Structural, Thermal, and Thermomechanical Behaviors of Phenolic-Inorganic Hybrid Composites

2000 ◽  
Vol 628 ◽  
Author(s):  
Samuel Amanuel ◽  
Vivak M. Malhotra
Keyword(s):  
Hybrid Composites ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Dynamic Mechanical Analyzer ◽  
Scanning Calorimetry ◽  
Inorganic Hybrid ◽  
Phenolic Polymer ◽  
Frictional Materials ◽  
Gel Technique

ABSTRACTIn pursuit of our goal of forming organic-inorganic hybrid frictional materials, we produced two types of composites, i.e., conventional and hybrid. We formed conventional composites by dispersing fly ash, montmorillonite clay, or pre-formed nano-sized silica particles in phenolic matrix. Hybrid composites were fabricated from sol-gel technique using tetramethylor-thosilicate-phenolic mixtures. We subjected our samples to X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), in-situ transmission-Fourier transform infrared (ISTA-FTIR), and dynamic mechanical analyzer (DMA) measurements at 40°C < T < 310°C. Our results suggested that the curing behavior of the phenolic polymer was affected by the concentration of the silica and hybrid composites manifested mechanical properties, which were substantially different from that of conventional composites.

Epoxidized Natural Rubber / Silica Nanoscale Organic-Inorganic Hybrid Composites Prepared by Sol-Gel Technique

2004 ◽  
Vol 77 (5) ◽  
pp. 830-846 ◽  
Author(s):  
Abhijit Bandyopadhyay ◽  
Mousumi De Sarkar ◽  
Anil K. Bhowmick
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Hybrid Composites ◽  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Dicumyl Peroxide ◽  
Inorganic Hybrid ◽  
Gel Technique ◽  
Rubber Phase

Abstract Epoxidized natural rubber (ENR) / silica organic-inorganic hybrid nanocomposites were prepared by using a sol-gel technique. Tetraethoxysilane was used as the precursor for the in-situ generation of silica. The choice of ENR as a matrix was made because of its polar nature which can interact with the in-situ generated silica. The sol-gel reaction was carried out at room temperature by dissolving the rubber in tetrahydrofuran solvent using hydrochloric acid as the catalyst. The resultant composite films appeared transparent up to 50 wt% of tetraethoxysilane loading. Dispersion of the discrete silica particles having dimensions of 15 – 100 nm was observed through transmission electron microscope. Scanning electron microscopic studies did not produce any evidence for formation of silica network within the bulk of the composite. Infrared spectroscopic studies indicated the occurrence of chemical interaction within the rubber /silica organic-inorganic interfaces which was further supported by the insolubility of the respective samples in tetrahydrofuran under the ambient conditions. Mechanical reinforcement within the hybrid nanocomposites, both at high and low temperature regions, was demonstrated through dynamic mechanical analysis. The composites exhibited superior tensile strength and tensile moduli compared to the gum rubber samples. Further reinforcement was noticed when the rubber phase in the nanocomposites was cured with either benzoyl peroxide or dicumyl peroxide. The dicumyl peroxide cured hybrid composites displayed 112% improvement in tensile strength over the control crosslinked rubber sample, probably due to synergisms of nanosilica reinforcement and crosslinking of the rubber phase in the hybrids.

scholarly journals Improvement of the optical and photocatalytic properties of ZnAl2O4: 1% La3+, x% Pb2+ nanoparticles synthesized by citrate sol-gel route

2021 ◽  
Author(s):  
Hichem Filali ◽  
Nahman Boukheit ◽  
Rafika Bouhroum ◽  
Wassila Chekirou ◽  
Ahcène Karaali
Keyword(s):  
Raman Spectroscopy ◽  
Single Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Constant Amount ◽  
Pure Zinc ◽  
Characterization Methods ◽  
X Ray ◽  
Gel Technique

Abstract Samples of pure zinc aluminate (ZnAl2O4) and doped both with lead (Pb2+) at different ratios (0, 0.5, 1, 1.5, 2 and 2.5% mol) and a constant amount of lanthanum (La: 1% mol), were prepared by the citrate sol-gel technique, and then annealed at 900°C for 2h. In order to study the structural, optical and thermal properties; different characterization methods were used, such as: powder X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), differential scanning calorimetry (DSC), TGA, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The Analyzes by XRD revealed the presence of the cubic single phase ZnAl2O4 for all samples, with a crystallites size between 19 and 25 nm. These results were confirmed using FTIR, Raman spectroscopy and SEM. Also, photocatalytic study for different samples of ZnAl2O4 shows that they can be used like as photocatalyst and good adsorbents for degradation of Hexamethyl crystallized violet dye in aqueous solution.

Preparation and Damping Capacities of the NiTiSMA/FC Composites

2010 ◽  
Vol 97-101 ◽  
pp. 1601-1606 ◽  
Author(s):  
Qing Suo Liu ◽  
Cui Min Lu ◽  
Xu Ma ◽  
X.M. Lu ◽  
X.Y. Gao
Keyword(s):  
Sol Gel ◽  
Ferroelectric Ceramics ◽  
Niti Shape Memory Alloy ◽  
X Ray Diffraction ◽  
Dynamic Mechanical Analyzer ◽  
Pure Perovskite Structure ◽  
X Ray ◽  
Ceramic Film ◽  
Better Than

NiTiSMA/FC composites have been prepared by depositing ferroelectric ceramics films on NiTi shape memory alloy substrate with the sol-gel method. Heterojunction structure of the composites has been characterized by using X-ray diffraction and scanning electron microscope. The differences of the damping capacities between NiTiSMA/FC composites and NiTiSMA substrates have been tested by the Dynamic Mechanical Analyzer. The results show pure perovskite structure could be obtained in the FC films part of NiTiSMA/FC composites sintered at 650oC. The transitional TiO2 layer produced in-situ by the oxidation of the surface of the NiTiSMA substrate improves the combined function between the ceramic film and NiTiSMA substrate. When the temperature is lower than 20oC, the tanδ of NiTiSMA/FC composites is stabilized at 3.5%, the vibration frequencies (within 0.33-10Hz) have a small effect on damping capacities. Within the temperature of 20-40oC, there is a tanδ peak up to 5.0%.The damping capacities of NiTiSMA/FC composites are better than the pure NiTiSMA materials.

Formation Mechanisms of Sol-Gel Derived Cordierite

2006 ◽  
Vol 45 ◽  
pp. 266-271
Author(s):  
E. Tkalcec ◽  
H. Ivankovic ◽  
J. Macan ◽  
A. Hriberski
Keyword(s):  
Intermediate Phase ◽  
Sol Gel ◽  
Magnesium Nitrate ◽  
Formation Mechanisms ◽  
Sintering Behavior ◽  
Nitrate Hexahydrate ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Magnesium Nitrate Hexahydrate ◽  
Gel Technique

Gels with cordierite stoichiometry, Mg2Al4Si5O18, were prepared by sol-gel technique using three different starting aluminum sources: nano-sized γ-Al2O3, aluminium nitrate nonahydrate and Al-sec-butoxide, as aluminum sources, using tetraetoxysilane (TEOS) and magnesium nitrate hexahydrate in all three gels as sources for silicon and magnesium. The influence of Al-precursors on formation mechanism and sintering behavior of gels was studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and dilatometry. Gels calcined at 700°C were characterized by different specific surface area, pore sizes and different crystallization sequences. For gel with nano-sized γ-Al2O3 α-cordierite was formed at 1220°C through intermediate MgAl2O4 phase. If aluminum was introduced as Al-sec-butoxide μ-cordierite crystallized in two steps (760 and 1070°C) and the transformation μ-cordierite→α-cordierite occurred at 1250°C. When Al(NO3)3·9H2O was introduced as intermediate phase crystallized MgAl2O4 at ~870°C and μ- cordierite at ~950°C. Both phases reacted with amorphous silica forming α-cordierite at ~1210°C. Compacts prepared from gels with aluminum-nitrates and Al-sec-butoxide, respectively, sintered between 700 and 1000°C, whereas the gel derived from γ-Al2O3 sintered in two steps; between 700- 1000°C and 1010 and 1250°C.

scholarly journals Organic–inorganic hybrid coating materials derived from renewable soybean oil and amino silanes

RSC Advances ◽  
2020 ◽  
Vol 10 (27) ◽  
pp. 15881-15887
Author(s):  
Xuyang Luo ◽  
Fei Gao ◽  
Fengbiao Chen ◽  
Qian Cheng ◽  
Jinze Zhao ◽  
...  
Keyword(s):  
Soybean Oil ◽  
Sol Gel ◽  
Hybrid Coating ◽  
Coating Material ◽  
Coating Materials ◽  
Inorganic Hybrid ◽  
One Step ◽  
Gel Technique

A novel coating material was synthesized in one-step comprising two reactions (an amine–acetoacetate reaction and an in situ sol–gel technique).

Super-tough, anti-fatigue, self-healable, anti-fogging, and UV shielding hybrid hydrogel prepared via simultaneous dual in situ sol–gel technique and radical polymerization

2019 ◽  
Vol 7 (45) ◽  
pp. 7162-7175 ◽  
Author(s):  
Juan Du ◽  
Xiaohong She ◽  
Wenli Zhu ◽  
Qiaoling Yang ◽  
Huaju Zhang ◽  
...  
Keyword(s):  
Radical Polymerization ◽  
Mechanical Performance ◽  
Sol Gel ◽  
Hybrid Hydrogel ◽  
Inorganic Hybrid ◽  
Uv Shielding ◽  
Gel Technique

A hydrogel crosslinked by hierarchical inorganic hybrid crosslinks via simultaneous in situ sol–gel technique and radical polymerization exhibits excellent mechanical performance.

scholarly journals Characterization of in-situ zirconia/mullite composites prepared by sol-gel technique

2021 ◽  
pp. 1-7
Author(s):  
Abdu. I. Abdallah ◽  
M. Sayed ◽  
M. Awaad ◽  
Adam H. E. Yousif ◽  
S.M. Naga
Keyword(s):  
Sol Gel ◽  
Gel Technique

Synthesis and Intermolecularly Mediated Assembly of Organic Pigment in Hybrid Coating Films

1998 ◽  
Vol 519 ◽  
Author(s):  
Y. Yan ◽  
Z. Duan ◽  
D.-G. Chen ◽  
S. Ray Chaudhuri
Keyword(s):  
Sol Gel ◽  
Hybrid Coating ◽  
Hypsochromic Shift ◽  
Hybrid Films ◽  
Coating Films ◽  
Organic Pigment ◽  
Inorganic Hybrid ◽  
Matrix Interactions ◽  
Sol Gel Process

AbstractThe insoluble, strongly hydrogen bonded organic pigment of 3,6-bis-(4-chlorphenyl)-l,4- diketopyrrolo [3,4-c] pyrrole was transiently blocked by adding carbamate groups, and consequently incorporated into organic-inorganic hybrid matrices by a sol-gel process. The homo- (pigment-pigment) and hetero-intermolecular (pigment-matrix) interactions were found to control both the assembly and dispersion of pigment molecules in the hybrid coating films. A weaker interaction between matrices and pigment molecules results in aggregation of the carbamate pigment in the methyl-silicate films. A stronger interaction forms a homogenous dispersion and coloration of the phenyl-silicate films. The as-prepared methyl- and phenylsilicate films doped with the organic pigment were distinguished by a morphology change and a blue (hypsochromic) shift in absorption from 550 to 460 nm. Thermal treatment can remove the carbamate groups and in-situ form the organic pigment in the hybrid films.

A NEW ORGANIC/INORGANIC HYBRID WITH HIGH ELECTRORHEOLOGICAL ACTIVITY

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2454-2460 ◽  
Author(s):  
X. P. ZHAO ◽  
X. DUAN
Keyword(s):  
Activation Energy ◽  
Shear Stress ◽  
Necessary Conditions ◽  
Sol Gel ◽  
Root Temperature ◽  
Sedimentation Stability ◽  
Inorganic Hybrid ◽  
Active Particles ◽  
Static Shear

In-situ sol-gel method to prepare colloidal hybrids of surfactant modified polysucchride and titanium oxide has been presented, and experiments indicated these highly ER active particles exhibited a remarkable ER effect. The static shear stress can be up to 37 k Pa (shear rate 5 S -1) under DC field of 4 kV/mm at root temperature, well above that of simple blends of starch and TiO 2. In the meanwhile, temperature dependence and sedimentation stability were also greatly improved. Based on recent experimental facts, we find that dielectric properties and surface (interface) activity are two necessary conditions fulfilling the requirement of high ER activity. Adequate grinding of particles with oil can effectively enhance the shear stress, which may be owed to the decline of the activation energy needed for restructuring. It has provided us a new horizon for preparation of excellent ER materials and further studies should be continued to make.

Preparation and Characterization of Zn-Containing Hydroxyapatite/TiO2 Composite Coatings on Ti Alloys

2011 ◽  
Vol 685 ◽  
pp. 367-370 ◽  
Author(s):  
Min Qi ◽  
Da Yi Yang ◽  
Jing Ying Zhang ◽  
Hong Jun Ai
Keyword(s):  
Adhesion Strength ◽  
Composite Coatings ◽  
Energy Dispersive Spectrometer ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Zn Content ◽  
Micro Arc Oxidation ◽  
Gel Technique ◽  
Bacteria Resistance

In order to improve the osteoblast growth and bacteria resistance, Zn-containing hydroxyapatite (Zn-HA) and titanium oxide (TiO2) composite coatings were prepared to improve binding between coating and Ti substrate. TiO2 film was prepared on the surface of Ti by micro-arc oxidation (MAO) and Zn-HA coating was deposited on TiO2 using sol–gel technique. Phase structure, composition and microstructure of the surface coatings were analyzed by X-ray diffraction (XRD) and Energy Dispersive Spectrometer (EDS), respectively. The adhesion strength between the coatings with different Zn content was measured by tensile testing. The results showed that there was no significant influence of Zn content on adhesion strength between coating and Ti substrate.

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