Any unusual peaks may indicate the presence of contaminants or oxidation.
The background spectrum should be collected on a pure KBr pellet.
One should collect and average at least 32 scans in transmission mode with an FTIR bench. If done correctly, the KBr pellet should be transparent, with semiopaque regions where the UHMWPE powder is sitting. One should place enough powder to cover the bottom of the mold, then press. The two powders should be ground together with a mortar and pestle and then placed in a KBr pellet anvil. The UHMWPE powder is blended in a 1:20 ratio with KBr powder that has been carefully dried in an oven to remove all absorbed water. An FTIR with a microscope attachment, which is useful for examining the chemical structure as a function of position in a sample, is shown in Figure 24.11. FTIR can be performed on either the UHMWPE powder using the potassium bromide (KBr) pellet technique or on the consolidated UHMWPE. Although FTIR can be used for the characterization of dried materials after soaking or after implantation and removal, in situ measurements are hindered by the strong adsorption of water in the infrared region.įTIR is performed to measure the chemical structure of the UHMWPE. The spectra show that the HCA layer thickness was thicker for the powders and foams with respect to the monolith. Figure 5 shows FTIR spectra of three forms of the sol–gel derived bioactive glasses of the 58S composition (60 mol.% SiO 2, 36 mol.% CaO, 4 mol.% P 2O 5) that were soaked in SBF for 2 h. The relative intensity of the bands can be used to monitor growth of the layer as a function of time. Stretching and bending vibration bands for the amorphous silica network are also present in the spectra. The crystalline HCA layer is characterized by the P–O bending vibration bands at 560 and 604 cm –1 (infrared wave number). FTIR spectra of the glass surface area usually taken after a glass sample has been reacted in simulated body fluid (SBF) and dried. In PDMS-based composites, both silica and titania have been well studied regarding this IR absorption.įTIR spectra have been used to determine the rate of formation of the HCA layer on bioactive glasses and the technique is used as a quality assurance (QA) test for bioactivity. More conveniently, when this vibration combines with the bending mode of water molecules, it generates bands from 5050 to 5350 cm −1 range. For example, the physically-absorbed water can be characterized through peaks between 38 cm −1 (i.e., OH stretching vibrations). This gives FTIR an advantage, i.e., it results in a higher signal-to-noise ratio for a specific scanning time.įTIR can be used for microscopy and imaging of rubber and particle interfacial modifications. In FTIR, light of many frequencies can be measured simultaneously and this process can be repeated many times. Repeating corresponding test parameters can control the number of measurements for each different wavelength. A straightforward way for this absorption measurement is to shine a monochromatic light beam at a sample and measure how much of it is absorbed. For a typical FTIR, the resolution is 4 cm −1. FTIR can be used to collects high spectral resolution data over a wide range, usually between 5000 and 400 cm −1 for mid-IR region wavelength, and between 10,0 cm −1 for near-IR region wavelength. Song, in Progress in Rubber Nanocomposites, 2017 4.2.4.2 Fourier transform infrared spectroscopy (FTIR)įourier transform infrared spectroscopy (FTIR) is the technique used to obtain an infrared spectrum of absorption or emission of a solid, liquid and gas. Many other examples are reported in which FT-IR has been used as primary and important tool for the characterization of nanoparticles. During the biosynthesis of gold nanoparticles using Magnolia kobus and Diospyros kaki leaves extracts, the IR spectra reveals the presence of hydroxyl groups of alcohols and the phenolic groups in the structure ( Song et al., 2009). Plant extracts were efficient at binding with iron-oxide nanoparticles through carbonyl groups of proteins, which helped to stabilize the hematite nanoparticles ( Asou et al., 2018). The FT-IR spectrum of green synthesized iron-oxide revealed the chemical linkage of the functional groups. The most popular application of FT-IR is to investigate the functional group present in the given compound ( Kong and Yu, 2007). FT-IR spectroscopy helps researchers to get information about the wavelength and the intensity of the adsorption. Uma Shanker, in Green Functionalized Nanomaterials for Environmental Applications, 2022 3.4.2 Fourier transform infrared (FT-IR) spectroscopyįT-IR spectroscopy involves various phenomena such as the adoption, reflection, and emission of light using the sample ( Lin et al., 2014).
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