scholarly journals Incorporation of Nanohybrid Films of Silica into Recycled Polystyrene Matrix

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Genoveva Hernández-Padrón ◽  
Domingo Rangel-Miranda ◽  
Gerardo Cedillo ◽  
Alejandra Blanco-Hernández
Keyword(s):  
Sol Gel ◽  
Textural Properties ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Glass Substrates ◽  
H Nmr ◽  
Sol Gel Process ◽  
Nmr Techniques ◽  
Polystyrene Waste ◽  
Sol Gel Synthesis

An alternative for the reutilization of polystyrene waste containers consisting in creating a hybrid material made of SiO2nanoparticles embedded in a matrix of recycled polystyrene (PSR) has been developed. Recycled polystyrene functionalized (PSRF) was used to influence the morphological and antifog properties by the sol-gel synthesis of nanohybrid silica. To this end, silica nanoparticles were produced from alkoxide precursors in the presence of recycled polystyrene. The functionalization of this polymeric matrix was with the purpose of uniting in situ carboxyl and silanol groups during the sol-gel process. In this way, opaque or transparent solid substrates can be obtained, with each of these endowed with optical conditions that depend on the amount of reactants employed to prepare each nanohybrid specimen. The nanohybrids were labelled as SiO2/PSR (HPSR) and SiO2/PSRF (HPSRF) and their properties were then compared to those of commercial polystyrene (PS). All the prepared samples were used for coating glass substrates. The hydrophobicity of the resultant coatings was determined through contact angle measurement. The nanohybrid materials were characterized by FT-IR and1H-NMR techniques. Additionally, TGA and SEM were employed to determine their thermal and textural properties.

Sol-gel synthesis of biocompatible silica-chitosan hybrids and hydrophobic coatings

2008 ◽  
Vol 23 (8) ◽  
pp. 2053-2060 ◽  
Author(s):  
S. Smitha ◽  
P. Shajesh ◽  
P. Mukundan ◽  
K.G.K. Warrier
Keyword(s):  
Condensation Reaction ◽  
Sol Gel ◽  
Visible Region ◽  
Reaction Medium ◽  
Optical Transmittance ◽  
Hydrophobic Coatings ◽  
Glass Substrates ◽  
Sol Gel Process ◽  
Sol Gel Synthesis

A new organic–inorganic hybrid synthesized through a sol-gel process starting from alkoxysilane and chitosan is reported. Functionalization of the hybrid was effected through in situ hydrolysis–condensation reaction of methyltrimethoxysilane (MTMS) and vinyltrimethoxysilane (VTMS) in the reaction medium. The process yields highly transparent and hydrophobic silica–chitosan hybrids. The hybrid gel was investigated with respect to chemical modification, thermal degradation, hydrophobicity, and transparency under the ultraviolet-visible region. The extent of hydrophobicity had been tailored by varying the precursor ratio. SiO2–chitosan–MTMS hybrids showed a higher thermal stability than SiO2–chitosan–VTMS (SCV) hybrids with respect to hydrophobicity. Condensation of silsesquioxanes generated from the hydrolysis of MTMS and VTMS over the silica-chitosan particles impart hydrophobicity to the hybrid. The coatings of functionalized SiO2–chitosan precursor sol on glass substrates showed nearly 100% optical transmittance in the visible region. The present hybrid material may find application in optics and other industries.

Fabrication of Super-Hydrophobic Membrane with Hydrophilic Polyethersulphone

2011 ◽  
Vol 396-398 ◽  
pp. 361-366
Author(s):  
Guang Fen Li ◽  
Xu Dong Sun ◽  
Yu Zhong Zhang
Keyword(s):  
Contact Angle ◽  
Sol Gel ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Hydrophobic Membrane ◽  
Sem Images ◽  
Simple Method ◽  
Membrane Surfaces ◽  
Sol Gel Process ◽  
Experimental Parameters

Here a simple method was developed to fabricate super-hydrophobic membrane with hydrophilic Polyethersulphone (PES) via a sol-gel process. The influences of experimental parameters i.e. the precursor treated time, the baking temperature of the membrane, and the fluorinated time on the hydrophobicity of the membranes were extensively investigated. The correspondent hydrophobicity was crosschecked by the contact angle measurement. For the optimum condition, the contact angle of the resulted super-hydrophobic membrane can be increased to 156°. The FTIR analysis confirmed that the membrane surfaces were covered by hydrophobic functional groups, which resulted in both higher surface roughness and higher heterogeneity, and therefore higher hydrophobicity. The micro/nano-meter crater-like protrusions on the membrane surfaces were observed from the images obtained from both AFM and SEM measurements. Moreover, the spongy holes and the finger-like holes were observed in cortex and intermediate layer respectively, from the cross-section of the SEM images.

Preparation of TiO2–SiO2 Hybrid Nanosols Coated Flame-Retardant Polyester Fabric Possessing Dual Contradictory Characteristics of Superhydrophobicity and Self Cleaning Ability

2020 ◽  
Vol 20 (3) ◽  
pp. 1780-1789 ◽  
Author(s):  
Priyanka Katiyar ◽  
Shraddha Mishra ◽  
Anurag Srivastava ◽  
N. Eswara Prasad
Keyword(s):  
Electron Microscopy ◽  
Contact Angle ◽  
Flame Retardant ◽  
Protective Clothing ◽  
Sol Gel ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Water Contact ◽  
Vis Spectroscopy ◽  
Self Cleaning

TiO2, SiO2 and their hybrid nanocoatings are prepared on inherent flame retardant textile substrates from titanium(IV)iso-proproxide (TTIP) and tetraethoxysilane (TEOS) precursors using a sol–gel process followed by hydrothermal treatment. The coated samples are further functionalized by hexadecyltrimethoxysilane (HDTMS) to impart superhydrophobicity. Sample characterization of the nanosols, nanoparticles and coated samples are investigated using, X-ray diffractometer, transmission electron microscopy, scanning electron microscopy, UV-Vis spectroscopy, contact angle measurement. Stain degradation test under mild UV irradiation shows almost 54% degradation of coffee stain within 4 hours measured by Spectrophotometer. UV-Vis Absorption Spectroscopy demonstrates complete degradation of methyl orange colorant within 3 hours. Hybrid nanosol coated and HDTMS modified inherent flame retardant polyester surfaces show apparent water contact angle as ~145°, which is much closer to proximity of superhydrophobic surfaces. Thus, the novelty of present work is, by using sol–gel technique, a bi-functional textile surface has been developed which qualifies the very specific requirements of protective clothing like self-cleaning property (imparted by TiO2 nanoparticles) and superhydrophobicity (imparted by SiO2 nanoparticles and further surface modification by HDTMS), which are entirely contradictory in nature, in a single fabric itself. Thus developed textile surfaces also possess the other attributes of protective clothing like flame retardancy and air permeability.

Bicontinuous nanodisc and nanospherical titania materials prepared by sol-gel process in reverse microemulsion

2012 ◽  
Vol 66 (3) ◽  
Author(s):  
Khaled Haouemi ◽  
Fathi Touati ◽  
Néji Gharbi
Keyword(s):  
Sol Gel ◽  
Textural Properties ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tio2 Particles ◽  
Sol Gel Process ◽  
Bet Method ◽  
Reverse Microemulsions ◽  
Different Shapes

AbstractTiO2 nanoparticles with different shapes and sizes were synthesised by the sol-gel route in Water/Brij78/Hexane reverse microemulsions. The aqueous cores of these microemulsions were used as nanoreactors to control sol-gel reactions. We studied the effect of water/surfactant mole ratio (W 0) on the morphology, and textural properties of the final products. The materials thus obtained were characterised by different techniques. Thermogravimetric and differential thermal analysis (TG-DTA) was used to study the thermal behaviour of the products and X-ray diffraction (XRD) to identify the crystalline phases. The morphological and textural properties of the products were determined by scattering electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method, respectively. We also studied the influence of thermal treatment on the structure and size of the TiO2 particles. The effect of W 0 on the anatase-rutile phase transition temperature was investigated.

Sol–gel synthesis of PZT thin films on FTO glass substrates for electro-optic devices

2019 ◽  
Vol 93 (3) ◽  
pp. 623-632
Author(s):  
Ali Shoghi ◽  
Hossein Abdizadeh ◽  
Amid Shakeri ◽  
Mohammad Reza Golobostanfard
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Pzt Thin Films ◽  
Glass Substrates ◽  
Electro Optic ◽  
Sol Gel Synthesis ◽  
Fto Glass

scholarly journals Influence of the Framework Topology on the Reactivity of Chiral Pyrrolidine Units Inserted in Different Porous Organosilicas

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 654
Author(s):  
Sebastián Llopis ◽  
Alexandra Velty ◽  
Urbano Díaz
Keyword(s):  
Sol Gel ◽  
Textural Properties ◽  
Michael Adduct ◽  
Structural Framework ◽  
Ordered Mesoporous ◽  
Sol Gel Process ◽  
Variable Content ◽  
Hybrid Solids ◽  
The Michael Addition ◽  
Level Order

Three families of organosiliceous materials with different structuration level, order, and textural properties (non-ordered, M41S, and SBA-15 type materials) were prepared incorporating in their structural framework chiral pyrrolidine units with variable content. Likewise, non-ordered mesoporous hybrid solids were obtained through a sol-gel process in a fluoride medium, while M41S and SBA-15 type materials were obtained through micellar routes in the presence of long-chain neutral surfactants or block copolymers. Thanks to appropriate characterization studies and catalytic tests for the Michael addition between butyraldehyde and β-nitrostyrene, we showed how the void shapes and sizes present in the structure of hybrid materials control the diffusion of reactants and products, as well as confine transition states and reactive intermediates. The best catalytic results, considering activity and enantioselectivity, were achieved in the presence of a non-ordered material, NOH-Pyr-5%, which exhibited the highest Brunauer-Emmett-Teller (BET) area, with a 96% yield and a 82% ee for the Michael adduct.

Transparent semiconductor zinc oxide thin films deposited on glass substrates by sol–gel process

2010 ◽  
Vol 36 (6) ◽  
pp. 1791-1795 ◽  
Author(s):  
Chien-Yie Tsay ◽  
Kai-Shiung Fan ◽  
Yu-Wu Wang ◽  
Chi-Jung Chang ◽  
Yung-Kuan Tseng ◽  
...  
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Sol Gel ◽  
Oxide Thin Films ◽  
Glass Substrates ◽  
Sol Gel Process ◽  
Transparent Semiconductor

Effect of Sintering Time on the Phase Composition in PFN Ceramics Prepared by Sol-Gel Process

2009 ◽  
Vol 409 ◽  
pp. 317-321 ◽  
Author(s):  
Helena Bruncková ◽  
Ľubomír Medvecký ◽  
Ján Mihalik
Keyword(s):  
Perovskite Phase ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Molar Ratio ◽  
Sintering Time ◽  
Sol Gel Process ◽  
Sol Gel Synthesis ◽  
Spherical Grains ◽  
Bimodal Grain Size ◽  
Iron Niobate

Lead iron niobate Pb(Fe0.5Nb0.5)O3 (PFN) ceramics were prepared using sol-gel synthesis by mixing acetates Pb and Fe with Nb-ethylene glycol-tartarate (Pechini) complex at 80°C, calcination of gels at 600°C and sintering at 1150°C for various times. The metastable pyrochlore phase Pb3Nb4O13 in stoichiometric precursor was partially decomposed to perovskite phase Pb(Fe0.5Nb0.5)O3 in ceramics sintered at temperature of 1150°C for 2, 4 and 6 hours. Excess of Pb in molar ratio (Pb:Fe:Nb = 1.2:0.5:0.5) caused the increase of the content of the perovskite phase (~50 vol.%) in nonstoichiometric PFN ceramics sintered at 1150°C for 6 hours while the decrease in perovskite phase content was found in stoichiometric PFN ceramics (~16 vol.%). In microstructures of PFN ceramics sintered at 1150°C for different times, the bimodal grain size distribution was observed with small spherical grains of perovskite phase and larger octahedral grains of pyrochlore phase. EDX analysis confirm that complex types of pyrochlore phases that differ in iron content were present in ceramics.

scholarly journals Formation of nanoscopic CaF2via a fluorolytic sol–gel process for antireflective coatings

2015 ◽  
Vol 3 (8) ◽  
pp. 1716-1723 ◽  
Author(s):  
Alexander Rehmer ◽  
Kerstin Scheurell ◽  
Erhard Kemnitz
Keyword(s):  
Sol Gel ◽  
Nano Particles ◽  
Antireflective Coatings ◽  
Sol Gel Process ◽  
Sol Gel Synthesis ◽  
First Time

For the first time transparent antireflective CaF2-coatings were prepared from clear CaF2-sols obtained via the fluorolytic sol–gel synthesis and containing homo-dispersed CaF2 nano-particles.

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