scholarly journals Water Resistant Self-Extinguishing Low Frequency Soundproofing Polyvinylpyrrolidone Based Electrospun Blankets

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1205 ◽  
Author(s):  
Jessica Passaro ◽  
Paolo Russo ◽  
Aurelio Bifulco ◽  
Maria Teresa De Martino ◽  
Veronica Granata ◽  
...  
Keyword(s):  
Preliminary Investigation ◽  
Low Frequency ◽  
Electrospinning Process ◽  
Thermal Treatments ◽  
Polar Group ◽  
Scanning Calorimetry ◽  
Absorption Properties ◽  
Produce Water ◽  
Polar Groups ◽  
Silica Gel Particles

This paper shows that an eco-friendly electrospinning process allows us to produce water resistant sound absorbers with reduced thickness and excellent sound-absorption properties in the low and medium frequency range (250–1600 Hz) for which which human sensitivity is high and traditional materials struggle to match, that also pass the fire tests which are mandatory in many engineering areas. The structure and composition were studied through Scanning Electron Microscopy (SEM), Fourier Transform InfraRed (FTIR) Spectroscopy and ThermoGravimetric Analysis (TGA). The density, porosity and flow resistivity were measured. Preliminary investigation of the thermal conductivity through Differential Scanning Calorimetry (DSC) shows that they have perspectives also for thermal insulation. The experimental results indicate that the achievements are to be ascribed to the chemical nature of Polyvinylpyrrolidone (PVP). PVP is, in fact, a polymeric lactam with a side polar group that may be easily released by a thermooxidative process. The side polar groups allow for using ethanol for electrospinning than relying on a good dispersion of silica gel particles. The silica particles dimensionally stabilize the mats upon thermal treatments and confer water resistance while strongly contributing to the self-extinguishing property of the materials.

scholarly journals Biocompatibility studies of polyurethane electrospun membranes based on arginine as chain extender

2021 ◽  
Vol 32 (9) ◽  
Author(s):  
Georgina Alejandra Venegas-Cervera ◽  
Andrés Iván Oliva ◽  
Alejandro Avila-Ortega ◽  
José Manuel Cervantes-Uc ◽  
Leydi Maribel Carrillo-Cocom ◽  
...  
Keyword(s):  
Fourier Transforms ◽  
Cell Attachment ◽  
Human Fibroblasts ◽  
Gel Permeation Chromatography ◽  
Electrospinning Process ◽  
Chain Extender ◽  
Cellular Interaction ◽  
Scanning Calorimetry ◽  
Polyurethane Membranes ◽  
Electrospun Membranes

AbstractElectrospun polymers are an example of multi-functional biomaterials that improve the material-cellular interaction and aimed at enhancing wound healing. The main objective of this work is to fabricate electrospun polyurethane membranes using arginine as chain extender (PUUR) in order to test the fibroblasts affinity and adhesion on the material and the polymer toxicity. Polyurethane membranes were prepared in two steps: (i) the polyurethane synthesis, and ii) the electrospinning process. The membranes were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques. The evaluation of PUUR as a scaffolding biomaterial for growing and developing of cells on the material was realized by LIVE/DEAD staining. The results show that the fluorescent surface area of human fibroblasts (hFB), was greater in control dense membranes made from Tecoflex than in electrospun and dense PUUR. From SEM analysis, the electrospun membranes show relatively uniform attachment of cells with a well-spread shape, while Tecoflex dense membranes show a non-proliferating round shape, which is attributed to the fiber’s structure in electrospun membranes. The cell morphology and the cell attachment assay results reveal the well spreading of hFB cells on the surface of electrospun PUUR membranes which indicates a good response related to cell adhesion.

Influence of thermal treatments on the low frequency conductivity and microwave dielectric loss of CaTiO3 ceramics

2011 ◽  
Vol 176 (5) ◽  
pp. 401-405 ◽  
Author(s):  
Peng Hu ◽  
Huan Jiao ◽  
Chun-Hai Wang ◽  
Xiao-Ming Wang ◽  
Shi Ye ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Low Frequency ◽  
Thermal Treatments ◽  
Microwave Dielectric

scholarly journals Influence of spacer chain lengths and polar terminal groups on the mesomorphic properties of tethered 5-phenylpyrimidines

2009 ◽  
Vol 5 ◽  
Author(s):  
Gundula F Starkulla ◽  
Elisabeth Kapatsina ◽  
Angelika Baro ◽  
Frank Giesselmann ◽  
Stefan Tussetschläger ◽  
...  
Keyword(s):  
Terminal Group ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Maximum Phase ◽  
X Ray ◽  
Smectic A ◽  
Polar Groups ◽  
Chain Lengths ◽  
Mesomorphic Properties ◽  
Phase Width

Based on 5-(4-hydroxyphenyl)-2-octylpyrimidine 8, 5-phenylpyrimidine derivatives 3–7, 9 with different spacer chain lengths (C2 up to C6) and different terminal polar groups (Br, Cl, N3, OH, CN) were synthesized by etherification and nucleophilic substitution. The mesomorphic behaviour of these compounds was investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXS and SAXS) and revealed smectic A mesophases for bromides, chlorides and azides 3, 4 and 6. For these compounds a maximum phase width was observed for the C5 spacer regardless of the terminal group, whereas the hydroxy- and cyano-substituted derivatives 5 and 7, respectively, were non mesomorphic and showed only melting transitions.

Facile synthesis and enhanced microwave absorption properties of anthracite-based carbon/Ni3Fe/NiO ternary composites

2020 ◽  
Vol 44 (33) ◽  
pp. 13962-13970
Author(s):  
Hengdong Ren ◽  
Jialin Ma ◽  
Jun Zhou ◽  
Xiangfeng Shu ◽  
Zhenying Liu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Microwave Radiation ◽  
Low Frequency ◽  
Microwave Absorber ◽  
Facile Synthesis ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Radiation Method ◽  
Microwave Radiation Method

A low-frequency microwave absorber was synthesized by using a microwave radiation method.

scholarly journals Structure and Physicochemical Properties of Water Treated under Methane with Low-Temperature Glow Plasma of Low Frequency

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1638 ◽  
Author(s):  
Aleksandra Ciesielska ◽  
Wojciech Ciesielski ◽  
Karen Khachatryan ◽  
Henryk Koloczek ◽  
Damian Kulawik ◽  
...  
Keyword(s):  
Low Temperature ◽  
Physicochemical Properties ◽  
Treatment Time ◽  
Low Frequency ◽  
Aqueous Solubility ◽  
Physicochemical Characteristics ◽  
Scanning Calorimetry ◽  
Spin Resonance ◽  
Reflectance Ftir ◽  
Glow Plasma

Our former studies delivered a strong evidence that water indirectly treated with low-temperature, low-pressure glow plasma of low frequency (GP) changed its structure depending on the atmosphere in which such treatment was performed (air, ammonia, and nitrogen) and on the time of the treatment (0 to 120 min). In every case, water of different physicochemical characteristics and interesting biological functions was produced. Therefore, the relevant studies were extended to treating deionized water with GP under methane. The resulting samples were characterized by means of ultraviolet/visible (UV/VIS), Fourier transformation infrared-attenuated total reflectance (FTIR-ATR), electron spin resonance (ESR) and Raman spectroscopies, differential scanning calorimetry (DSC), thermogravimetry, pH, conductivity, and refractive index. The generated samples of water had entirely different physicochemical properties from those recorded for water treated with GP in the air and under both ammonia and nitrogen. The treatment of water with GP under methane did not produce clathrates hosting methane molecules. Thermogravimetry delivered an evidence that the treatment with GP increased the aqueous solubility of methane. That solubility non-linearly changed against the treatment time.

Role of interfacial interaction on the crystallization behavior and melting characteristics of PP/Nano-CaCO3 composites modified with different compatibilizers

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuhai Wang ◽  
Hao Shen ◽  
Gu Li ◽  
Kancheng Mai
Keyword(s):  
Synergistic Effect ◽  
Heterogeneous Nucleation ◽  
Crystallization Temperature ◽  
Crystallization Behavior ◽  
Crystallization Rate ◽  
Interfacial Interaction ◽  
Scanning Calorimetry ◽  
Polar Groups ◽  
Melting Characteristics

AbstractPP/nano-CaCO3 composites with different interfacial interaction were prepared by addition of compatibilizers with the same polar groups but different backbones. The non-isothermal and isothermal crystallization behavior of PP/nano- CaCO3 composites was investigated using differential scanning calorimetry (DSC). The results indicated that the interfacial interaction between PP and nano-CaCO3 increased the crystallization temperature and crystallization rate of PP due to the heterogeneous nucleation of nano-CaCO3. The interfacial interaction between nano- CaCO3 and compatibilizer further increased the crystallization temperature and crystallization rate of PP and induced the formation of β-crystal of PP due to the synergistic effect of heterogeneous nucleation between nano-CaCO3 and compatibilizer. This synergistic effect of heterogeneous nucleation between nano- CaCO3 and compatibilizer depended on the interfacial interaction between compatibilizer and PP matrix. The increased compatibility between compatibilizer and PP matrix favoured the heterogeneous nucleation between nano-CaCO3 and compatibilizer

scholarly journals Improvement of the Firocoxib Dissolution Performance Using Electrospun Fibers Obtained from Different Polymer/Surfactant Associations

2019 ◽  
Vol 20 (12) ◽  
pp. 3084 ◽  
Author(s):  
Lauretta Maggi ◽  
Valeria Friuli ◽  
Enrica Chiesa ◽  
Silvia Pisani ◽  
Mirena Sakaj ◽  
...  
Keyword(s):  
Amorphous State ◽  
Electrospinning Process ◽  
Electrospun Fibers ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Water Interaction ◽  
Remarkable Improvement ◽  
Polymer Surfactant ◽  
Carrier Systems ◽  
Scanning Electron

An electrospinning process was optimized to produce fibers of micrometric size with different combinations of polymeric and surfactant materials to promote the dissolution rate of an insoluble drug: firocoxib. Scanning Electron Microscopy (SEM) showed that only some combinations of the proposed carrier systems allowed the production of suitable fibers and further fine optimization of the technique is also needed to load the drug. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) suggest that the drug is in an amorphous state in the final product. Drug amorphization, the fine dispersion of the active in the carriers, and the large surface area exposed to water interaction obtained through the electrospinning process can explain the remarkable improvement in the dissolution performance of firocoxib from the final product developed.

Raman Spectroscopic Study of Phase Coexistence in Binary Phospholipid Bilayers

2020 ◽  
Vol 75 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Sergey V. Adichtchev ◽  
Konstantin A. Okotrub ◽  
Alexey M. Pugachev ◽  
Irina V. Zaytseva ◽  
Nikolay V. Surovtsev
Keyword(s):  
Raman Line ◽  
Low Frequency ◽  
Phospholipid Bilayers ◽  
Phase Coexistence ◽  
Lipid Phase ◽  
Label Free ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Raman Spectroscopic ◽  
Raman Scattering Spectra

Binary phospholipid bilayers composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine and 1,2-palmitoyl-sn-glycero-3-phosphocholine (DPPC) were studied by Raman spectroscopy and differential scanning calorimetry (DSC). We examined features in Raman scattering spectra that are sensitive to the lipid phase and, therefore, could indicate the phase coexistence. It was found that the low-frequency half-width of half-maximum (LHWHM) of the 2850 cm−1 Raman line, corresponding to the symmetric CH2 stretching vibrations, unequivocally reveals the coexisting phospholipids in ordered and disordered conformational states, which correspond to ordered and disordered phases coexistence, in the DPPC mole concentration range from 0.4 to 0.9. The phase coexistence in this concentration range was supported by the particular concentration behavior of the ratio between the intensities of the 2880 cm−1 antisymmetric CH2 vibration line and the 2850 cm−1 symmetric one. It was also shown that the spectral shape of the 1300 cm−1 Raman line, corresponding to the CH2 twisting vibrations, is a good indicator for the phase state and phase coexistence in the phospholipid bilayers. Comparison with the DSC curves confirmed that in the DPPC mole concentration range from 0.4 to 0.9, the two phase transition peaks are observed in DSC curve, those positions are independent of the DPPC concentration. The outcome of the study is the robust label-free contactless approach for the detection of the lipid phase separation, which can be realized with the micrometer resolution.

scholarly journals Proton Conductivity through Polybenzimidazole Composite Membranes Containing Silica Nanofiber Mats

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1182 ◽  
Author(s):  
Escorihuela ◽  
García-Bernabé ◽  
Montero ◽  
Andrio ◽  
Sahuquillo ◽  
...  
Keyword(s):  
Composite Membranes ◽  
Electrospinning Process ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix ◽  
Efficient Energy ◽  
The Past ◽  
Polar Groups ◽  
Nanofiber Mats ◽  
Thermal Stability Of ◽  
Energy Converting

The quest for sustainable and more efficient energy-converting devices has been the focus of researchers′ efforts in the past decades. In this study, SiO2 nanofiber mats were fabricated through an electrospinning process and later functionalized using silane chemistry to introduce different polar groups OH (neutral), SO3H (acidic) and NH2 (basic). The modified nanofiber mats were embedded in PBI to fabricate mixed matrix membranes. The incorporation of these nanofiber mats in the PBI matrix showed an improvement in the chemical and thermal stability of the composite membranes. Proton conduction measurements show that PBI composite membranes containing nanofiber mats with basic groups showed higher proton conductivities, reaching values as high as 4 mS·cm−1 at 200 C.

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