Fabrication of ultrafine fibrous polytetrafluoroethylene porous membranes by electrospinning

2009 ◽  
Vol 24 (9) ◽  
pp. 2755-2761 ◽  
Author(s):  
Jie Xiong ◽  
Pengfei Huo ◽  
Frank K. Ko
Keyword(s):  
Composite Nanofibers ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Poly Vinyl Alcohol ◽  
Porous Membranes ◽  
Scanning Calorimetry ◽  
Blend Ratio ◽  
Technical Parameters ◽  
Thermogravimetric Analyzer ◽  
Before And After

Poly(vinyl alcohol) (PVA) and poly(tetrafluoroethylene) (PTFE) emulsion were blended with different mass concentrations and the blended spinning solutions were electrospun into composite nanofibers. The influence of the blend ratio of PVA to PTFE and electrospinning technical parameters on the morphology and diameter of the composite nanofibers were investigated. According to the result of thermogravimetric analyzer analysis, the composite membrane was sintered at 390 °C. The membranes were then characterized by differential scanning calorimetry, attenuated total reflection-Fourier transform infrared (ATR-FTIR), and scanning electron microscopy, respectively. The mechanical properties of the membranes before and after sintering were analyzed through tensile testing. The results show that the PTFE porous membranes could be electrospun effectively, thus demonstrating their potential application as filter media.

Exploration for Identification of Sheath-Core Fiber of Ploymer

2014 ◽  
Vol 988 ◽  
pp. 8-12
Author(s):  
Rui Tian Zhu ◽  
Peng Zhang ◽  
Feng Ming Nie
Keyword(s):  
Infrared Spectroscopy ◽  
Accurate Method ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Polymer Fiber ◽  
Reflection Method ◽  
Scanning Calorimetry ◽  
Microscopic Method ◽  
Transmission Technique ◽  
Core Fiber

In this paper, microscopic method, transmission technique and attenuated total reflection method of infrared spectroscopy and differential scanning calorimetry were investigated for analyzing the component of inner and outer layer of sheath-core polymer fiber. Results showed that transmission technique and attenuated total reflection method of infrared spectroscopy was a quick and accurate method for identification of sheath-core fiber of fiber.

Preparation of Polytetrafluoroethylene Ultrafine Fiber Mats with Electrospinning Process

2011 ◽  
Vol 675-677 ◽  
pp. 827-830 ◽  
Author(s):  
Si Jun Zhu ◽  
Yuan Yuan Zhou ◽  
Ochi Takashi ◽  
Gang Wu
Keyword(s):  
Heat Treatment ◽  
Fourier Transform ◽  
Electrospinning Process ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Poly Vinyl Alcohol ◽  
Mass Ratio ◽  
Fiber Mats ◽  
Ultrafine Fibers ◽  
Ultrafine Fiber

Polytetrafluoroethylene (PTFE) ultrafine fibers mats were prepared by electrospinning of an aqueous PTFE dispersion and a small amount of poly(vinyl alcohol) (PVA) and subsequent heat-treatment. The influence of dispersions composition on the morphology of fabricated PTFE ultrafine fiber mats was investigated. The fabricated mats were characterized by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and koniology tester. The results show that the PVA/PTFE mass ratio of 1:5 was suitable for the PTFE fibers formation. All the PVA in the electrospun PVA/PTFE mats was removed at 350 °C~390°C. The fabricated PTFE ultrafine fiber mats have the potential to be used as high-temperature filter.

The properties of sericin/poly(vinyl alcohol) films modified by boric acid

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Qun Wang ◽  
Lu Qi
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Boric Acid ◽  
Vinyl Alcohol ◽  
Water Resistance ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
Blend Ratio ◽  
Percutaneous Drug Delivery ◽  
Thermal Stability Of

AbstractA group of films mainly composed of sericin and poly(vinyl alcohol) (PVA), using boric acid (BA) as a modifier, were prepared by a technique of solution casting. In this work, the effect of BA and sericin on the mechanical properties and water resistance of the films was analyzed, the interior morphology of the films were described by a scanning electron microscopy (SEM), the thermal stability of the films was characterized by differential scanning calorimetry (DSC), and the reaction mechanism was proposed according to the previous literature and the test of Fourier transform infrared spectrum (FTIR). Results indicated that, the properties of the membrane were the functions of the blend ratio of sercin to PVA and the content of BA. The use of BA increased the tensile strength, improved the water resistance and the thermal stability, and varied the interior morphology of the films. The content of sericin greatly influenced the combination of properties of the films, especially the mechanical properties, interior morphology, thermal stability, and water resistance reducing with the increasing of sericin content. The films have potential to be used in materials, such as skin-care coatings for beauty, percutaneous drug delivery systems for exterior intact skin, due to the characteristics of the components and the good mechanical properties of the films.

scholarly journals Organogels for the cleaning of artifacts

2017 ◽  
Vol 89 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Maria Diletta Pianorsi ◽  
Martina Raudino ◽  
Nicole Bonelli ◽  
David Chelazzi ◽  
Rodorico Giorgi ◽  
...  
Keyword(s):  
Release Rate ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Polymeric Networks ◽  
X Ray Scattering ◽  
Paper Document ◽  
New Formulation ◽  
Differential Thermogravimetry

AbstractThe cleaning of artifacts must not alter the original properties of the objects. While the use of free solvents is risky, their confinement into polymeric networks can allow the safe removal of unwanted layers from artifacts. Recently, a methyl 2-methylprop-2-enoate (MMA)-based organogel was formulated as loaded with butan-2-one (MEK), and used to remove aged varnishes from canvas paintings. However, this formulation is not enough retentive to allow its use on paper, where higher retentiveness is needed to avoid the uncontrolled spreading of MEK and dissolved materials. Here, a new PMMA-MEK gel was designed to overcome this limitation. The amount of cross-linker and monomer used in the synthesis of the gel were tuned to achieve optimal retentiveness. Differential scanning calorimetry (DSC), differential thermogravimetry (DTG), small-angle X-ray scattering (SAXS) and attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) provided information on the solvent content, release rate, and mesoporosity of the gel as compared to the previous system. The lower solvent release rate of the new formulation allowed the safe removal of wax that jeopardized a 19th century paper document. The removal was confirmed through optical microscopy and ATR-FTIR, which also highlighted the absence of gel residues on the treated surface.

Debonding mechanism of polymeric fibers in reinforced cementitious composites as a function of crystallinity degree of fibers

2017 ◽  
Vol 52 (3) ◽  
pp. 383-394 ◽  
Author(s):  
Mohamad Ali Etminani ◽  
Farhad Sharif
Keyword(s):  
Surface Chemistry ◽  
Vinyl Alcohol ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Poisson's Ratio ◽  
Degree Of Crystallinity ◽  
Poly Vinyl Alcohol ◽  
Cementitious Composites ◽  
Polymeric Fibers ◽  
Crystallinity Degree

Engineered cementitious composites containing polymeric fibers such as poly(vinyl alcohol) show high tensile ductility and toughness. The aim of the current study was to evaluate the effect of crystallinity degree of poly(vinyl alcohol) fibers on fiber debonding from cementitious matrix in the bending test. In this work, two types of poly(vinyl alcohol) fibers and one grade of polypropylene fiber were separately incorporated in cementitious composites. The chemical structure, surface chemistry, roughness, and microstructure of fibers were examined by Fourier transform infrared, attenuated total reflection, atomic force microscopy, and wide-angle X-ray diffraction tests, respectively. The compression and flexural behaviors of cementitious composites were also assessed. Attenuated total reflection results were indicative of similar surface chemistry for both poly(vinyl alcohol) fibers, while the main difference was observed in the case of degree of crystallinity, which plays an important role in the Poisson’s ratio. Finally, the way in which the degree of crystallinity and Poisson’s ratio of fibers can lead to premature debonding was described and confirmed by scanning electron microscopic images.

scholarly journals Influence of ZnO, SiO2 and TiO2 on the aging process of PLA fibers produced by electrospinning method

2019 ◽  
Vol 140 (4) ◽  
pp. 1769-1778 ◽  
Author(s):  
Karolina Kosowska ◽  
Piotr Szatkowski
Keyword(s):  
Structural Changes ◽  
Uv Light ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Poly Lactic Acid ◽  
Uv Resistance ◽  
Scanning Calorimetry ◽  
Uv Aging ◽  
Electrospinning Method ◽  
Key Factor

Abstract The aim of this work was to study the effect of ceramics particles addition (SiO2, ZnO, TiO2) on the ultraviolet (UV) aging of poly(lactic acid) nonwovens fabricated using electrospinning method. The resistance to aging is a key factor for outdoor and medical applications (UV light sterilization). Nonwovens were placed in special chamber with UV light. Changes of physicochemical properties were recorded using differential scanning calorimetry and attenuated total reflection Fourier-transform infrared spectroscopy. The fibers’ morphology was studied by using scanning electron microscopy. Obtained results clearly showed that only PLA fibers with ZnO particles gained an increase in UV resistance. The paper presents a description of structural changes taking place under the influence of UV aging processes and describes the mechanisms of this process and the effect of ceramic addition on the lifetime of such materials.

scholarly journals Effect of Cryostructuring Treatment on Some Properties of Xanthan and Karaya Cryogels for Food Applications

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2788
Author(s):  
Jonathan Coria-Hernández ◽  
Rosalía Meléndez-Pérez ◽  
Abraham Méndez-Albores ◽  
José Luis Arjona-Román
Keyword(s):  
Food Preservation ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Indirect Contact ◽  
Freeze Thaw ◽  
Food Applications ◽  
Novel Material ◽  
Scanning Electron

Cryogels are novel materials because the manufacturing process known as cryostructuring allows biopolymers to change their properties as a result of repeated controlled freeze–thaw cycles. Hydrogels of xanthan and karaya gums were evaluated after undergoing up to four controlled freeze–thaw cycles in indirect contact with liquid nitrogen (up to −150 °C) to form cryogels. Changes in structural, molecular, rheological, and thermal properties were evaluated and compared to those of their respective hydrogels. Samples were also analyzed by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), Rotational Rheology (RR), Modulated Differential Scanning Calorimetry (MDSC) and zeta potential (ζ). In general, significant differences (p < 0.05) between the numbers of freeze–thaw cycles were found. Karaya cryogels were not stable to repeated cycles of cryostructuring such as the three-cycle xanthan cryogel, which has the best structural order (95.55%), molecular interactions, and thermal stability, which allows the generation of a novel material with improved thermal and structural properties that can be used as an alternative in food preservation.

scholarly journals Vibrational biospectroscopic study and chemical structure analysis of unsaturated polyamides nanoparticles as anti–cancer polymeric nanomedicines using synchrotron radiation

2018 ◽  
Vol 6 (2) ◽  
pp. 167 ◽  
Author(s):  
Alireza Heidari
Keyword(s):  
Fourier Transform ◽  
Synchrotron Radiation ◽  
Ftir Spectroscopy ◽  
Chemical Structure ◽  
Fourier Transform Infrared ◽  
Considerable Change ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Anti Cancer ◽  
Before And After

Firstly, unsaturated polyamides nanoparticles were hardened by continuous synchrotron radiation and then, the induced changes in its chemical structure were studied by Attenuated Total Reflection–Fourier Transform Infrared (ATR–FTIR) spectroscopy. It was shown that applying synchrotron radiation for hardening not only leads to reduction of hardening time but also creates cross link in polymer by breaking Carbon–Carbon double bond, without any considerable change in its chemical structure. In addition, an unsaturated polyamide nanoparticle as anti–cancer polymeric nanomedicines is hardened by synchrotron radiation. Its chemical structure before and after hardening is studied using Raman and Attenuated Total Reflection–Fourier Transform Infrared (ATR–FTIR) spectroscopy. The results show that Raman spectroscopy is considerably better than Attenuated Total Reflection–Fourier Transform Infrared (ATR–FTIR) spectroscopy in detecting the changes happened in chemical structure.  

Comparison of -OH and -NH2 Functional Group Substitution on PTFE Surface with V-UV Photon Irradiation for Protein Adsorption

2004 ◽  
Vol 843 ◽  
Author(s):  
Yuji Sato ◽  
Naoki Kobayashi ◽  
Masataka Murahara
Keyword(s):  
Protein Adsorption ◽  
Functional Group ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Photon Irradiation ◽  
Living Body ◽  
Ptfe Surface ◽  
Before And After ◽  
Biocompatibility Test ◽  
Ft Ir

ABSTRACTPoly-tetrafluoroethylene [PTFE] presents few rejections in a living body but has low tissue affinity. Then, the soft tissue implant material that has not only high biocompatibility but also superb bondability has been developed by photo-chemically substituting the hydrophilic of –OH or –NH2 groups on the PTFE surface with V-UV photon irradiation. The protein adsorption of the sample before and after treatment was also evaluated by scanning electron microscope [SEM] and attenuated total reflection Fourier-transform infrared [ATR FT-IR], using bovine serum albumin [ALB] and fibrin [FIB] solution as a protein index in biocompatibility test. From the results, it has been confirmed that the protein adsorption increased with the increase in the hydrophilic group's substitution density. The -OH incorporated sample adsorbed the ALB and FIB more than the -NH2 incorporated sample; the amount of the ALB and FIB sticking became 2.3 times larger than that of the non-treatment sample.

The Attenuated Total Reflection Infrared Analysis of Surface Crystallinity of Polyhydroxyalkanoates

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Shinn-Gwo Hong ◽  
Wei-Ming Chen
Keyword(s):  
Surface Layer ◽  
Petri Dish ◽  
Weight Percent ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Degree Of Crystallinity ◽  
Infrared Analysis ◽  
Scanning Calorimetry ◽  
Solvent Cast ◽  
Penetration Depths

AbstractThe surface crystallization of three different polyhydroxy alkanoates (PHAs), poly(3-hydroxybutyrate) (PHB), PHB-co-5 weight percent 3-hydroxyvalerate (PHBV5), and PHB-co-12 weight percent 3- hydroxyvalerate (PHBV12), under different processing conditions is analyzed with depth profiling attenuated total reflection spectroscopy (ATR) and differential scanning calorimetry (DSC). The results of ATR indicate that there is a crystallinity distribution on the outer 2 microns thick surface layer. The degree of crystallinity in different penetration depths follows the order of 0.92μ > 0.41μ > 1.70μ for all three hot-pressed PHAs studied and the outer surfaces have a much greater crystallinity than the bulk. The surface crystallinity of specimens is in the order of PHB > PHBV5 > PHBV12 regardless of the different penetration depths analyzed which is consistent with the DSC results. It is also obtained that the effect of annealing in enhancing the crystallization of PHAs is more significant in the surface layer. The surface crystallinity of PHAs obtained after annealing follows the trend of Petri-dish side of solvent-cast PHB > hotpress PHB > air side of solvent-cast PHB > PHBV5 > PHBV12. The difference in crystallinity between the surface and the bulk of PHAs decreases with the addition of 3-hydroxyvalerate but increases after annealing. It is confirmed that the film forming method and the substrate contacted affect the surface crystalline state of PHAs which is attributed to the changes in crystallization conditions in the surface materials.

Sign in / Sign up

Export Citation Format

Share Document