Papers by Keyword: FT-IR

Abstract: The main point of this paper is to assess the level of corrosion damage of the composite textile fiberglass reinforcement in environments that simulate the concrete pore solution by the techniques of FT-IR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy) as well as EDS (scanning electron microscopy). Effect of corrosion on the tensile strength segmented textile glass fiber was tested and also it was investigated specific type of protective organic coating on glass fiber. The results express the evidence of local corrosion damage on the examined samples just at pH 13.5, and on the contrary high stability in the environment simulating carbonated concrete and concrete contaminated by chloride anions. The thesis also points on the unevenness of the excluded protective organic coating with localized porosity which relates to the above mentioned corrosion damage.

Abstract: This paper explores the effect of prior enzymatic treatment on non-formaldehyde crosslinked cotton fiber and crystalline structure of cotton fibers after enzyme, crosslinking and a combination of enzyme and crosslinking treatments were examined by X-ray diffractometer. Results showed that during crosslinking treatment crystallinity index (%) values were increased with reduced crystallinity size and crosslinked of enzyme treated cotton did not change the crystalline nature of cotton (i.e. it was Cellulose I). In addition, by analysing FT-IR and SEM data it is confirmed that uniform presence of crosslinking agents was visible on cotton fibres.

Abstract: Up to date, no extravagant attempts have been made to use the vegetable oil-based polyols as rejuvenator agents for aged asphalts. In this context, the nature and composition of these biodegradable products need to be identified and physicochemical properties of different nature of compounds need to be measured. Three different vegetable oil-based polyols designed as castor oil polyol, soybean flexible polyol, and soybean rigid polyol were characterized by FT-IR, TLC-FID, ¹H-NMR, and ¹³C-NMR and by the determination of some usual characteristics such as acid value, hydroxyl value, iodine value, and viscosity. It is speculated that the soybean flexible polyol may serve as a potential rejuvenator for aged asphalts.

Abstract: Bioactive glasses have widely used in biomedical applications such as bone filler due to their excellent biocompatibility, bioactivity and osteoconduction characteristics. In this work, a silicate-rich glass was synthesized by the sol-gel method with 60% SiO₂ – 30%CaO – 10% MgO composition where fumed silica acts as the silica precursor. This new method was hypothesized to reduce the gel formation time, due to the high surface area of the fumed silica. In addition, this would presumably increase the nanoporosity of the glass. For comparison purposes, we used a glass of the same composition, but with the conventional silica precursor, tetraethyl orthosilicate (TEOS), through the sol gel method. Both were heat treated at 450°C. FT-IR analysis before and after heat treatment at 450°C showed the presence of nitrate groups, especially in the TEOS samples. This is consistent with the more hygroscopic aspect of those samples. The fumed silica samples had significantly less pronounced peaks corresponding to the nitrate groups, consistent with the more porous structure and the less hygroscopic aspect. The fumed silica samples indeed had a lower gelling time and showed similar results obtained by XRD and FT-IR analyses, showing that the use of fumed silica is viable and advantageous in the glass synthesis by the sol-gel process

Abstract: In this study, we investigated the physical and chemical state changes of silver in silver-containing hydroxyapatite (AgHA) composites sintered at various heat treatment temperatures. AgHA composites were synthesized by a solid phase reaction at various temperatures using composite powder prepared by ball-milling commercial highly crystalline hydroxyapatite powder and commercial silver oxide powder. Structural characterization of AgHA was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray absorption near edge structure (XANES). The XRD measurement showed that peaks of metallic silver or other silver compounds disappeared at 800°C and reappeared at 1000°C. The a-axis of HA obtained by Rietveld analysis expanded drastically at 800°C. Furthermore, the SEM images showed that silver particles disappeared at 800°C and reappeared at 1000°C, as indicated by the XRD patterns. The XANES spectrum of Ag-L₃ edge of AgHA sintered at 800°C was different compared to those of other references. These results suggested that calcium ions were substituted by silver ions in AgHA sintered at 800°C, according to the a-axis expansion of HA lattice caused by the substitution of hydroxyl ions by carbonate ions through the heat treatment, based on the FT-IR measurement. In addition, antibacterial tests showed that AgHA containing various chemical states of silver had good antibacterial activities in proportion to released amounts of silver.

Abstract: Hydroxyapatite Ca₁₀(PO₄)₆(OH)₂: (HAp) with stoichiometric composition and Ca/P (ratio) = 1.67 has attracted much attention in the context of bone transplant due to its similarity with the mineral constituent of mammals bone and teeth. It is frequently used as a filler to replace amputated bone or as a coating to promote bone ingrowth into prosthetic implants. Biomimetics or biomimicry is the imitation of the models, systems, and elements of nature for the purpose of solving complex human problems. Living organisms have evolved well-adapted structures and materials over geological time through natural selection. Biomimetics has given rise to new technologies inspired by biological solutions at macro and nanoscales. Nanostructure modification of dental implants has long been sought as a means to improve osseointegration through enhanced biomimicry of host structures. Several methods have been proposed and demonstrated for creating nanotopographic features.In the present investigation hydroxyapatite and metals (scandium, magnesium and neodymium) doped hydroxyapatite were successfully synthesized in laboratory by chemical precipitation using hydrothermal route and also by taking ethylene diamine tetra-acetic acid as a complexing reagent. The crystal, grain, and bonding structures of resulting HAp were characterized structurally using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques and spectroscopically using Fourier transform infrared (FT-IR) techniques. From SEM analysis it was found that the irregular structure of HAp changes to nanorods with EDTA HAp which further gets converted to dandelium structure with scandium doping, plate structure with magnesium doping and whiskers structure on doping with neodymium.

Abstract: This paper presents preliminary results of modified Montmorillonite samples and the surface treatment with hydrochloric acid were investigated. The modification of this Montmorillonite surface, negatively charged and exchanged by organic cations such as alkylammoniums (Trimethylexadecyl C16 and Trimethyloctadecyl C18), yields a modified Montmorillonite (MMt). The resulting organo-mineral material acquires an organophilic character which could be used in several applications. The organically modified MMts were prepared by an ion exchange process in which sodium ions were replaced by alkylammonium ions. This material, used in the present work, is an Algerain montmorillonite obtained from MAGHNIA (West Algeria). Octadecyltrimethylammonium and hexadecyltrimethylammonium chlorides, utilized here as surfactants activators to organophilize the Montmorillonite. The microstructure of this modified Montmorillonite was characterized by XRD-diffraction with which the effects of the intercalation associated to the conformation of the long hydrocarbon chain were investigated. The results obtained showed that the amounts of hydrochloric acid added to these modified materials affect considerably the conformation of the intercalated surfactants. Their physical characteristics were determined by infrared spectrophotometer (FT-IR) and their chemical modification revealed that their thermal properties have been advantageously improved.

Abstract: We fabricated Si:SiO₂ films and assessed its characterization of photoluminescence and surface chemistry. When Si tablets on a SiO₂ target were sputtered in a chamber of a radio frequency sputtering device, Si:SiO₂ films were deposited on a substrate. When the films were excited by a He-Cd laser, photoluminescence having wide and continuous peaks was emitted in shorter region than 600 nm. After annealing, intensity of photoluminescence changed, which depends on annealing temperature and time. By the Fourier Transform InfraRed Spectroscopy, bonds of atoms around Si were investigated.

Abstract: Pyrolysis process in a fixed bed reactor was performed to derive pyrolytic oil from groundnut shell. Experiments were conducted with different operating parameters to establish optimum conditions with respect to maximum pyrolytic oil yield. Pyrolysis process was carried out without catalyst (thermal pyrolysis) and with catalyst (catalytic pyrolysis). The Kaolin is used as a catalyst for this study. The maximum pyrolytic oil yield (39%wt) was obtained at 450°C temperature for 1.18- 2.36 mm of particle size and heating rate of 60^°C/min. The properties of pyrolytic oil obtained by thermal and catalytic pyrolysis were characterized through Fourier Transform Infrared Spectroscopy (FT-IR) and Gas Chromatography-Mass Spectrometry (GC-MS) techniques to identify the functional groups and chemical components present in the pyrolytic oil. The study found that catalytic pyrolysis produce more pyrolytic oil yield and improve the pH value, viscosity and calorific value of the pyrolytic oil as compared to thermal pyrolysis.

Abstract: Both qualitative and quantitative effect of TiO₂ suspension presence in cigarette filter have been analyzed in order to reduce harmful substances in cigarette smoke, optimizing the capability of TiO₂ suspension as nano filter in cigarette filters and reviewing the analysis in order to obtain results with the best variation. Samples in the form of filter paper that has passed of the smoke with some variation treatment as it become ready to be tested and analyzed. Parameter such as concentration and volume variation of TiO₂ suspension, and also the inputting method of TiO₂ suspension into cigarette filter. Samples were characterized using FT-IR spectrophotometer and samples data absorbance obtained in each catchment area. The results showed that by reducing absorbance value percentage of each catchment area, with inputting method of TiO₂ suspension through the cigarette filter tip and base, it appears that the most stable and lowest reduction present in C3 and H3, which is sample with 1.85 mol/liter concentration and 0.3 ml suspension volume. Both sample reduced particulate matters significantly after confirmed with X-Ray Fluorescence and SEM-EDS results, and was compared to sample filter without TiO_2. Inputting method of TiO₂ suspension through a base of cigarette butt is better and safer than through end of cigarette filter.