Polysiloxanes modified with aromatic diamines interconnecting with silica network

2010 ◽  
Vol 45 (6) ◽  
pp. 621-630 ◽  
Author(s):  
Mihaela Alexandru ◽  
Carmen Racles ◽  
Maria Cazacu ◽  
Alexandra Nistor ◽  
Ana-Maria Macsim
Keyword(s):  
Sol Gel ◽  
Aromatic Diamine ◽  
Thermal Transitions ◽  
Dynamic Vapor Sorption ◽  
Silica Network ◽  
Scanning Calorimetry ◽  
Aromatic Diamines ◽  
Force Microscopy ◽  
H Nmr ◽  
Atomic Force

Polydimethylsiloxane-α,ω-diols with different contents of pendant chloromethyl groups were reacted with an aromatic diamine (3,3′-dimethoxybenzidine) when cross-linking occurred. The reactions were performed in silica — generating sol— gel system; so two interconnected networks (silica and cross-linked polydimethylsiloxane) were formed. The resulting structures were investigated by FT-IR and 1H-NMR spectroscopies. Differential scanning calorimetry was used to emphasize the thermal transitions of the resulted materials and the water sorption capacity was investigated by dynamic vapor sorption, the obtained values being influenced by the amount of polar groups. Atomic force microscopy was used to evaluate the morphology and surface topography in dry as well as in swollen state in water and heptane.

scholarly journals Synthesis and Characterization of Polycarbonate Copolymers Containing Benzoyl Groups on the Side Chain for Scratch Resistance

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Hohyoun Jang ◽  
Jaeseong Ha ◽  
Jiho Yoo ◽  
Jaeseung Pyo ◽  
Kunyoung Choi ◽  
...  
Keyword(s):  
Methylene Chloride ◽  
Water Drop ◽  
Scratch Resistance ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
H Nmr ◽  
Chemical Structures ◽  
Atomic Force ◽  
Rearrangement Reaction ◽  
Surface Morphologies

The purpose of this study was to enhance the scratch resistance of polycarbonate copolymer by using 3,3′-dibenzoyl-4,4′-dihydroxybiphenyl (DBHP) monomer, containing benzoyl moieties on the ortho positions. DBHP monomer was synthesized from 4,4′-dihydroxybiphenyl and benzoyl chloride, followed by the Friedel-Craft rearrangement reaction with AlCl3. The polymerizations were conducted following the low-temperature procedure, which is carried out in methylene chloride by using triphosgene, triethylamine, bisphenol-A, and DBHP. The chemical structures of the polycarbonate copolymers were confirmed by1H-NMR. The thermal properties of copolymers were investigated by thermogravimetric analysis and differential scanning calorimetry, and also surface morphologies were assessed by atomic force microscopy. The scratch resistance of homopolymer film (100 μm) changed from 6B to 1B, and the contact angle of a sessile water drop onto the homopolymer film also increased.

scholarly journals Preparation of (Pb,Ba)TiO3 powders and highly oriented thin films by a sol-gel process

2004 ◽  
Vol 19 (5) ◽  
pp. 1492-1498 ◽  
Author(s):  
Stacey W. Boland ◽  
Suresh C. Pillai ◽  
Wein-Duo Yang ◽  
Sossina M. Haile
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Chelating Agent ◽  
Titanium Isopropoxide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Molar Ratios ◽  
Atomic Force ◽  
Sol Gel Process

Solid solution Pb1-xBaxTiO3, with particular emphasis on Pb0.5Ba0.5TiO3, was prepared using a sol-gel process incorporating lead acetate trihydrate, barium acetate, and titanium isopropoxide as precursors, acetylacetone (2,4 pentanedione) as a chelating agent, and ethylene glycol as a solvent. The synthesis procedure was optimized by systematically varying acetylacetone: Ti and H2O:Ti molar ratios and calcination temperature. The resulting effects on sol and powder properties were studied using thermogravimetric analysis/differential scanning calorimetry, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and x-ray diffraction (XRD). Crystallization of the perovskite structure occurred at a temperature as low as 450 °C. Thin films were prepared by spin coating on (100) MgO. Pyrolysis temperature and heating rate were varied, and the resultant film properties investigated using field-emission scanning electron microscopy, atomic force microscopy, and XRD. Under optimized conditions, highly oriented films were obtained at a crystallization temperature of 600 °C.

Effect of cooling induced crystallization upon the properties of segmented thermoplastic polyurethanes

2017 ◽  
Vol 37 (5) ◽  
pp. 471-480 ◽  
Author(s):  
Daniel Ramirez ◽  
Juliana Nanclares ◽  
Marisa Spontón ◽  
Mara Polo ◽  
Diana Estenoz ◽  
...  
Keyword(s):  
Hard Segment ◽  
Chain Extender ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Thermoplastic Polyurethanes ◽  
Dsc Measurements ◽  
Atomic Force ◽  
Hard Segment Content ◽  
Induced Crystallization

Abstract An investigation on the cooling-induced crystallization in three thermoplastic polyurethanes based on MDI, PTMG, and 1.4-BD as chain extender with different hard segment content is reported. Thermal transitions were determined using differential scanning calorimetry (DSC) measurements at different cooling rates, and thermal stability was studied by thermogravimetric analysis. Changes in Raman spectra were useful to correlate the thermal transitions with changes in the morphology of the polymers. The dissimilarity in the composition gave different rheological behavior in the molten state, indicated by the temperature dependence of the viscosity. The mechanical properties and the crystallinity was influenced not only by the cooling rate but also by the hard segment content. Thermoplastic polyurethanes with more hard segment content formed more crystalline hard domains as evidenced by the DSC and atomic force microscopy results.

Nano Composite Membranes of Sulfonated Poly (Ether Ketone)/ Poly (Ether Sulfone) Copolymer and SiO2 for Fuel Cell Application

2007 ◽  
Vol 544-545 ◽  
pp. 1013-1016
Author(s):  
Hae Suck Park ◽  
Dong Hwan Suh ◽  
Dong Hun Lee ◽  
Whan Gi Kim
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
Composite Membranes ◽  
Scanning Calorimetry ◽  
Nano Composite ◽  
Force Microscopy ◽  
Atomic Force ◽  
Fuel Cell Application ◽  
Sol Gel Process ◽  
Ether Ketone

Novel bisphenol-based wholly aromatic poly(ether ketone)/poly(ether sulfone) copolymers containing pendant sulfonate groups were prepared by direct aromatic nucleophilic substitution polycondensation of 4,4-difluoro-3,3’-disodiumsulfonylbenzophenone (40mol% of bisphenol), difluorophenylsulfone and bisphenol A. Organic-inorganic composite membranes were obtained by mixing organic polymers with hydrophilic SiO2 (ca. 20nm) obtained by sol-gel process. The physic-chemical properties of these composite membranes were studied by thermogravimetry analysis(TGA), differential scanning calorimetry (DSC) and transform infrared(FTIR) spectroscopy. Scanning electron microscopy (SEM) and atomic Force microscopy (AFM) were used to observe the surface of membrances. The proton conductivity as a function of temperature decreased as SiO2 content increased, but water uptake increased. The membranes were shown all requisite properties; IEC (1.5meq./g), thermal stablity (Tg= 185°C), and low affinity towards methanol (1.5x10-7 - 4.3x10-7 cm2/S).

scholarly journals Preparation, Thermal, and Thermo-Mechanical Characterization of Polymeric Blends Based on Di(meth)acrylate Monomers

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 878
Author(s):  
Krystyna Wnuczek ◽  
Andrzej Puszka ◽  
Łukasz Klapiszewski ◽  
Beata Podkościelna
Keyword(s):  
Mechanical Analysis ◽  
Attenuated Total Reflection ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Chemical Structures ◽  
Atomic Force ◽  
Polymeric Blends ◽  
Ft Ir ◽  
Acrylate Monomers ◽  
Synthesized Materials

This study presents the preparation and the thermo-mechanical characteristics of polymeric blends based on di(meth)acrylates monomers. Bisphenol A glycerolate diacrylate (BPA.GDA) or ethylene glycol dimethacrylate (EGDMA) were used as crosslinking monomers. Methyl methacrylate (MMA) was used as an active solvent in both copolymerization approaches. Commercial polycarbonate (PC) was used as a modifying soluble additive. The preparation of blends and method of polymerization by using UV initiator (Irqacure® 651) was proposed. Two parallel sets of MMA-based materials were obtained. The first included more harmless linear hydrocarbons (EGDMA + MMA), whereas the second included the usually used aromatic copolymers (BPA.GDA + MMA). The influence of different amounts of PC on the physicochemical properties was discussed in detail. Chemical structures of the copolymers were confirmed by attenuated total reflection–Fourier transform infrared (ATR/FT-IR) spectroscopy. Thermo-mechanical properties of the synthesized materials were investigated by means of differential scanning calorimetry (DSC), thermogravimetric (TG/DTG) analyses, and dynamic mechanical analysis (DMA). The hardness of the obtained materials was also tested. In order to evaluate the surface of the materials, their images were obtained with the use of atomic force microscopy (AFM).

Sol-Gel Derived Titaniajormosil Composite Thin Films For Optical Waveguide Applications

1999 ◽  
Vol 576 ◽  
Author(s):  
Wenxiu Que ◽  
Y. Zhou ◽  
Y. L. Lam ◽  
Y. C. Chan ◽  
S. D. Cheng ◽  
...  
Keyword(s):  
Sol Gel ◽  
Single Layer ◽  
Titanium Content ◽  
Gravimetric Analysis ◽  
Force Microscopy ◽  
Free Film ◽  
Free Silica ◽  
Atomic Force ◽  
Bonding Properties ◽  
Single Layer Film

ABSTRACTWe report the preparation of sol-gel waveguide films based on a newly developed recipe to incorporate organic molecules into the inorganic sol-gel glass matrix. The film was derived from a sol that has a higher titanium content in an organically modified silane (ORMOSIL), namely, ÿ-Glycidoxypropyltrimethoxysilane. We have shown that using spin-coating and low temperature baking, a single coating layer can have a thickness of more than 1.5 μm. When such a single layer film is deposited on a microscope glass slide or a piece of silicon with a buffercladding layer, it is able to support the guiding of optical waves. We have characterized the film using scanning electron microscopy, atomic force microscopy, X-ray diffractometry, thermal gravimetric analysis. differential thermal analysis and Fourier transform infrared spectroscopy and have studied the properties of the waveguide film, including the microstructural properties. the chemical bonding properties, and the optical properties. Based on these experimental results, we found that a heat-treatment at a temperature slightly below 200°C is necessary to attain a dense pore-free film. It has also been noted that a purely inorganic and crack-free silica-titania film can be obtained after baking the titania-ORMOSIL composite film at 500°C or higher.

Determination of the Physical Properties of Oil Sands Components using Scanning Probe Microscopy

2015 ◽  
Vol 1754 ◽  
pp. 69-74
Author(s):  
Ravi Gaikwad ◽  
Tinu Abraham ◽  
Aharnish Hande ◽  
Fatemeh Bakhtiari ◽  
Siddhartha Das ◽  
...  
Keyword(s):  
Oil Sands ◽  
Structural Changes ◽  
Rational Approach ◽  
Kelvin Probe ◽  
Scanning Calorimetry ◽  
Probe Microscopy ◽  
Kelvin Probe Microscopy ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTAtomic force microscopy is employed to study the structural changes in the morphology and physical characteristics of asphaltene aggregates as a function of temperature. The exotic fractal structure obtained by evaporation-driven asphaltene aggregates shows an interesting dynamics for a large range of temperatures from 25°C to 80°C. The changes in the topography, surface potential and adhesion are unnoticeable until 70°C. However, a significant change in the dynamics and material properties is displayed in the range of 70°C - 80°C, during which the aspahltene aggregates acquire ‘liquid-like’ mobility and fuse together. This behaviour is attributed to the transition from the pure amorphous phase to a crystalline liquid phase which occurs at approximately 70°C as shown by using Differential Scanning Calorimetry (DSC). Additionally, the charged nature of asphaltenes and bitumen is also explored using kelvin probe microscopy. Such observations can lead to the development of a rational approach to the fundamental understanding of asphaltene aggregation dynamics and may help in devising novel techniques for the handling and separation of asphaltene aggregates using dielectrophoretic methods.

Infrared Characterization of PMMA-SiO2 Hybrid Glasses Obtained by Sol-Gel Process

2010 ◽  
Vol 1278 ◽  
Author(s):  
L.L. Díaz-Flores ◽  
A. S. López Rodríguez ◽  
P. SifuentesGallardo ◽  
M.A. Hernàndez Rivera ◽  
M.a Garnica Romo ◽  
...  
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
Hybrid Coatings ◽  
Force Microscopy ◽  
Air Atmosphere ◽  
Atomic Force ◽  
Sol Gel Process ◽  
Traditional Process ◽  
And Chemical Properties

AbstractThis work is about the production of hybrid coatings of the system SiO2-PMMA (PMMA, polymethylmethacrylate). These materials have interesting mechanical and chemical properties useful for anticorrosive and wear resistance applications. SiO2-PMMA hybrids were obtained by the sol-gel traditional process, using tetraethylorthosilicate (TEOS) and methylmethacrylate (MMA) by Aldrich Co, as starting reagents. The SiO2:PMMA ratio was varied from 0:1 to about 1:1 at air atmosphere deposition. The coatings were obtained on acrylic sheets and silicon wafers. A diversity of coatings with chemical composition ranging from SiO2 and PMMA to obtain the SiO2-PMMA hybrids were obtained. Infrared (IR) and atomic force microscopy (AFM), were performed to determinate structural and morphological behavior.

scholarly journals Preparation of TiO2 nanorods by Sol–Gel template method and measured its photo- catalytic activity for degradation of methyl orange

2019 ◽  
Vol 13 (26) ◽  
pp. 171-177
Author(s):  
Ban M. Al-Shabander
Keyword(s):  
Methyl Orange ◽  
Sol Gel ◽  
Tio2 Nanorods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Photo Catalytic Activity ◽  
Atomic Force ◽  
Degradation Of Methyl Orange ◽  
Titanium Dioxide Nanorods

Titanium dioxide nanorods have been prepared by sol-gel templatemethod. The structural and surface morphology of the TiO2 nanorods wasinvestigated by X-ray diffraction (XRD) and atomic force microscopy(AFM), it was found that the nanorods produced were anatase TiO2 phase.The photocatalytic activity of the TiO2 nanorods was evaluated by thephoto degradation of methyl orange (MO). The relatively higherdegradation efficiency for MO (D%=78.2) was obtained after 6h of exposedto UV irradiation.

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