scholarly journals Chemical modification and characterization of boehmite particles

2008 ◽  
Vol 2 (1) ◽  
pp. 27-32
Author(s):  
Witold Brostow ◽  
◽  
Tea Datashvili ◽  
Keyword(s):  
Fourier Transform ◽  
Water Adsorption ◽  
Surface Characteristics ◽  
Surface Hydrophobicity ◽  
Hydroxyl Groups ◽  
Commercial Alumina ◽  
Inorganic Hybrid ◽  
Oh Groups ◽  
Powder Surface

Polymerizable organic silane molecules 3-(trimethoxysilyl)propylmethacrylate (3MPS) and vinyltri(2-methoxyethoxy)silane (VTMES) have been introduced onto surfaces of high purity Boehmite (a commercial alumina) via hydroxyl groups on the oxides in order to obtain organic-inorganic hybrid “macromonomers”. Changes of surface characteristics have been determined using thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR). The influence of the type of silane used and modification conditions have been determined. Preheating was applied to some Boehmite samples; it leads to lower concentrations of –OH groups on the powder surface and the adsorption yields lower than in samples without preheating. Modification leads to surface hydrophobicity and thus reduces significantly water adsorption; in TGA we see desorption of water below 423 K only in un-modified Boehmite.

scholarly journals Water adsorption and hygroscopic growth of six anemophilous pollen species: the effect of temperature

2019 ◽  
Vol 19 (4) ◽  
pp. 2247-2258 ◽  
Author(s):  
Mingjin Tang ◽  
Wenjun Gu ◽  
Qingxin Ma ◽  
Yong Jie Li ◽  
Cheng Zhong ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Populus Tremuloides ◽  
Water Adsorption ◽  
Effect Of Temperature ◽  
Relative Mass ◽  
Hygroscopic Growth ◽  
Oh Groups ◽  
Hygroscopic Properties ◽  
Pollen Species ◽  
Mass Increase

Abstract. Hygroscopicity largely affects environmental and climatic impacts of pollen grains, one important type of primary biological aerosol particles in the troposphere. However, our knowledge of pollen hygroscopicity is rather limited, and the effect of temperature in particular has rarely been explored before. In this work three different techniques, including a vapor sorption analyzer, diffusion reflectance infrared Fourier transform spectroscopy (DRIFTS) and transmission Fourier transform infrared spectroscopy (transmission FTIR) were employed to characterize six anemophilous pollen species and to investigate their hygroscopic properties as a function of relative humidity (RH, up to 95 %) and temperature (5 or 15, 25 and 37 ∘C). Substantial mass increase due to water uptake was observed for all the six pollen species, and at 25 ∘C the relative mass increase at 90 % RH, when compared to that at <1 % RH, ranged from ∼30 % to ∼50 %, varying with pollen species. It was found that the modified κ-Köhler equation can well approximate mass hygroscopic growth of all the six pollen species, and the single hygroscopicity parameter (κ) was determined to be in the range of 0.034±0.001 to 0.061±0.007 at 25 ∘C. In situ DRIFTS measurements suggested that water adsorption by pollen species was mainly contributed to by OH groups of organic compounds they contained, and good correlations were indeed found between hygroscopicity of pollen species and the number of OH groups, as determined using transmission FTIR. An increase in temperature would in general lead to a decrease in hygroscopicity, except for pecan pollen. For example, κ values decreased from 0.073±0.006 at 5 ∘C to 0.061±0.007 at 25 ∘C and to 0.057±0.004 at 37 ∘C for Populus tremuloides pollen, and decreased from 0.060±0.001 at 15 ∘C to 0.054±0.001 at 25 ∘C and 0.050±0.002 at 37 ∘C for paper mulberry pollen.

Synthesis and Characterization of UV-Thermal Dual Hybrid Curable Organosilicon Modified Epoxy Monoacrylates

2012 ◽  
Vol 152-154 ◽  
pp. 657-660
Author(s):  
Hong Bo Liu ◽  
Feng Lin ◽  
Wu Ying Zhang
Keyword(s):  
Fourier Transform ◽  
Synthesis Process ◽  
Synthesis And Characterization ◽  
Titration Method ◽  
Uv Curable ◽  
Oh Groups ◽  
Acrylic Ester ◽  
Modified Epoxy ◽  
Epoxy Groups

New UV-thermal dual hybrid curable organosilicon-modified epoxy monoacrylates (OMEMA) were synthesized in this study. The changes of NCO groups during the synthesis process of OMEMA were measured by chemical titration method, and its Fourier Transform Infrared (FTIR) spectra were investigated. The results indicate that organosilicon chain segments can be grafted onto the epoxy monacrylates (EMA) by the reaction of NCO and OH groups. The FTIR of OMEMA show that it contains both double bond of acrylic ester (UV curable) and epoxy groups (thermal curable).

scholarly journals Water Adsorption Properties of Free and Dehydrated β-Cyclodextrin Studied by near Infrared Spectroscopy and Gravimetry

2016 ◽  
Vol 689 ◽  
pp. 143-147 ◽  
Author(s):  
Alfred A. Christy
Keyword(s):  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Water Adsorption ◽  
Near Infrared ◽  
Adsorption Properties ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Near Infrared Spectra ◽  
Adsorption Of Water

β-cyclodextrin, like other carbohydrates has a tendency to adsorb water molecules and the properties are attributed to the hydroxyl groups in the molecules. β-cyclodextrin, the cyclic oligomer of glucose has a hydrophobic interior and hydrophilic exterior. The cyclic structure favours the formation of hydrogen bonds between the OH groups on the adjacent glucose units and affects the formation of hydrogen bonds with water molecules. The hydoxyl groups engaged in hydrogen bondings can be eliminated at high temperatures and the adsorption properties of the dehydrated β-cyclodextrin will depend on the new functional groups formed. The aim of the report is to discuss the issue of the water adsorption properties of free and dehydrated β-cyclodextrin. Dry β-cyclodextrin and dehydrated β-cyclodextrin at temperatures 250, 300 and 350 °C were allowed to adsorb water from a humidity controlled air environmennt and the evolving near infrared spectra were measured using a near infrared spectrometer equipped with a transflectance accessory. The near infrared spectra in the region 10,000-4000 cm-1 and their second and fourth derivative profiles were used in studying the variation in the adsorption characteristics of dehydrated β-cyclodextrin. The results of the analyses show that the adsorption of water by β-cyclodextrin decreses at 300 °C compared to 200 and 250 °C. Dehydration forms more of the ethereal type-O-bonds in the molecule and explains the decrease in the water molecular adsorption at higher dehydration temperatures.

Fourier transform infrared analysis of hydroxyl content of hydrothermally processed heteroepitaxial barium titanate films

2005 ◽  
Vol 20 (12) ◽  
pp. 3312-3319 ◽  
Author(s):  
Sandeep K. Patil ◽  
Nipun Shah ◽  
Frank D. Blum ◽  
Mohamed N. Rahaman
Keyword(s):  
Fourier Transform ◽  
Barium Titanate ◽  
Exchange Reaction ◽  
Photoelectron Spectroscopy ◽  
Fourier Transform Infrared ◽  
Infrared Analysis ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Kinetics Of ◽  
Total Reaction Time

The concentration of hydroxyl (–OH) groups in epitaxial barium titanate (BaTiO3) films (thickness ∼ 200 nm), deposited on single-crystal strontium titanate (SrTiO3) at 150 °C by a hydrothermal technique, was investigated using x-ray photoelectron spectroscopy and Fourier transform infrared (FTIR) spectroscopy. After hydrothermal treatment, a broad FTIR resonance for the hydroxyl groups indicated a significant concentration of surface –OH groups in the films. The as-deposited films were subsequently treated hydrothermally with D2O, and the kinetics of the exchange reaction between –OH incorporated into the film and –OD from the D2O were studied using FTIR. For reactions carried out intermittently, the kinetics of the exchange reaction between –OH by –OD depended not only on the total reaction time, but also on the duration of each treatment. The broad FTIR hydroxyl resonance in the as-deposited hydrothermal film was significantly reduced only after heating for 1 h at 600–800 °C.

scholarly journals Characterization of Modified and Polymer Coated Alumina Surfaces by Infrared Spectroscopy

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Ashraf Yehia El-Naggar
Keyword(s):  
Infrared Spectroscopy ◽  
Alkali Metal ◽  
Ftir Spectroscopy ◽  
Surface Properties ◽  
Adsorption Properties ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Structure Changes ◽  
The Individual

The prepared, modified, and coated alumina surfaces were characterized by infrared spectroscopy (FTIR) to investigate the surface properties of the individual and double modified samples. FTIR helps in reporting the changes occurred in hydroxyl groups as well as the structure changes as a result of thermal treating, hydrothermal treating, silylation treating, alkali metal treating, coating, and bonding with polymer. FTIR spectroscopy represents the strength and abundance of surface acidic OH which determine the adsorption properties of polar and nonpolar sorbents. Generally, all treated samples exhibit decrease of OH groups compared with those of parent ones producing alumina surfaces of different adsorptive powers.

Characterization of Boron Modified Phenolic Resin and its Curing Behavior

2011 ◽  
Vol 233-235 ◽  
pp. 137-141 ◽  
Author(s):  
Biao Li ◽  
Yun Wu Zheng ◽  
Zhi Feng Zheng ◽  
Xiong Yue Zhao
Keyword(s):  
Fourier Transform ◽  
Heat Resistance ◽  
Boric Acid ◽  
Infrared Spectra ◽  
Differential Scanning Calorimeter ◽  
Phenolic Resin ◽  
Curing Temperature ◽  
Hydroxyl Groups ◽  
Curing Behavior

Boron modified phenolic (BPF) resins with different boron amounts were synthesized with a special synthesis technology. The structure of BPF resin was analyzed by Fourier transform infrared spectra (FTIR) and its curing behavior was analyzed by differential scanning calorimeter (DSC). The results showed that boric acid reacted with the hydroxyl groups in phenolic resin to form a new cross-linked bond such as B-O. At the same time, the heat resistance of BPF resin was improved about 18% with addition of boric acid of 0.8wt%. The obtained BPF had a high curing temperature of 254.6when the boric acid amount was 0.8wt%.

XPS Investigation on Nano-TiO2 Modified by Titanate Coupling Agent

2008 ◽  
Vol 368-372 ◽  
pp. 1477-1479 ◽  
Author(s):  
Dong Mei Zhang ◽  
Hai Li Yang ◽  
Shou Wu Yu ◽  
Xiao Ming Sang
Keyword(s):  
Carbon Content ◽  
Coupling Agent ◽  
Photoelectron Spectroscopy ◽  
Coupling Reaction ◽  
Surface Characteristics ◽  
Hydroxyl Groups ◽  
Nano Tio2 ◽  
Oh Groups ◽  
X Ray ◽  
Bare Tio2

Nano-TiO2 was modified with a titanate coupling agent, LICA38 [neopentyl (dially) oxy, tri (-dioctyl) pyrophosphate titanate]. X-ray photoelectron spectroscopy (XPS) was used to evaluate the surface characteristics of the bare and the modified nano-TiO2. It was demonstrated that the carbon content of the bare TiO2 is 37.9 atm. %, and that of the modified TiO2 is 47.2 atm. %. Moreover, the density of the -C-H (-C-C) and -C-O groups increases due to modification, and the atomic percentage of C=O and -OH groups reduces. These results indicate that the -C-H (-C-C) and -C-O groups from LICA38 have been introduced to the surface of nano-TiO2 by coupling reaction with the hydroxyl groups.

The Determination of Hydroxyl Groups in Coal by Fourier Transform Infrared and 13C NMR Spectroscopy

1983 ◽  
Vol 37 (6) ◽  
pp. 497-502 ◽  
Author(s):  
R. W. Snyder ◽  
P. C. Painter ◽  
J. R. Havens ◽  
J. L. Koenig
Keyword(s):  
Fourier Transform ◽  
Nmr Spectroscopy ◽  
Fourier Transform Infrared ◽  
13C Nmr Spectroscopy ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
The Individual ◽  
Oh Content ◽  
C Nmr

Fourier transform infrared spectroscopy and solid state 13C NMR spectroscopy have been used to measure the hydroxyl groups in coal. The methodology depends upon measuring the intensities of bands and resonances assigned to the products of acetylation reactions. In the infrared three separate bands, assigned to acetylated phenolic OH, alkyl OH, and NH groups, can be identified. In NMR, we used the methoxy carbon to determine the total OH. Spectroscopic measurements demonstrate that not only does the total OH content of coals but also the individual types of OH groups vary systematically as a function of rank. The proportion of phenolic to alkyl OH is approximately constant for the coals used in this study.

Infrared Spectroscopy Characterization of Marine Shells

2001 ◽  
Vol 711 ◽  
Author(s):  
Octavio Gomez-Martinez ◽  
Daniel H. Aguilar ◽  
Patricia Quintana ◽  
Juan J. Alvarado-Gil ◽  
Dalila Aldana ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Crassostrea Virginica ◽  
Thermal Treatments ◽  
Vibration Modes ◽  
Lattice Vibrations ◽  
Vibration Frequencies ◽  
Mussel Shells ◽  
Carbonate Lattice

ABSTRACTFourier Transform infrared spectroscopy has been employed to study the shells of two kind of mollusks, American oysters (Crassostrea virginica) and mussels (Ischadium recurvum). It is shown that it is possible to distinguish the different calcium carbonate lattice vibrations in each case, mussel shells present aragonite vibration frequencies, and the oyster shells present those corresponding to calcite. The superposition, shift and broadening of the infrared bands are discussed. Changes in the vibration modes due to successive thermal treatments are also reported.

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