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Analytical Pyrolysis: An Overview
Published in Karen D. Sam, Thomas P. Wampler, Analytical Pyrolysis Handbook, 2021
Pyrolysis, simply put, is the breaking apart of chemical bonds only by thermal energy. Analytical pyrolysis is the technique of studying molecules either by observing their behavior during pyrolysis or by studying the resulting molecular fragments. The analysis of these processes and fragments tells us much about the nature and identity of the original larger molecule. The production of a variety of smaller molecules from some larger original molecule has fostered the use of pyrolysis as a sample preparation technique, extending the applicability of instrumentation designed for the analysis of gaseous species to solids, especially polymeric materials. As a result, gas chromatography, mass spectrometry, and Fourier-transform infrared (FTIR) spectrometry may be used routinely for the analysis of samples such as synthetic polymers, biopolymers, composites, and complex industrial materials.
Powder Characterization
Published in Mohamed N. Rahaman, Ceramic Processing, 2017
Fourier transform infrared (FTIR) spectroscopy is a technique that is used to measure the infrared spectrum of absorption or emission of a material [20]. When infrared radiation is passed through a sample, the chemical functional groups absorb radiation at certain wavenumber ranges due to the stretching, bending, and vibrational modes of the chemical bonds, and some of the radiation is transmitted through the sample. The resulting spectrum represents the molecular absorption and transmission, providing a molecular fingerprint of the sample. Consequently, FTIR can be used for qualitative analysis to determine the functional groups present in a sample. In addition, by determining the area of the peaks (or bands) in the spectrum, software algorithms provide the means for quantitative analysis. Figure 5.19 shows the FTIR spectra of silicate glass particles (composition 24.5 Na2O, 24.5 CaO, 45.0 SiO2, 6 P2O5; wt%) that were reacted in K2HPO4 solutions with two different concentrations but under the same conditions. The difference in the composition of the reaction product is easily seen from the FTIR spectra.
Nanoscale Characterization
Published in Ram K. Gupta, Sanjay R. Mishra, Tuan Anh Nguyen, Fundamentals of Low Dimensional Magnets, 2023
Arvind Kumar, Swati, Manish Kumar, Neelabh Srivastava, Anadi Krishna Atul
FTIR is a characterization technique used to obtain the infrared spectrum of absorption, emission, and photoconductivity of solids, liquids, and gases [56]. In FTIR spectroscopy, the process of Fourier transform is used to convert the raw data (interferogram) into the actual spectrum. FTIR spectra are important to generally identify and characterize unknown materials, attached functional groups, contaminants in material, etc. FTIR records and collects high spectral resolution data, usually between the wavenumber range 5000 and 400 cm−1 for the mid-IR region and between 10,000–4000 cm−1 for the near-IR region, having a typical resolution of 4 cm−1 [55].
Development of polypyrrole-coated cotton thermoelectric fabrics
Published in The Journal of The Textile Institute, 2023
Vivek Jangra, Prashant Vishnoi, Subhankar Maity
FTIR is an analytical technique for identifying organic and inorganic materials. FTIR involves the measurement of absorption of infrared radiation by a material at specific wavelengths. Presence of various pendent functional groups on the surface of uncoated and PPy-coated cotton fibre is identified by the FTIR analysis. Figure 11 shows FTIR spectra of uncoated cotton and PPy cotton. In the FTIR spectra of pure cotton, the band at 3618 cm−1 is due to non-bonded hydroxy group, OH stretch band at 3321 cm−1 is due to –OH stretching (Nandiyanto et al., 2019), band at 2920 cm−1 is due to methylene C–H asymmetric stretch, band at 2842 cm−1 is due to methoxy methyl ether O–CH3 and C–H stretch (Nandiyanto et al., 2019), and band at 1701 cm−1 is due to carboxyl group (Nandiyanto et al., 2019). In the FTIR spectra of PPy-coated cotton fibre, bands at 1525 cm−1 and 1457 cm−1 are found which can be attributed to Py C = C ring stretching vibration and C–C stretching vibration of PPy, respectively. There are red/blue shifts are observed in case of bands due to –CH asymmetric vibration (2920 cm−1) and β linkage (907 cm−1). Such red/blue shifts of the peaks are due to the formation of intermolecular hydrogen bonds between cellulose and PPy polymer molecules at these positions. This intermolecular hydrogen bonding depicts a significant chemical interaction between cellulose and PPy by which fixation of PPy occurs on the cotton surface shown in Figure 11.
Contributions of Fourier transform infrared spectroscopy in microplastic pollution research: A review
Published in Critical Reviews in Environmental Science and Technology, 2021
S. Veerasingam, M. Ranjani, R. Venkatachalapathy, Andrei Bagaev, Vladimir Mukhanov, Daria Litvinyuk, M. Mugilarasan, K. Gurumoorthi, L. Guganathan, V. M. Aboobacker, P. Vethamony
FTIR spectroscopy deals with measurement of infrared (IR) radiation absorbed by the MP sample, allowing the study of molecular composition. An infrared spectrum represents a fingerprint of a sample (MP) with absorption peaks correspond to the frequencies of vibration between the bonds of the atoms making up the material. Because each different polymer material is a unique combination of atoms, no two compounds produce exactly the same infrared spectrum. Therefore, the chemical structure of a polymer molecule can be determined by FTIR (Chalmers, 2006). The IR region of the electromagnetic spectrum is divided into three regions: (1) the higher energy near infrared (NIR) region with wavenumbers of 14,000–4000 cm−1 (0.78–2.5 µm wavelength) range, which is sensitive to overtone and combinations of vibrations, (2) the mid infrared (MIR) region with wavenumbers of 4000–400 cm−1 (2.5–30 µm wavelength) range to study the fundamental vibrations and (3) the far infrared (FIR) region with wavenumbers of 400–10 cm−1 (30–1000 µm wavelength) range to study rotations (Mukherjee & Gowen, 2015). Among these three IR spectral regions, MIR is the most common region in the field of MP characterization. FTIR spectroscopy can be used to study the solid, liquid and gaseous samples. Since MPs are generally solid samples, we will focus our discussion on these materials. FTIR spectra of different polymers are covered in this review to illustrate the key features involved in spectral interpretation and its application for the analysis of MPs.
Characteristic Analysis of Pulverized Coal Combustion
Published in Combustion Science and Technology, 2021
Zhilin Xi, Xiaodong Wang, Meitong Li, Xiaoli Wang
Thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) was carried out using a STA-449-F3 (NETZSCH, Bavaria, Germany) and VERTEX70v FTIR (Bruker Corporation, MA, USA), which had thermogravimetry (TG), differential scanning calorimetry (DSC) and infrared spectroscopy techniques. During the experiment, the related experimental data could be measured and recorded simultaneously by TG-FTIR, including the mass loss, mass loss rate, heat of oxidation reaction and functional groups of gases. The testing temperature was set at a range of 30–800°C with a heating rate of 10°C/min. FTIR spectroscopy was set with a scanning range of 400–4000 cm−1, a resolution of 4 cm−1 and a scanning 32 times for each test. The experiment was performed at a gas environment of oxygen/nitrogen to 1:4 with a flow rate of 50.0 mL/min. In addition, the experimental data was handled by OMNIC software, which contained the function to analyze the spectrum, peak value and absorption intensity, and achieved automatic correction of the base line, separation of spectra and integration of data. In order to ensure the repeatability of the experimental result, each experiment was carried out three times, ensuring that the difference was lower than 3%. The absorption bands of index gases were summarized in Table 2.