scholarly journals Characteristic of Hybrid Cellulose-Amino Functionalized POSS-Silica Nanocomposite and Antimicrobial Activity

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Sivalingam Ramesh ◽  
Jaehwan Kim ◽  
Joo-Hyung Kim
Keyword(s):  
Coupling Agent ◽  
High Performance ◽  
Pathogenic Bacteria ◽  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Morphological Properties ◽  
Regenerated Cellulose ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Covalent Crosslinking ◽  
Silica Hybrid

Recently, cellulose has much attention as an emerging renewable nanomaterial which holds promising properties having unique piezoelectricity, insulating, and biodegradable nature for various applications. Also, the modified properties of cellulose by appropriate chemical modifications in various functional groups with outstanding properties or significantly improved physical, chemical, biological, and electronic properties will widen the way for it to be utilized in different usages. Therefore, in this paper, cellulose-functionalized polyhedral oligomeric silsesquioxanes (POSS) based materials were considered an important class of high-performance hybrid nanocomposite materials. To functionalize the regenerated cellulose, amino functionalized POSS material was synthesized via sol-gel covalent crosslinking process in presence of amino coupling agent. In this reaction, tetraethoxsilane (TEOS) andγ-aminopropyltriethoxy silane (γ-APTES) as coupling agent for metal precursors were selected. The chemical structure of cellulose-amine functionalized bonding and covalent crosslinking hybrids was confirmed by FTIR and1H NMR spectral analysis. From the TEM results, well-dispersed hybrid cellulose-functionalized POSS-silica composites are observed. The resulting cellulose-POSS-silica hybrid nanocomposites materials provided significantly improved the optical transparency, and thermal and morphological properties to compare the cellulose-silica hybrid materials. Further, antimicrobial test against pathogenic bacteria was carried out.

Synthesis and Properties of Cellulose-Functionalized POSS-SiO2/TiO2 Hybrid Composites

2015 ◽  
Vol 15 (10) ◽  
pp. 8048-8054 ◽  
Author(s):  
Gwang-Wook Hong ◽  
Sivalingam Ramesh ◽  
Joo-Hyung Kim ◽  
Hyeon-Ju Kim ◽  
Ho-Saeng Lee
Keyword(s):  
Electron Microscopy ◽  
Hybrid Material ◽  
Pathogenic Bacteria ◽  
Hybrid Composites ◽  
Sol Gel ◽  
Biological Properties ◽  
Hybrid Nanocomposites ◽  
Titania Nanoparticles ◽  
Morphological Properties ◽  
Host Matrix

The mechanical, thermal, optical, electrical and morphological properties of cellulose, an excellent natural biomaterial, can be improved by organic-inorganic hybrid composite methods. Based on the pristine properties of cellulose, the preparation of cellulose-metal oxide hybrid nanocomposites using a dispersion process of nanoparticles into the cellulose host matrix by traditionalmethods, has limitations. Recently, the functionalized cellulose-polymer-basedmaterials were considered to be an important class of high-performance materials, providing the synthesis of various functional hybrid nanocomposites using a sol-gel method. Transparent cellulose-POSS-amine-silica/titania hybrids were prepared by an in-situ sol-gel process in the presence of γ-aminopropyltrimethoxylsilane (γ-APTES). The methodology involves the formation of covalent bonding between the cellulose- POSS amine and SiO2/TiO2 hybrid nanocomposite material. An analysis of the synthesized hybrid material by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, differential thermal calorimetry, scanning electron microscopy, and transmission electron microscopy indicated that the silica/titania nanoparticles were bonded covalently and dispersed uniformly into the cellulose-POSS amine matrix. In addition, biological properties of the cellulose-POSSsilica/titania hybrid material were examined using an antimicrobial test against pathogenic bacteria, such as Bacillus cereus (F481072) and E.coli (ATCC35150) for the bacterial effect.

Polyamide-6,6/in situ silica hybrid nanocomposites by sol–gel technique: synthesis, characterization and properties

Polymer ◽  
2005 ◽  
Vol 46 (10) ◽  
pp. 3343-3354 ◽  
Author(s):  
Rajatendu Sengupta ◽  
Abhijit Bandyopadhyay ◽  
Sunil Sabharwal ◽  
Tapan K. Chaki ◽  
Anil K. Bhowmick
Keyword(s):  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
In Situ Silica ◽  
Gel Technique ◽  
Silica Hybrid

scholarly journals Light-driven oxygen evolution from water oxidation with immobilised TiO2 engineered for high performance

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria J. Sampaio ◽  
Zhipeng Yu ◽  
Joana C. Lopes ◽  
Pedro B. Tavares ◽  
Cláudia G. Silva ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Water Oxidation ◽  
High Performance ◽  
Operation Mode ◽  
Sol Gel ◽  
Morphological Properties ◽  
Adsorption Sites ◽  
Oxygen Defects ◽  
Uv Led ◽  
Apparent Quantum Efficiency

AbstractCalcination treatments in the range of 500–900 °C of TiO2 synthesised by the sol–gel resulted in materials with variable physicochemical (i.e., optical, specific surface area, crystallite size and crystalline phase) and morphological properties. The photocatalytic performance of the prepared materials was evaluated in the oxygen evolution reaction (OER) following UV-LED irradiation of aqueous solutions containing iron ions as sacrificial electron acceptors. The highest activity for water oxidation was obtained with the photocatalyst thermally treated at 700 °C (TiO2-700). Photocatalysts with larger anatase to rutile ratio of the crystalline phases and higher surface density of oxygen vacancies (defects) displayed the best performance in OER. The oxygen defects at the photocatalyst surface have proven to be responsible for the enhanced photoactivity, acting as important active adsorption sites for water oxidation. Seeking technological application, water oxidation was accomplished by immobilising the photocatalyst with the highest OER rate measured under the established batch conditions (TiO2-700). Experiments operating under continuous mode revealed a remarkable efficiency for oxygen production, exceeding 12% of the apparent quantum efficiency (AQE) at 384 nm (UV-LED system) compared to the batch operation mode.

Solution Rheology of Poly(vinyl alcohol)/Silica Hybrid Nanocomposites

2005 ◽  
Vol 13 (5) ◽  
pp. 429-442
Author(s):  
Abhijit Bandyopadhyay ◽  
Mousumi De Sarkar ◽  
Anil K. Bhowmick
Keyword(s):  
Vinyl Alcohol ◽  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Solution Viscosity ◽  
Poly Vinyl Alcohol ◽  
Silica Nanocomposites ◽  
Teos Concentration ◽  
Ph Range ◽  
Increasing Temperature ◽  
Silica Hybrid

The solution behavior of polymer/silica hybrid nanocomposites was investigated using a Brookfield viscometer. The nanocomposites were prepared using the sol-gel technique with tetraethoxysilane (TEOS) as the precursor for silica. The sol-gel reaction was carried out in the pH range of 1.0-2.0, which was maintained by the addition of concentrated HCl. Poly (vinyl alcohol) (PVA)/silica nanocomposites demonstrated a bigger rise in solution viscosity after continuous measurement for five days than either- acrylic rubber (ACM)/silica or epoxidised natural rubber (ENR)/silica nanocomposites. Detailed investigation of the PVA/silica system indicated that it exhibited Newtonian behaviour when the solutions contained (5 or 7.5 wt% of PVA,) even when increasing the TEOS concentration to 50 wt%, although at one particular TEOS concentration (10 wt%), the nanocomposite was pseudoplastic when the concentration of PVA was increased to 10 wt%. The reinforcement factor [Formula: see text] for those PVA/silica hybrid nanocomposites containing 5 wt% of PVA deviated strongly from the Guth-Smallwood prediction. Instead they obeyed a relationship of the type ηmax = η0(1 + aϕb), where a = 4.45 and b = 0.38, calculated for this system. The viscosity decreased with increasing temperature for both PVA and the representative nanocomposite with 30 wt% TEOS (PVA30), although the activation energy for flow of the nanocomposite did not vary to a great extent.

Synthesis of Novel Fluorosiloxane Polymer/Silica Hybrid Nanocomposites and Superhydrophobic Cotton Surface from it

2011 ◽  
Vol 480-481 ◽  
pp. 681-686 ◽  
Author(s):  
Wei Xu ◽  
Qiu Feng An ◽  
Wei Xu
Keyword(s):  
Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Bulk Polymerization ◽  
Hybrid Nanocomposites ◽  
Hydrophobic Property ◽  
Thermogravimetric Analyzer ◽  
Static Contact ◽  
Micro Morphology ◽  
Silica Hybrid

A fluorine-silicon polymer (PFAMS) with pendant perfluoroalkyl and reactive epoxy groups was firstly synthesized by bulk polymerization (Si-H additional reaction) of polymethyltrifluoropropylsiloxane (PFHMS), allylpolyoxyethylene ether (AGE) and perfluorooctyl ethylene (PFOE). Then amino-functionalized nano silica (KH550-SiO2) was prepared via sol-gel method by 3-aminopropyltriethoxylsilane (KH550) and tetraethyl orthosilicate (TEOS). Finally novel fluorosiloxane polymer/silica hybrid nanocomposites (PFAMS-SiO2) were fabricated through graft copolymerization method by the above two chemicals, PFAMS and KH550-SiO2 and super-hydrophobic cotton fabric was also constructed with contact angle of water on its surface 160.91° through immersing-padding-baking processes. Chemical structure, thermal performance, micro-morphology and hydrophobic property of the hybrid materials and film were investigated by Fourier Transform Infrared Spectrum (FT-IR), Thermogravimetric Analyzer (TGA), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and Static contact angle analyzer, respectively. Results show that a hydrophobic film and many lotus-leaf-like micro-nano scale tubercles are coated on the surface of cotton fabrics.

Synthesis of Polymer/Silica Hybrid Nanocomposites Prepared by the Sol-Gel Method

2007 ◽  
pp. 1129-1132
Author(s):  
Ji Kyung Kim ◽  
Seong Soo Park ◽  
Bong Ki Ryu ◽  
Hong Chae Park ◽  
Seog Young Yoon
Keyword(s):  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Gel Method ◽  
Sol Gel Method ◽  
Silica Hybrid

scholarly journals The Effect of Silica Loading on the Performance and Morphology of Polyimide–Silica Hybrid Membrane

2017 ◽  
Vol 14 (1) ◽  
Author(s):  
N. S. A. Bakar ◽  
S. A. Hashemifard ◽  
A. Mustafa
Keyword(s):  
Gas Separation ◽  
Sol Gel ◽  
Gas Permeation ◽  
Hybrid Membrane ◽  
Morphological Properties ◽  
Hybrid Membranes ◽  
Separation Processes ◽  
Polyimide Membrane ◽  
Silica Sols ◽  
Silica Hybrid

The performance of silica-polyimide hybrid membranes has been investigated for gas separation processes. The dope solution consisted of polyimide resin dissolved in NMP and silica sols at various weight percentages. The silica sols were prepared using a sol–gel process and the flat–sheet silica–polyimide hybrid membranes were cast using an immersion precipitation technique. The effects of silica sols loading on the gas transport properties of polyimide hybrid membranes and the correlation of morphology changes in the membrane structure and molecular orientation were studied. Polyimide hybrid membranes with silica sols loading ranging from 0 to 50 wt% were tested on gas permeation performance with single gas of O2, N2, CH4 and CO2. The gas permeation results showed that the hybrid membranes with 20 wt% to 25 wt% silica loading exhibited higher selectivity than the pure polyimide membrane. Morphological properties and molecular orientations of the silica–polyimide hybrid membranes were also studied using SEM and FTIR, respectively. The SEM and FTIR results confirmed that the 20 and 25 wt% of silica loading was the ideal composition of polyimide–silica hybrid membrane for gas separation.

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