Preparation of PAA/PEO blend nanofibers via electrospinning process

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Zahed Shami ◽  
Naser Sharifi-Sanjani
Keyword(s):  
Intermolecular Interactions ◽  
Average Diameter ◽  
Sem Analysis ◽  
Electrospinning Process ◽  
Hydroxyl Groups ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Dsc Measurements ◽  
Free Hydroxyl ◽  
Poly Ethylene

AbstractThe novel poly(acrylic acid)/poly(ethylene oxide) (PAA/PEO) blend nanofibers at 100/0, 80/20, 50/50, 20/80 and 0/100 weight ratios were obtained via electrospinning process. Intermolecular interactions and compatibility of blend fibers were studied by Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC). It was found that the free-hydroxyl groups, the bonded hydrogen hydroxyl groups and the carbonyl groups absorption bands in the electrospun PAA/PEO fibers shifted with the increase in PEO percentage in the blend. DSC measurements showed the melting point, the glass transition temperature, the melting enthalpy and the crystallinity percentage of pure polymer nanofibers were different compared with blend nanofibers. The results suggested that intermolecular interactions occurred in the electrospun PAA/PEO nanofibers. These interactions made PAA/PEO blends miscible at above-mentioned weight ratios. Additionally, the morphology and the average fiber diameter were investigated using scanning electron microscope (SEM) analysis, which indicated beadless fibers with diameter range of 110 to 280 nm. It was observed that the uniform fibers with the smaller average diameter were obtained in PAA/PEO blends containing PAA dominant content. Finally, the SEM results suggested that the formation of pure PAA nanofibers with concentration of 5 Wt. % would not occur. Whereas, in the same concentration, pure PEO and PAA/PEO blend nanofibers with no bead defects were obtained.

scholarly journals Velcrand Functionalized Polyethylene

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 902
Author(s):  
Jonathan Tellers ◽  
Jérôme Vachon ◽  
Maria Soliman ◽  
Enrico Dalcanale ◽  
Roberta Pinalli
Keyword(s):  
Barrier Properties ◽  
Isocyanate Group ◽  
Hydroxyl Groups ◽  
Oxygen Barrier ◽  
Specific Class ◽  
Solution Casting ◽  
Slow Evaporation ◽  
Scanning Calorimetry ◽  
Free Hydroxyl ◽  
Poly Ethylene

Velcrands are a specific class of cavitands whose complementary surfaces induce self-dimerization. The insertion of a velcrand as physical cross-linking unit into a polymer is reported. To this purpose, the velcrand was functionalized at the lower rim with an isocyanate group. The functional velcrand was reacted with poly (ethylene-co-(2-hydroxethylmethacrylate)) (PE-HEMA), a polymer equipped with free hydroxyl groups suitable for reaction with the isocyanate group. The obtained functionalized polymer was characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR), proving the introduction of velcraplexes in the polymer. Films with varying amounts of velcrands were obtained by solution casting and slow evaporation, testifying the processability of the functionalized polymers. The obtained films were used to measure the oxygen barrier properties of the functionalized material.

Toughening Modification of Poly(butylene terephthalate)/Polycarbonate Blends by Poly(ethylene-co-octene)

2005 ◽  
Vol 13 (4) ◽  
pp. 385-394
Author(s):  
Huiyu Bai ◽  
Yong Zhang ◽  
Yinxi Zhang ◽  
Xiangfu Zhang ◽  
Wen Zhou
Keyword(s):  
Average Diameter ◽  
Melt Blending ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Bisphenol A Polycarbonate ◽  
Elongation At Break ◽  
Butylene Terephthalate ◽  
Twin Screw ◽  
Poly Ethylene ◽  
The Impact

New toughened poly(butylene terephthalate) (PBT)/bisphenol A polycarbonate (PC) blends were obtained by melt blending with commercial poly(ethylene-co-octene) copolymer (POE), varying the POE content up to 10 wt%, in a twin screw extruder, followed by injection moulding. The influence of POE on the properties of the PBT/PC blends was investigated in terms of mechanical testing, dynamic mechanical thermal (DMTA) analysis, differential scanning calorimetry (DSC), and scanning electronic microscopy (SEM). The results showed that addition of POE led to remarkable increases in the impact strength, elongation at break and Vicat temperature, and a reduction in the tensile strength and flexural properties of PBT/PC blends. The morphology of the blends was observed using SEM and the average diameter of the dispersed phase was determined by image analysis. The critical inter-particle distance for PBT/PC was determined.

scholarly journals Preparation and Characterization of Poly(ethylene-co-vinyl alcohol)/poly(ε-caprolactone) Blend for Bioscaffolding Applications

2020 ◽  
Vol 21 (16) ◽  
pp. 5881 ◽  
Author(s):  
Abdulaziz Ali Alghamdi ◽  
Hussain Alattas ◽  
Waseem Sharaf Saeed ◽  
Abdel-Basit Al-Odayni ◽  
Ali Alrahlah ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Vinyl Alcohol ◽  
Polymeric Materials ◽  
In Vitro Cytotoxicity ◽  
Hydroxyl Groups ◽  
Scanning Calorimetry ◽  
Reduced Pressure ◽  
Static Contact ◽  
Poly Ethylene

In order to improve the cell adhesion on poly(ε-caprolactone) (PCL) scaffolds, poly(ethylene-co-vinyl alcohol) (E-VAL) which has hydroxyl groups capable of developing hydrogen bonds with celling was blended with this polymer. To reach this goal, a series of E-VAL/PCL blends with different compositions were prepared by the solvent casting method. The miscibility of the polymer blend was proved by differential scanning calorimetry and Fourier-transform infrared spectroscopy spectrometry. Furthermore, the mechanical properties of the polymer blends were assessed in their wet state by dynamic mechanical analysis. The surfaces wettability of blends and their components were examined through static contact angle measurements. The pore interconnections in the resulted scaffolds were achieved by the incorporation of naphthalene microparticles which were used as porogen and then removed in its gas state by sublimation under reduced pressure. The presence of pores interconnected inside the polymeric materials and their surface morphologies was examined by scanning electron microscopy. The in-vitro cytotoxicity and cell adhesion on the prepared materials were examined by an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay.

scholarly journals Inkjet Printable and Self-Curable Disperse Dyes/P(St-BA-MAA) Nanosphere Inks for Both Hydrophilic and Hydrophobic Fabrics

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1402 ◽  
Author(s):  
Yawei Song ◽  
Kuanjun Fang ◽  
Yanfei Ren ◽  
Zhiyuan Tang ◽  
Rongqing Wang ◽  
...  
Keyword(s):  
Fiber Surface ◽  
Spherical Shape ◽  
Average Diameter ◽  
Film Coating ◽  
Water Soluble ◽  
Disperse Dyes ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Long Term Stability ◽  
Dsc Measurements

Low-water-soluble disperse dyes possess a broad color gamut and good durability, but they need chemical or physical modification before being used in inks and can only be applied to several kinds of hydrophobic fabrics. In this work, disperse dyes/P(St-BA-MAA) nanospheres (known as DPN) absorbed by sodium nitrilotriacetate (known as NTA@DPN) were prepared and applied into ink formulations, which exhibited high dye fixation, long-term stability and self-curable ability without addition of any binder. Transmission electron microscopy (TEM) images showed the nanospheres have homogeneous core-shell spherical shape and the average diameter increased by 20.6 nm after coloration. X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), and differential scanning calorimetry (DSC) measurements illustrated the interaction between dyes and nanospheres and indicated that the colored nanospheres contained both dye molecules and crystalline dyes. The Zeta potential and particle size measurements demonstrated that the dispersion stability was improved when sodium nitrilotriacetate (NTA) was absorbed onto DPN. The rheological behavior of the NTA@DPN inks was Newtonian and desired droplet formation was achieved at the viscosity of 4.23 mPa·s. Both hydrophilic cotton and hydrophobic polyester fabrics were cationic modified before used, which had an excellent image quality and desired rubbing fastness after inkjet printing. Scanning electron microscope (SEM) images showed NTA@DPN formed stable deposits on the surface of modified fibers and could self-cure to form continuous film coating on the fiber surface after being baked at 150 °C without addition of any binder.

Synthesis of Hydrophilic Two-Photon Absorptive Fullerene-diphenylaminoflourene Dyads for Molecular Self-assembly in Water

2004 ◽  
Vol 846 ◽  
Author(s):  
Sarika Verma ◽  
Tanya Hauck ◽  
Prashant A. Padmawar ◽  
Taizoon Canteenwala ◽  
Long Y. Chiang ◽  
...  
Keyword(s):  
Intermolecular Interactions ◽  
Electron Micrographs ◽  
Self Assembly ◽  
Molecular Aggregation ◽  
Absorption Bands ◽  
Two Photon ◽  
Amphiphilic Molecules ◽  
Transmission Electron ◽  
Poly Ethylene ◽  
Water Transmission

ABSTRACTSynthetic conditions for the preparation of amphiphilic two-photon absorptive poly(ethylene glycolated) diphenylaminofluorene[60]fullerene conjugates C60(>DPAF-PEG6) were investigated. UV-vis spectra of C60(>DPAF-PEG6) collected at the concentration of 1.0 × 10–5 M in water showed absorption bands with a slight red shift, broadened, and in a less intensity as compared with those of the bands obtained in CHCl3. These features are important characteristics of C60(>DPAF-PEG6) molecular aggregation in water. Transmission electron micrographs taken at the concentration of 1.0 × 10–5 M in H2O clearly displayed images of spherical aggregates in a diameter of 200–400 nm. That substantiated high hydrophobic intermolecular interactions between these amphiphilic molecules for assemblies in water.

scholarly journals Layer-By-Layer Assembled, Amphiphilic And Antibacterial Hybrid Electrospun Mat Made From Polypropylene And Chitosan Fibers

2021 ◽  
Author(s):  
Gokhan Acik ◽  
Burcu Acik ◽  
E. Agel
Keyword(s):  
Antibacterial Activity ◽  
Sem Analysis ◽  
Electrospinning Process ◽  
Layer By Layer ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
E Coli ◽  
Ft Ir ◽  
Dsc Analyses ◽  
First Time

Abstract In this study, hybrid fiber mat (HFPP-CS) consisting of both chlorinated polypropylene and chitosan fibers (FPP-Cl and FCS) is obtained by assembling layer-by-layer (LBL) for the first time using electrospinning process. Morphological, wettability, structural and thermal properties of HFPP-CS are investigated in detail by Scanning electron microscopy (SEM), water contact angle (WCA) measurement, fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analyses, respectively, comparing with FPP-Cl and FCS. Furthermore, the antibacterial activity of all samples was evaluated against to gram positive Staphylococcus aureus (S. aureus) and gram negative Escherichia coli (E. coli) bacteria. SEM analysis proves to HFPP-CS has a circular and smooth morphology and also comprises of microscale FPP-Cl and nanoscale FCS layers. The incorporation of nano-FCS layer on micro-FPP-Cl layer leads to diminution in the hydrophobicity, but enhancement in the thermostability and glass transition temperature of the resulting fiber mat. The antibacterial activity results show that HFPP-CS has inhibition effect against to S. aureus and E. coli. In general, it is anticipated that the prepared amphiphilic and antibacterial HFPP-CS can be employed as potential biomaterial for a variety of bioengineering applications.

scholarly journals Structuring of High-Fine Mineral Particles to Prevent Wind and Water Erosion

2021 ◽  
Author(s):  
O. N. Dabizha ◽  
D. V. Bespolitov ◽  
N. A. Konovalova ◽  
P. P. Pankov
Keyword(s):  
Polymer Solution ◽  
Water Erosion ◽  
Hydroxyl Groups ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Intermolecular Hydrogen Bonds ◽  
Mineral Particles ◽  
Hydration Layers ◽  
Wind And Water Erosion

The results of the study of the mechanism of structuring highly dispersed mineral particles by dust-pressing polymer solution StabOL are presented, using the example of overburden rocks of the Taseevsky, Baleisky and Kamensky quarries (Transbaikal Territory). Mineral and polymer-mineral samples were studied by differential scanning calorimetry, thermogravimetry, and infrared spectroscopy. The formation of intermolecular hydrogen bonds is confirmed by the shift of the absorption bands of the stretching vibrations of hydroxyl groups in the infrared spectra of polymer-mineral samples towards lower frequencies and a significant increase in the intensities of these absorption bands. It was found that structuring of mineral particles during their treatment with a polymer solution occurs through the formation of organomineral complexes as a result of intercalation, exfoliation (stratification) and adsorption of polymers. The important role of hydration layers and clay minerals in this process has been revealed.

Spectroscopic study of Na–TCNQ in a poly(ethylene oxide) matrix (TCNQ = 7, 7′, 8, and 8′ tetracyanoquinodimethane)

1997 ◽  
Vol 12 (5) ◽  
pp. 1405-1409 ◽  
Author(s):  
A. Arena ◽  
G. Di Marco ◽  
M. Lanza ◽  
S. Patané ◽  
G. Saitta
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrical Transport ◽  
Near Infrared ◽  
Infrared Range ◽  
Metallic State ◽  
Infrared Transmission ◽  
Scanning Calorimetry ◽  
Amorphous Phases ◽  
Dsc Measurements ◽  
Poly Ethylene

X-ray Photoelectron Spectroscopy (XPS) and optical studies have been performed on P(EO)n –NaI–TCNQ (n = 1, 10) systems, obtained by means of a solid state reaction technique. The electron spectroscopy, the absorption in the ultraviolet visible near infrared range, and the infrared transmission findings allow us to conclude that the interaction among the polymer, the iodide, and the electron acceptor molecule results in the formation of the ion-radical salt Na–TCNQ and in the oxidation of I− to the metallic state. The presence within the examined specimens of crystalline and amorphous phases has been confirmed by the results of Differential Scanning Calorimetry (DSC) measurements. The optical, electronic, and thermal properties of the P(EO)n–NaI–TCNQ mixtures have then been correlated to the results of preliminary ac electrical transport investigations.

Nevirapine Pharmaceutical Cocrystal: Design, Development and Formulation

2019 ◽  
Vol 9 (3) ◽  
pp. 240-247
Author(s):  
Prabhakar Panzade ◽  
Priyanka Somani ◽  
Pavan Rathi
Keyword(s):  
Dosage Form ◽  
In Vitro Dissolution ◽  
Soluble Form ◽  
Ir Absorption ◽  
Stoichiometric Ratio ◽  
Design Development ◽  
Formulation Development ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Pharmaceutical Cocrystal

Background and Objective: The top approach to deliver poorly soluble drugs is the use of a highly soluble form. The present study was conducted to enhance the solubility and dissolution of a poorly aqueous soluble drug nevirapine via a pharmaceutical cocrystal. Another objective of the study was to check the potential of the nevirapine cocrystal in the dosage form. Methods: A neat and liquid assisted grinding method was employed to prepare nevirapine cocrystals in a 1:1 and 1:2 stoichiometric ratio of drug:coformer by screening various coformers. The prepared cocrystals were preliminary investigated for melting point and saturation solubility. The selected cocrystal was further confirmed by Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC), and Xray Powder Diffraction (XRPD). Further, the cocrystal was subjected to in vitro dissolution study and formulation development. Results: The cocrystal of Nevirapine (NVP) with Para-Amino Benzoic Acid (PABA) coformer prepared by neat grinding in 1:2 ratio exhibited greater solubility. The shifts in IR absorption bands, alterations in DSC thermogram, and distinct XRPD pattern showed the formation of the NVP-PABA cocrystal. Dissolution of NVP-PABA cocrystal enhanced by 38% in 0.1N HCl. Immediate release tablets of NVP-PABA cocrystal exhibited better drug release and less disintegration time. Conclusion: A remarkable increase in the solubility and dissolution of NVP was obtained through the cocrystal with PABA. The cocrystal also showed great potential in the dosage form which may provide future direction for other drugs.

The synthesis and structure of silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complexes

1986 ◽  
Vol 51 (7) ◽  
pp. 1430-1438 ◽  
Author(s):  
Alena Reissová ◽  
Zdeněk Bastl ◽  
Martin Čapka
Keyword(s):  
Free Surface ◽  
Hydroxyl Groups ◽  
Titanium Complex ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Free Hydroxyl ◽  
Cyclopentadienyl Anion

The title complexes have been obtained by functionalization of silica with cyclopentadienylsilanes of the type Rx(CH3)3 - xSi(CH2)nC5H5 (x = 1-3, n = 0, 1, 3), trimethylsilylation of free surface hydroxyl groups, transformation of the bonded cyclopentadienyl group to the cyclopentadienyl anion, followed by coordination of (h5-cyclopentadienyl)trichlorotitanium. The effects of single steps of the above immobilization on texture of the support, the number of free hydroxyl groups, the coverage of the surface by cyclopentadienyl groups and the degree of their utilization in anchoring the titanium complex have been investigated. ESCA study has shown that the above anchoring leads to formation of the silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complex.

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