scholarly journals Role of Organically-Modified Zn-Ti Layered Double Hydroxides in Poly(Butylene Succinate-Co-Adipate) Composites: Enhanced Material Properties and Photodegradation Protection

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2181
Author(s):  
Jie-Mao Wang ◽  
Hao Wang ◽  
Erh-Chiang Chen ◽  
Yun-Ju Chen ◽  
Tzong-Ming Wu
Keyword(s):  
Gel Permeation Chromatography ◽  
Spectroscopy Analysis ◽  
Exchange Method ◽  
Butylene Succinate ◽  
Transmission Electron ◽  
Organically Modified ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Microscopy Images

In this research, the effects of Zn-Ti layered double hydroxide (Zn-Ti LDH) as a UV-protection additive, which was added to the poly(butylene succinate-co-adipate) (PBSA) matrix, were investigated. Stearic acid was used to increase the hydrophobicity of Zn-Ti LDH via ion-exchange method. Transmission electron microscopy images of PBSA composites showed that modified Zn-Ti LDH (m-LDH) well-dispersed in the polymer matrix. Due to the effect of heterogeneous nucleation, the crystallization temperature of the composite increased to 52.9 °C, and the accompanying crystallinity increased to 31.0% with the addition of 1 wt% m-LDH. The additional m-LDH into PBSA copolymer matrix significantly enhanced the storage modulus, as compared to pure PBSA. Gel permeation chromatography and Fourier transform infrared spectroscopy analysis confirmed that the addition of m-LDH can reduce the photodegradation of PBSA.

Physical - Chemical Issues of Cephalosporin Intercalated Nanoparticles for Life - Threatening Infections Treatment

2001 ◽  
Vol 71 (3) ◽  
pp. 342-349
Author(s):  
Lucian Eva ◽  
Letitia Doina Duceac ◽  
Liviu Stafie ◽  
Constantin Marcu ◽  
Geta Mitrea ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Advanced Characterization ◽  
Generation Cephalosporin ◽  
Fourth Generation ◽  
Exchange Method ◽  
Physico Chemical ◽  
Life Threatening ◽  
Double Hydroxide ◽  
Double Hydroxides

The fourth generation cephalosporin antibacterial agent, cefepime, was loaded into layered double hydroxides for enhancing antibiotic efficiency, reducing side effects, as well as achieving the sustained release property. The intercalation of antibiotic into the inter-gallery of ZnAl-layered double hydroxide (LDH) was carried out using ion exchange method, by this constituting a nano-sized organic-inorganic hybrid material for a controlled release novel formulation. Although cefepime is a broad spectrum antibiotic, it has various adverse effects and a significant degradation rate. Thus, the preparation and physico-chemical characterization of nanomaterials able to intercalate this drug is an important study for medical and pharmaceutical field. The antibiotic inclusion into LDHs nanostructure was confirmed by advanced characterization techniques and the release profile of cefepime was analysed with the respect to pH of the simulated media.

scholarly journals Silver Orthophosphate Immobilized on Flaky Layered Double Hydroxides as the Visible-Light-Driven Photocatalysts

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Xianlu Cui ◽  
Yaogang Li ◽  
Qinghong Zhang ◽  
Hongzhi Wang
Keyword(s):  
Visible Light ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Visible Light Driven ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Acid Red G

Flaky layered double hydroxide (FLDH) was prepared by the reconstruction of its oxide in alkali solution. The composites with FLDH/Ag3PO4mass ratios at 1.6 : 1 and 3 : 1 were fabricated by the coprecipitation method. The powders were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscope, and UV-vis diffuse reflectance spectroscopy. The results indicated that the well-distributed Ag3PO4in a fine crystallite size was formed on the surface of FLDH. The photocatalytic activities of the Ag3PO4immobilized on FLDH were significantly enhanced for the degradation of acid red G under visible light irradiation compared to bare Ag3PO4. The composite with the FLDH/Ag3PO4mass ratio of 3 : 1 showed a higher photocatalytic efficiency.

scholarly journals Enzymatic Degradation of Acrylic Acid-Grafted Poly(butylene succinate-co-terephthalate) Nanocomposites Fabricated Using Heat Pressing and Freeze-Drying Techniques

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 376 ◽  
Author(s):  
Sheng-Hsiang Lin ◽  
Hsiang-Ting Wang ◽  
Jie-Mao Wang ◽  
Tzong-Ming Wu
Keyword(s):  
Acrylic Acid ◽  
Freeze Drying ◽  
Crystallization Rate ◽  
X Ray Diffraction ◽  
Butylene Succinate ◽  
Covalent Bonds ◽  
Polymer Backbone ◽  
Transmission Electron ◽  
Degradation Rates ◽  
Organically Modified

Biodegradable acrylic acid-grafted poly(butylene succinate-co-terephthalate) (g-PBST)/organically modified layered zinc phenylphosphonate (m-PPZn) nanocomposites were effectively fabricated containing covalent bonds between the g-PBST and m-PPZn. The results of wide-angle X-ray diffraction and transmission electron microscopy revealed that the morphology of the g-PBST/m-PPZn nanocomposites contained a mixture of partially exfoliated or intercalated conformations. The isothermal crystallization behavior of the nanocomposites showed that the half-time for crystallization of 5 wt % g-PBST/m-PPZn nanocomposites was less than 1 wt % g-PBST/m-PPZn nanocomposites. This finding reveals that increasing the loading of m-PPZn can increase the crystallization rate of nanocomposites. Degradation tests of g-PBST/m-PPZn nanocomposites fabricated using the heat pressing and the freeze-drying process were performed by lipase from Pseudomonas sp. The degradation rates of g-PBST-50/m-PPZn nanocomposites were significantly lower than those of g-PBST-70/m-PPZn nanocomposites. The g-PBST-50 degraded more slowly due to the higher quantity of aromatic group and increased stiffness of the polymer backbone. The degradation rate of the freeze-drying specimens contained a more extremely porous conformation compared to those fabricated using the heat pressing process.

Preparation and characterization of polystyrene-MgAl layered double hydroxide nanocomposites using bulk polymerization

2016 ◽  
Vol 36 (7) ◽  
pp. 681-693 ◽  
Author(s):  
Hadja Benaddi ◽  
Djafer Benachour ◽  
Yves Grohens
Keyword(s):  
Flame Retardants ◽  
Bulk Polymerization ◽  
Basal Spacing ◽  
Cone Calorimetry ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Fire Properties ◽  
Double Hydroxide ◽  
Double Hydroxides

Abstract Polymer/mineral filler nanocomposites are more and more used for diverse applications. As mineral fillers, layered double hydroxides (LDHs) present a great advantage as flame retardants from an environmental point a view (reduction of smoke and toxic gases). This article deals with the use of LDH as flame retardants as compared to montmorillonite (MMT). In situ bulk polymerization of styrene was carried out in the presence of MgAl LDH modified with dodecyl sulfate (DDS) and dodecylbenzene sulfonate (DBS) surfactants. LDH concentrations used were lower than 10 wt.%. X-ray diffraction analysis of the LDH-styrene suspensions revealed the monomer intercalation into the DDS-LDH galleries and a slight decrease in the DBS-LDH basal spacing. Transmission electron microscopy analysis showed that the polymerization occurred outside the DBS-LDH galleries, leading to exfoliation of the layers on the outer surface of LDH platelets. DDS-LDH particles were trapped in the PS polymer. The thermal stability effect was observed for all LDH nanocomposites by thermogravimetric analysis. Cone calorimetry measurements revealed that only the DBS-LDH nanofiller resulted in a reduction of the peak heat released rate (PHHR) and a decrease of smoke released. DBS-LDH/PS exhibited fire properties close to those of clay-PS nanocomposite at 7 wt.% montmorillonite. The PHRR reduction remained small and the total heat release rate constant at 7 wt.% DBS-LDH loading.

Discrete angle rotations of Bi nanoparticles embedded in a Ga matrix

Open Physics ◽  
2010 ◽  
Vol 8 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Avraham Be’er ◽  
Richard Kofman ◽  
Yossi Lereah
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Time Resolved ◽  
Transmission Electron ◽  
The Difference ◽  
First Time ◽  
Microscopy Images ◽  
Bi Nanoparticles

AbstractSpontaneous instabilities of nanoparticles are known to be influenced by the temperature, and strongly depend on the particle size. However, it is not clear what is the role of the surrounding material that is in contact with the particle. Here we report on the difference between spontaneous rotations of Bi nanoparticles embedded in amorphous SiO and those embedded in liquid Ga. The phenomenon was studied quantitatively by time resolved transmission electron microscopy using Fourier Transform analysis of highresolution electron microscopy images. While rotations of Bi nanoparticles embedded in amorphous SiO occur by all angles, the rotations of Bi nanoparticles embedded in liquid Ga occur by discrete angles. Our results point quantitatively, for the first time, to the role and importance of the contacting surrounding surface during the rotation of nanoparticles.

scholarly journals Synthesis, Characterization and Photocatalytic Performance of Calcined ZnCr-Layered Double Hydroxides

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3051
Author(s):  
Somia Djelloul Bencherif ◽  
Juan Jesús Gallardo ◽  
Iván Carrillo-Berdugo ◽  
Abdellah Bahmani ◽  
Javier Navas
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Textural Properties ◽  
Operational Parameters ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Crystal Violet Dye ◽  
Double Hydroxide ◽  
Double Hydroxides

The development of new materials for performing photocatalytic processes to remove contaminants is an interesting and important research line due to the ever-increasing number of contaminants on our planet. In this sense, we developed a layered double hydroxide material based on Zn and Cr, which was transformed into the corresponding oxide by heat treatment at 500 °C. Both materials were widely characterized for their elemental composition, and structural, morphological, optical and textural properties using several experimental techniques such as x-ray diffraction, x-ray photoelectron spectroscopy, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, UV-vis spectroscopy and physisorption techniques. In addition, the photocatalytic activity of both materials was analysed. The calcined one showed interesting photocatalytic activity in photodegradation tests using crystal violet dye. The operational parameters for the photocatalytic process using the calcined material were optimised, considering the pH, the initial concentration of the dye, the catalyst load, and the regeneration of the catalyst. The catalyst showed good photocatalytic activity, reaching a degradation of 100% in the optimised conditions and showing good performance after five photodegradation cycles.

Double glass transitions in exfoliated poly(methyl methacrylate)/organically modified MgAl layered double hydroxide nanocomposites

RSC Advances ◽  
2016 ◽  
Vol 6 (104) ◽  
pp. 101941-101947 ◽  
Author(s):  
Xiaohai Li ◽  
Lin Chen ◽  
Qiulong Li ◽  
Jinjin Zhang ◽  
Zheng Su ◽  
...  
Keyword(s):  
Methyl Methacrylate ◽  
Layered Double Hydroxide ◽  
Polymer Matrix ◽  
Layered Double Hydroxides ◽  
Interfacial Layer ◽  
Layered Material ◽  
Glass Transitions ◽  
Organically Modified ◽  
Double Hydroxide ◽  
Double Hydroxides

PMMA chains were confined at a layered material (organically modified MgAl layered double hydroxides) surface, which formed the interfacial layer between nanoparticles and the polymer matrix.

Ultrathin Colloidal PbS/CdS Core/Shell Nanosheets

MRS Advances ◽  
2017 ◽  
Vol 2 (60) ◽  
pp. 3685-3690
Author(s):  
Simeen Khan ◽  
Zhoufeng Jiang ◽  
Shashini M Premathilka ◽  
Jianjun Hu ◽  
Andrey Voevodin ◽  
...  
Keyword(s):  
Cross Sections ◽  
Energy Gap ◽  
Blue Shift ◽  
Core Shell ◽  
Accurate Analysis ◽  
Exchange Method ◽  
Transmission Electron ◽  
The Relationship ◽  
Sharp Interfaces ◽  
Microscopy Images

ABSTRACTEmissive PbS/CdS core/shell nanosheets are synthesized using a cation-exchange method. A significant blue-shift of the photoluminescence is observed, indicating a stronger quantum confinement in the PbS core as its thickness is reduced to eight atomic layers. High resolution transmission-electron-microscopy images of the cross-sections of the core/shell nanosheets show atomically sharp interfaces between PbS and CdS. Accurate analysis of the thickness of each layer reveals the relationship between the energy-gap and the thickness in the extremely one-dimensionally confined nanostructure.

scholarly journals Zein-layered hydroxide biohybrids: strategies of synthesis and characterization

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 825
Author(s):  
Alcântara ◽  
Darder ◽  
Aranda ◽  
Ruiz-Hitzky
Keyword(s):  
Electron Microscopy ◽  
Basic Medium ◽  
Basic Study ◽  
Corn Protein ◽  
Transmission Electron ◽  
Interlayer Region ◽  
Angle Spinning ◽  
Synthetic Approaches ◽  
Double Hydroxide ◽  
Double Hydroxides

This work constitutes a basic study about the first exploration on the preparation of biohybrids based on the corn protein zein and layered metal hydroxides, such as layered double hydroxides (LDH) and layered single hydroxides (LSHs). For this purpose, MgAl layered double hydroxide and the Co2(OH)3 layered single hydroxide were selected as hosts, and various synthetic approaches were explored to achieve the formation of the zein-layered hydroxide biohybrids, profiting from the presence of negatively charged groups in zein in basic medium. Zein-based layered hydroxide biohybrids were characterized by diverse physicochemical techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis/differential thermal analysis (TG/DTA), solid state 13C cross-polarization magical angle spinning nuclear magnetic resonance (CP-MAS NMR), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), etc., which suggest that the different synthesis procedures employed and the anion located in the interlayer region of the inorganic host material seem to have a strong influence on the final features of the biohybrids, resulting in mixed, single intercalated, or highly exfoliated intercalated phases. Thus, the resulting biohybrids based on zein and layered hydroxides could have interest in applications in biomedicine, biosensing, materials for electronic devices, catalysis, and photocatalysis.

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