhered on the fiber surface after the pulp was treated by laccase. While the laccase treated pulp with heating treatment, the condensation degree of lignin and adhesion area on fiber increased. In addition, when the ferulic acid was treated by laccase, the results were similar to AOCC pulp.


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