Synthesis, Rheological Behavior and Mechanical Characterization of Structural Fast-Setting Geopolymers

2005 ◽  
Vol 498-499 ◽  
pp. 488-493
Author(s):  
Antonio Eduardo Martinelli ◽  
D.M.A. Melo ◽  
E.P. Marinho ◽  
T.W.J. Batista ◽  
R.G.S. Araújo ◽  
...  
Keyword(s):  
Potassium Hydroxide ◽  
Room Temperature ◽  
Mechanical Characterization ◽  
Potassium Hydroxide Solution ◽  
Inorganic Materials ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Polymeric Precursor ◽  
Rheological Characterization

Geopolymers are inorganic materials with ceramic characteristics that can be synthesized at room temperature from the setting of slurries. Their structure consists of aluminosilicate units that polymerize in alkaline environment. The setting rate and mechanical behavior of geopolymers strongly depends on the SiO2:Al2O3 molar ratio, polymeric precursor and polymerization cation. The present work reports the synthesis and characterization of 3.5:1 (SiO2:Al2O3) structural geopolymers prepared using either metakaolin (GPMK) or kaolin (GPK) as geopolymeric precursor in potassium hydroxide solution. GPMK depicted quick setting whereas GPK set only after 4 hours. The rheological characterization of the slurries revealed that plastic viscosity and yield point of GPK were 0.40 Pa.s and 14.2 Pa, respectively, whereas GPMK set instantly. The compressive strength of both geopolymers were measured after 24 hours and resulted in similar results, i.e., 4.6 MPa for GPMK and 4.4 MPa for GPK. The strength of both geopolymers was compatible to values typical of structural materials.

scholarly journals Synthesis and characterization of new Oxazine , Thiazine and Pyrazol derived from chalcones

2014 ◽  
Vol 11 (2) ◽  
pp. 477-485 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Nmr Spectroscopy ◽  
Hydrazine Hydrate ◽  
Elemental Analysis ◽  
Potassium Hydroxide ◽  
1H Nmr Spectroscopy ◽  
Room Temperature ◽  
Potassium Hydroxide Solution ◽  
Synthesis And Characterization ◽  
Heterocyclic Derivatives

In this study, chalcones were synthesis by condensing 2-acetylpyridine with aromatic aldehyde derivatives in dilute ethanolic potassium hydroxide solution at room temperature according to Claisen-Schmidt condensation. After that, new heterocyclic derivatives such as Oxazine, Thiazine and Pyrazol were synthesis by reaction between chalcones with urea, thiourea and hydrazine hydrate respectively scheme 1. All these compounds wrer characterization by FTIR, 1H-NMR spectroscopy and elemental analysis.

scholarly journals Synthesis and characterization of a new ZIF-67@MgAl2O4 nanocomposite and its adsorption behaviour

RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13245-13255
Author(s):  
Mehdi Davoodi ◽  
Fatemeh Davar ◽  
Mohammad R. Rezayat ◽  
Mohammad T. Jafari ◽  
Mehdi Bazarganipour ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnesium Aluminate ◽  
Synthesis And Characterization ◽  
Magnesium Aluminate Spinel ◽  
Adsorption Behaviour ◽  
Zeolitic Imidazolate Framework ◽  
Simple Method

New nanocomposite of zeolitic imidazolate framework-67@magnesium aluminate spinel (ZIF-67@MgAl2O4) has been fabricated by a simple method at room temperature with different weight ratios.

scholarly journals Synthesis and Characterization of Polyphosphazenes Modified with Hydroxyethyl Methacrylate and Lactic Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Evelyn Carolina Martínez Ceballos ◽  
Ricardo Vera Graziano ◽  
Gonzalo Martínez Barrera ◽  
Oscar Olea Mejía
Keyword(s):  
Lactic Acid ◽  
Ring Opening ◽  
Room Temperature ◽  
Block Structure ◽  
Ring Opening Polymerization ◽  
Synthesis And Characterization ◽  
Poly Lactic Acid ◽  
Hydroxyethyl Methacrylate ◽  
H Nmr

Poly(dichlorophosphazene) was prepared by melt ring-opening polymerization of the hexachlorocyclotriphosphazene. Poly[bis(2-hydroxyethyl-methacrylate)-phosphazene] and poly[(2-hydroxyethyl-methacrylate)-graft-poly(lactic-acid)-phosphazene] were obtained by nucleophilic condensation reactions at different concentrations of the substituents. The properties of the synthesized copolymers were assessed by FTIR,1H-NMR and31P-NMR, thermal analysis (DSC-TGA), and electron microscopy (SEM). The copolymers have a block structure and show twoTg's below room temperature. They are stable up to a temperature of 100°C. The type of the substituents attached to the PZ backbone determines the morphology of the polymers.

Synthesis and Characterization of Poly(Aryl Ether Quinoxaline)s with Controlled Molecular Weight

2011 ◽  
Vol 391-392 ◽  
pp. 826-829
Author(s):  
Song Ya Zhang ◽  
Zhong Xiao Li ◽  
Jia Ling Pu
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Strong Acid ◽  
Decomposition Temperature ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Aryl Ether ◽  
Good Solubility ◽  
Step Procedure

Novel poly(aryl ether quinoxaline)s (PEQs) were prepared via a two-step procedure. First, poly (ether benzil) (PEB) was synthesized by the polycondensation of 4,4’-difluorobenzil and 4,4’-isopropylidenediphenol.Then, PEB was reacted with 1,2-diaminobenzene and 4,4'-oxydibenzene-1,2-diamine to give the PEQs. The molecular weight of the PEQs could be adjusted easily by varying the molar ratio of 1,2-diaminobenzene to 4,4'-oxydibenzene-1,2-diamine. The PEQs exhibited good solubility in common organic solvents such as NMP, DMAc, DMF, cyclohexanone and chloroform. In addition, the PEQs also had high glass transition (Tg) temperatures and good thermal properties, with an initial thermal decomposition temperature above 475 oC and glass transition temperatures above 210 oC. They also exhibited excellent resistance to strong acid and alkali.

Synthesis and characterization of Au, Pt supported on graphene aerogel catalysts for CO oxidation at low temperature

2021 ◽  
Vol 11 (1) ◽  
pp. 118-122
Author(s):  
Chuyen Phan Thi ◽  
Hang Tran Thi Thanh ◽  
Phong Pham Nam ◽  
Ha Vu Thi Thu
Keyword(s):  
Low Temperature ◽  
Ambient Temperature ◽  
Co Oxidation ◽  
Pt Nanoparticles ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Graphene Aerogel ◽  
Highly Dispersed ◽  
Average Size

Au, Pt supported on graphene aerogel catalysts (PtAu/rGOA) with molar ratio of Pt and Au of 1:1, and total metal concentration of 5 % were successfully synthesized by hydrothermal method.  The obtained catalysts were characterized by Raman, XRD, XPS, HR-TEM, BET. It revealed that Au and Pt nanoparticles with average size of 3 – 5 nm were highly dispersed on aerogel graphene. The activity of these catalysts was tested  in CO oxidation. The results showed that the conversion of CO at ambient temperature was 100% during 25 minutes. Accordingly, PtAu/rGOA could be considered as a potential catalysts for CO oxidation at low temperature.

scholarly journals H/D Exchange Under Mild Conditions in Arenes and Unactivated Alkanes with C6D6 and D2O Using Rigid, Electron-rich Iridium PCP Pincer Complexes

2020 ◽  
Author(s):  
Joel D. Smith ◽  
George Durrant ◽  
Daniel Ess ◽  
Warren Piers
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Room Temperature ◽  
Pincer Complexes ◽  
Synthesis And Characterization ◽  
Hydrogen Isotope Exchange ◽  
Mild Conditions ◽  
Highly Active ◽  
Pcp Pincer

<div>The synthesis and characterization of an iridium polyhydride complex (Ir-H4)</div><div>supported by an electron-rich PCP framework is described. This complex readily loses molecular</div><div>hydrogen allowing for rapid room temperature hydrogen isotope exchange (HIE) at the hydridic</div><div>positions and the α-C-H site of the ligand with deuterated solvents such as benzene-d6, toluene-d8</div><div>and THF-d8. The removal of 1-2 equivalents of molecular H2 forms unsaturated iridium carbene</div><div>trihydride (Ir-H3) or monohydride (Ir-H) compounds that are able to create further unsaturation</div><div>by reversibly transferring a hydride to the ligand carbene carbon. These species are highly active</div><div>hydrogen isotope exchange (HIE) catalysts using C6D6 or D2O as deuterium sources for the</div><div>deuteration of a variety of substrates. By modifying conditions to influence the Ir-Hn speciation,</div><div>deuteration levels can range from near exhaustive to selective only for sterically accessible sites.</div><div>Preparative level deuterations of select substrates were performed allowing for procurement of</div><div>>95% deuterated compounds in excellent isolated yields; the catalyst can be regenerated by</div><div>treatment of residues with H2 and is still active for further reactions.</div>

scholarly journals Synthesis and Characterization of Natural Fibers Reinforced Fiber Epoxy Composites

2015 ◽  
Vol 51 ◽  
pp. 47-53
Author(s):  
U. Mahaboob Basha ◽  
D. Mohana Krishnudu ◽  
P. Hussain ◽  
K. Manohar Reddy ◽  
N. Karthikeyan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Natural Fibers ◽  
Epoxy Composites ◽  
Synthesis And Characterization ◽  
Mechanical And Thermal Properties ◽  
Epoxy System ◽  
Pennisetum Typhoides ◽  
The Matrix ◽  
Reinforced Fiber

In the current work epoxy resin is chosen as matrix, treated Sacharum offinarum ( SugarCane) fiber, Pennisetum typhoides (Jowar)/ Fillet miller (Ragi) filler are chosen as reinforcement. Room temperature cured Epoxy System filled with Sacharum offinarum fiber and Pennisetum typhoides (Jowar)/ Fillet miller (Ragi) filler are synthesised by mechanical shear mixer, then kept in a Ultra sonic Sonicator for better dispersion of Pennisetum typhoides (Jowar)/ Fillet miller (Ragi) filler in the matrix. Different weights of modified Pennisetum typhoides (Jowar)/ Fillet miller (Ragi) filler (1,2,3,4,5 gm wt) has been incorporated into the Epoxy matrix in order to study the variation of Mechanical and Thermal properties.

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