Bismuth Trioxide Doped Polyamide 6.6 Nanocomposites for Electrically Insulating Materials

Composite Fibers ◽

Scanning Calorimetry ◽

Bismuth Trioxide ◽

Micro Particles ◽

Nanocomposite Fibers ◽

Polyamide 6.6 ◽

High Dielectric

Abstract Polymer-based insulators have attracted much attention amongst researchers due to their various advantages such as light weightness, lower cost and ease of production. In this study, it is aimed to manufacture lightweight and thin insulator by electrospun composite fibers and to observe the effect of bismuth oxide (Bi2O3) on insulating property of polymer-based composite structure. For that purpose, polyamide 6.6 polymer (PA6.6) with high dielectric constant was doped with bismuth trioxide micro particles and it was used for coating polyester spunbonds by electrospinning technique. Morphological properties, thermal behaviours and electrical resistance of coated spunbonds were investigated. Scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy (EDX) showed that Bi2O3 was succesfully adapted into fiber structure and nano-scale PA6.6/Bi2O3 composite fibers were obtained. Thermal behaviours of coated samples were developed by increasing Bi2O3 loading according to differential scanning calorimetry (DSC) and thermogravimetic analysis (TGA) results. Addition of Bi2O3 caused remarkable increase on electrical resistance of PA6.6 electrospun surfaces. Bi2O3/PA6.6. nanocomposite fibers are promising and good candidates for thin electrically insulating polymer-based structures for micro- or nanodimensional devices.

Electrospinning of Chitosan Biopolymer and Polyethylene Oxide Blends

Autex Research Journal ◽

10.2478/aut-2019-0031 ◽

2020 ◽

Vol 20 (4) ◽

pp. 426-440

Author(s):

Sandra Varnaitė-Žuravliova ◽

Natalja Savest ◽

Julija Baltušnikaitė-Guzaitienė ◽

Aušra Abraitienė ◽

Andres Krumme

Keyword(s):

Electrical Conductivity ◽

Molecular Weight ◽

Polyethylene Oxide ◽

Synthetic Polymer ◽

Low Molecular Weight ◽

Fibrous Materials ◽

Scanning Calorimetry ◽

Tissue Scaffold

AbstractThe objective of this study is to investigate the morphological (scanning electron microscopicy images), thermal (differential scanning calorimetry), and electrical (conductivity) properties and to carry out compositional analysis (Fourier-transform infrared) of produced nonwoven fibrous materials adapted in biomedical applications as scaffolds. The orientation of produced nanofilaments was also investigated because it is considered as one of the essential features of a perfect tissue scaffold. Viscosity and electrical conductivity of solutions, used in the manufacturing process, were also disassembled because these properties highly influence the morphological properties of produced nanofibers. The nanofibrous scaffolds were fabricated via conventional electrospinning technique from biopolymer, synthetic polymer, and their blends. The chitosan (CS) was chosen as biopolymer and polyethylene oxide (PEO) of low molecular weight as synthetic polymer. Solutions from pure CS were unspinnable: beads instead of nanofibers were formed via spinning. The fabrication of pure PEO nanomats from solutions of 10 wt%, 15 wt%, and 20 wt% concentrations (in distilled water) turned out to be successful. The blending of composed CS solutions with PEO ones in ratios of 1:1 optimized the parameters of electrospinning process and provided the opportunity to fabricate CS/PEO blends nanofibers. The concentration of acetic acid (AA) used to dissolve CS finely spuninned the nanofibers from blended solutions and influenced the rate of crystallization of manufactured fiber mats. The concentration of PEO in solutions as well as viscosity of solutions also influenced the diameter and orientation of formed nanofibers. The beadless, highly oriented, and defect-free nanofibers from CS/PEO solutions with the highest concentration of PEO were successfully electrospinned. By varying the concentrations of AA and low molecular weight PEO, it is possible to fabricate beadless and highly oriented nanofiber scaffolds, which freely can found a place in medical applications.

Encapsulation of Diclofenac Molecules into Poly(-Caprolactone) Electrospun Fibers for Delivery Protection

Journal of Nanomaterials ◽

10.1155/2009/238206 ◽

2009 ◽

Vol 2009 ◽

pp. 1-8 ◽

Cited By ~ 23

Author(s):

Loredana Tammaro ◽

Giuseppina Russo ◽

Vittoria Vittoria

Keyword(s):

Diclofenac Sodium ◽

Composite Fibers ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

In Vitro Drug Release ◽

Good Thermal Stability ◽

Fibrous Membranes ◽

Poly Caprolactone

Mg-Al Hydrotalcite-like clay (LDH) intercalated with diclofenac anions (HTlc-DIC) was introduced into poly(-caprolactone) (PCL) in different concentrations by the electrospinning technique, and mats of nonwoven fibers were obtained and compared to the pristine pure electrospun PCL. The fibers, characterized by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry, show an exfoliated clay structure up to 3 wt%, a good thermal stability of the diclofenac molecules and a crystallinity of PCL comparable to the pure polymer. The scanning electron microscopy revealed electrospun PCL and PCL composite fibers diameters ranging between 500 nm to 3.0 m and a generally uniform thickness along the fibers. As the results suggested the in vitro drug release from the composite fibers is remarkably slower than the release from the corresponding control spun solutions of PCL and diclofenac sodium salt. Thus, HTlc-DIC/PCL fibrous membranes can be used as an antinflammatory scaffold for tissue engineering.

Morphological and Dielectric Behavior of Carbon Nanotube-Ferroelectric Liquid Crystal Composite

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.67.167 ◽

2009 ◽

Vol 67 ◽

pp. 167-172 ◽

Cited By ~ 2

Author(s):

Deepika Sharma ◽

Sachin Tyagi ◽

K.K. Raina

Keyword(s):

Carbon Nanotubes ◽

Liquid Crystal ◽

Carbon Nanotube ◽

Phase Transformations ◽

Dielectric Behavior ◽

Scanning Calorimetry ◽

Crystal Material ◽

Liquid Crystal Material ◽

High Dielectric

The present study deals with the effect of dispersing Carbon Nano Tubes in Ferro-electric liquid crystal material. Carbon nanotube dispersed ferroelectric liquid crystals have high dielectric constant, fast switching response, large electro-optic coefficient which makes them ideal for memories, capacitors and display devices etc. An attempt has been made to understand the influence of carbon nanotubes on dielectric and morphological properties of ferro-electric liquid crystal. The effect of carbon nanotubes concentration on the transition temperature of ferro-electric liquid crystal is also studied. Hot Stage Microscope is used to investigate the texture and phase transformations in the composite. Differential Scanning Calorimetry also indicated the phase transformations. The results are compared with the original ferro-electric liquid crystal material which showed that the dielectric permittivity is increased to a great extent with the addition of carbon nanotubes.

Injectable in-situ Forming Depot Of Doxycycline Hyclate/α-Cyclodextrin Complex using PLGA for Periodontitis Treatment: Preparation, Charac-terization, and In-Vitro Evaluation

Current Drug Delivery ◽

10.2174/1567201817999201103195104 ◽

2020 ◽

Vol 17 ◽

Author(s):

Elham Khodaverdi ◽

Farhad Eisvand ◽

Mohammad Sina Nezami ◽

Seyedeh Nesa Rezaeian Shiadeh ◽

Hossein Kamali ◽

...

Keyword(s):

Complex Form ◽

Docking Studies ◽

Burst Release ◽

Cyclodextrin Complex ◽

Doxycycline Hyclate ◽

Scanning Calorimetry ◽

In Situ Forming

Background:: Doxycycline (DOX) is used in treating a bacterial infection, especially for periodontitis treatment. Objective: To reduce irritation of DOX for subgingival administration and increase the chemical stability and against enzy-matic, the complex of α-cyclodextrin with DOX was prepared and loaded into injectable in situ forming implant based on PLGA. Methods:: FTIR, molecular docking studies, X-ray diffraction, and differential scanning calorimetry was performed to char-acterize the DOX/α-cyclodextrin complex. Finally, the in-vitro drug release and modeling, morphological properties, and cellular cytotoxic effects were also evaluated. Results:: The stability of DOX was improved with complex than pure DOX. The main advantage of the complex is the al-most complete release (96.31 ± 2.56 %) of the drug within 14 days of the implant, whereas in the formulation containing the pure DOX and the physical mixture the DOX with α-cyclodextrin release is reached to 70.18 ± 3.61 % and 77.03 ± 3.56 %, respectively. This trend is due to elevate of DOX stability in the DOX/ α-cyclodextrin complex form within PLGA implant that confirmed by the results of stability. Conclusion:: Our results were indicative that the formulation containing DOX/α-cyclodextrin complex was biocompatible and sustained-release with minimum initial burst release.

Characterization of Nostoc muscorum NCCU-442 Derived Poly-3- hydroxybutyrate (PHB) and Polyethylene Glycol (PEG) Blends

The Natural Products Journal ◽

10.2174/2210315508666180810145127 ◽

2020 ◽

Vol 10 (3) ◽

pp. 200-207

Author(s):

Sabbir Ansari ◽

Tasneem Fatma

Keyword(s):

Thermal Properties ◽

Polyethylene Glycol ◽

Morphological Alteration ◽

Nostoc Muscorum ◽

Microbial Culture ◽

Polymer Science ◽

Mixed Microbial Culture ◽

Scanning Calorimetry ◽

Casting Technique

Background: Poly-3-hydroxybutyrate (PHB) has attracted much consideration as biodegradable biocompatible polymer. This thermoplastic polymer has comparable material properties to polypropylene. Materials with more valuable properties may result from blending, a common practice in polymer science. Objective: In this paper, blends of PHB (extracted from cyanobacterium Nostoc muscorum NCCU- 442 with polyethylene glycol (PEG) were investigated for their thermal, tensile, hydrophilic and biodegradation properties. Methods: Blends were prepared in different proportions of PHB/PEG viz. 100/0, 98/2, 95/5, 90/10, 80/20, and 70/30 (wt %) using solvent casting technique. Morphological properties were investigated by using Scanning Electron Microscopy (SEM). Differential scanning calorimetry and thermogravimetric analysis were done for thermal properties determination whereas the mechanical and hydrophilic properties of the blends were studied by means of an automated material testing system and contact angle analyser respectively. Biodegradability potential of the blended films was tested as percent weight loss by mixed microbial culture within 60 days. Results: The blends showed good misciblity between PEG and PHB, however increasing concentrations of plasticizer caused morphological alteration as evidenced by SEM micrographs. PEG addition (10 % and above) showed significant alternations in the thermal properties of the blends. Increase in the PEG content increased the elongation at break ratio i.e enhanced the required plasticity of PHB. Rate of microbial facilitated degradation of the blends was greater with increasing PEG concentrations. Conclusion: Blending with PEG increased the crucial polymeric properties of cyanobacterial PHB.

Stability and Influence of Storage Conditions on Nanofibrous Film Containing Tooth Whitening Agent

Pharmaceutics ◽

10.3390/pharmaceutics13040449 ◽

2021 ◽

Vol 13 (4) ◽

pp. 449

Author(s):

Siriporn Okonogi ◽

Adchareeya Kaewpinta ◽

Pisaisit Chaijareenont

Keyword(s):

Water Absorption ◽

Storage Condition ◽

Storage Conditions ◽

Scanning Calorimetry ◽

Adhesive Properties ◽

Tooth Whitening ◽

Long Term Storage ◽

Whitening Agent ◽

Nanofibrous Structure

Carbamide peroxide (CP), a tooth whitening agent, is chemically unstable. The present study explores stability enhancement of CP by loading in a nanofibrous film (CP-F) composed of polyvinyl alcohol/polyvinylpyrrolidone/silica mixture, using an electrospinning technique. Kept at a temperature range of 60–80 °C for 6 h, CP in CP-F showed significantly higher stability than that in a polymer solution and in water, respectively. Degradation of CP in CP-F could be described by the first order kinetics with the predicted half-life by the Arrhenius equation of approximately 6.52 years. Physicochemical properties of CP-F after long-term storage for 12 months at different temperatures and relative humidity (RH) were investigated using scanning electron microscopy, X-ray diffractometry, differential scanning calorimetry, and Fourier transform infrared spectroscopy. It was found that high temperature and high humidity (45 °C/75% RH) could enhance water absorption and destruction of the nanofibrous structure of CP-F. Interestingly, kept at 25 °C/30% RH, the nanofibrous structure of CP-F was not damaged, and exhibited no water absorption. Moreover, the remaining CP, the mechanical properties, and the adhesive properties of CP-F were not significantly changed in this storage condition. It is concluded that the developed CP-F and a suitable storage condition can significantly improve CP stability.

Rheological, Thermal, Superficial, and Morphological Properties of Thermoplastic Achira Starch Modified with Lactic Acid and Oleic Acid

Molecules ◽

10.3390/molecules24244433 ◽

2019 ◽

Vol 24 (24) ◽

pp. 4433 ◽

Cited By ~ 2

Author(s):

Carolina Caicedo ◽

Rocío Yaneli Aguirre Loredo ◽

Abril Fonseca García ◽

Omar Hernán Ossa ◽

Aldo Vázquez Arce ◽

...

Keyword(s):

Lactic Acid ◽

Oleic Acid ◽

Complex Viscosity ◽

Thermoplastic Starch ◽

Residual Energy ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Rheological Analysis ◽

Acid Agent

The modification of achira starch a thermoplastic biopolymer is shown. Glycerol and sorbitol, common plasticizers, were used in the molten state with organic acids such as oleic acid and lactic acid obtaining thermodynamically more stable products. The proportion of starch:plasticizer was 70:30, and the acid agent was added in portions from 3%, 6%, and 9% by weight. These mixtures were obtained in a torque rheometer for 10 min at 130 °C. The lactic acid managed to efficiently promote the gelatinization process by increasing the available polar sites towards the surface of the material; as a result, there were lower values in the contact angle, these results were corroborated with the analysis performed by differential scanning calorimetry and X-ray diffraction. The results derived from oscillatory rheological analysis had a viscous behavior in the thermoplastic starch samples and with the presence of acids; this behavior favors the transitions from viscous to elastic. The mixture of sorbitol or glycerol with lactic acid promoted lower values of the loss module, the storage module, and the complex viscosity, which means lower residual energy in the transition of the viscous state to the elastic state; this allows the compounds to be scaled to conventional polymer transformation processes.

GDC - Y 2 O 3 Oxide Based Two Phase Nanocomposite Electrolyte

Journal of Fuel Cell Science and Technology ◽

10.1115/1.4003634 ◽

2011 ◽

Vol 8 (4) ◽

Cited By ~ 6

Author(s):

Rizwan Raza ◽

Ghazanfar Abbas ◽

S. Khalid Imran ◽

Imran Patel ◽

Bin Zhu

Keyword(s):

Fuel Cell ◽

Ionic Conductivities ◽

Scanning Calorimetry ◽

Two Phase ◽

Composite Electrolyte ◽

Significant Performance ◽

Advanced Fuel ◽

Nanocomposite Electrolyte ◽

Scherrer Formula

Oxide based two phase composite electrolyte (Ce0.9Gd0.1O2–Y2O3) was synthesized by coprecipitation method. The nanocomposite electrolyte showed the significant performance of power density 785 mW cm−2 and higher conductivities at relatively low temperature 550°C. Ionic conductivities were measured with ac impedance spectroscopy and four-probe dc method. The structural and morphological properties of the prepared electrolyte were investigated by scanning electron microscope (SEM). The thermal stability was determined with differential scanning calorimetry. The particle size that was calculated with Scherrer formula, 15–20 nm, is in a good agreement with the SEM and X- ray diffraction results. The purpose of this study is to introduce the functional nanocomposite materials for advanced fuel cell technology to meet the challenges of solid oxide fuel cell.

Development and Characterization of pH-Dependent Cellulose Acetate Phthalate Nanofibers by Electrospinning Technique

Nanomaterials ◽

10.3390/nano11123202 ◽

2021 ◽

Vol 11 (12) ◽

pp. 3202

Author(s):

Gustavo Vidal-Romero ◽

Virginia Rocha-Pérez ◽

María L. Zambrano-Zaragoza ◽

Alicia Del Real ◽

Lizbeth Martínez-Acevedo ◽

...

Keyword(s):

Cellulose Acetate ◽

Polymer Concentration ◽

Process Efficiency ◽

Fickian Diffusion ◽

Solvent Mixtures ◽

Cellulose Acetate Phthalate ◽

Scanning Calorimetry ◽

Ph Dependent ◽

Release Profiles

The aim of this work was to obtain pH-dependent nanofibers with an electrospinning technique as a novel controlled release system for the treatment of periodontal disease (PD). Cellulose acetate phthalate (CAP) was selected as a pH-sensitive and antimicrobial polymer. The NF was optimized according to polymeric dispersion variables, polymer, and drug concentration, and characterized considering morphology, diameter, entrapment efficiency (EE), process efficiency (PE), thermal properties, and release profiles. Two solvent mixtures were tested, and CHX-CAP-NF prepared with acetone/ethanol at 12% w/v of the polymer showed a diameter size of 934 nm, a uniform morphology with 42% of EE, and 55% of PE. Meanwhile, CHX-CAP-NF prepared with acetone/methanol at 11% w/v of polymer had a diameter of 257 nm, discontinuous nanofiber morphology with 32% of EE, and 40% of PE. EE and PE were dependent on the polymer concentration and the drug used in the formulation. Studies of differential scanning calorimetry (DSC) showed that the drug was dispersed in the NF matrix. The release profiles of CHX from CHX-CAP-NF followed Fickian diffusion dependent on time (t0.43−0.45), suggesting a diffusion–erosion process and a matrix behavior. The NF developed could be employed as a novel drug delivery system in PD.

Piezoelectric Properties of Zinc Oxide/Iron Oxide filled Polyvinylidene fluoride Nanocomposite Fibers

10.21203/rs.3.rs-339520/v1 ◽

2021 ◽

Author(s):

Abdulrahman Mohmmed AlAhzm ◽

Maan Omar Alejli ◽

Deepalekshmi Ponnamma ◽

Yara Elgawady ◽

Mariam Al Ali Al-Maadeed

Keyword(s):

Zinc Oxide ◽

Iron Oxide ◽

Polyvinylidene Fluoride ◽

Output Voltage ◽

Mechanical Energy ◽

Scanning Calorimetry ◽

Power Sources ◽

Hybrid Nanomaterial ◽

Β Phase ◽

Nanocomposite Fibers

Abstract Piezoelectric nanogenerators (PENG) with flexible and simple design have pronounced significance in fabricating sustainable devices for self-powering electronics. This study demonstrates the fabrication of electrospun nanocomposite fibers from polyvinylidene fluoride (PVDF) filled Zinc Oxide (ZnO)/Iron Oxide (FeO) nanomaterials. The nanocomposite fiber based flexible PENG showed piezoelectric output voltage of 5.9 V when 3 wt.% of ZnO/FeO hybrid nanomaterial was introduced, which was 29.5 times higher than the neat PVDF. No apparent decline in output voltage was observed for almost 2000 seconds attributed to the outstanding durability. This higher piezoelectric output performance is correlated with the β-phase transformation studies from the Fourier transformation infrared spectroscopy and the crystallinity studies from the differential scanning calorimetry. Both these studies show respective enhancement of 3.79 and 2.16 % in the β-phase crystallinity values of PVDF-ZnO/FeO 3 wt.% composite. Higher dielectric constant value obtained for the same composite (3 times higher than the neat PVDF) confirms the increased energy storage efficiency as well. Thus the proposed soft and flexible PENG is a promising mechanical energy harvester, and its good dielectric properties reveals the ability to use this material as good power sources for wearable and flexible electronic devices.