Thermal degradation infrared spectroscopy,

A comprehensive review of compositional and failure analysis of polymers, which includes many further examples of analysis of contaminants, inclusions, chemical attack, degradation, etc., was published in 2000 [2], It includes details on methodologies, sampling, and sample preparation, and microscopy, infrared spectroscopy, and thermal analysis techniques. 

The oxidation and degradation of small hydrocarbon molecules have many similarities (Fig. 8.10). These reactions have been studied extensively by a variety of surface techniques such as Thermal Desorption (TDS), ion mass spectroscopy, specular infrared spectroscopy, Secondary Ion Mass Spectroscopy (SIMS), X-ray Photoelectron Spectroscopy (XPS), and so on. The reaction pathways and the final products depend on the type of oxygen-bearing species, which in turn depends on the doping and morphology of the oxide layer. This is the major reason why results obtained with different oxide sensors in different laboratories do not always agree. 

Ageing and thermal degradation of crosslinked nadimide end-capped oligomers have been studied by means of solid infrared 13C NMR spectroscopy as well as by thermogravimetric measurements. They are mainly related to PMR and BBN families. 

Holland, B. J. and Hay, J. N. The kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopy. Polymer 2001 42 4825. 

Usami, T., Itih, T., Ohtani, H., Tsuge, S. (1990) Structural study of polyacrylonitrile libers during oxidative thermal degradation by pyrolysis-gas chromatography, solid state 13C Nuclear magnetic resonance and Fourier transform infrared spectroscopy, Macromolecules 23, 2460-2465. 

Comparison of several techniques (namely Fourier transform infrared spectroscopy (FTIR), simultaneous thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) and ultrasonic spectroscopy) for assessing the residual physical and mechanical characteristics of polymer matrix composites (PMCs) exposed to excessive thermal loads showed the measured power spectra of ultrasonic energy to correlate with performance of graphite fibre epoxy matrix composites exposed to thermal degradation, and also that analyses with the three techniques all pointed to the same critical temperature at which thermally induced damage increased sharply [58],... 

The surface chemistry of carborane (C2B10H12) and decaborane (B10H14) on Pt(lll) has been studied with reflection absorption infrared spectroscopy (RAIRS), temperature programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). It is found that the Pt surface catalyzes the release of hydrogen from both molecules at temperatures much lower than their thermal decomposition temperatures. The thermal degradation of these two molecules was found to occur in stages as shown by the TPD results. From XPS data, it was concluded that boron remains on the surface up to very high temperatures. 

In contrast to polymerisates, polycondensates can not be depolymerized under inert conditions. Decomposition usually leads to the destruction of the chemical structure and the monomers. The thermal decomposition of PET starts at about 300°C in an inert atmosphere [25]. Between 320 and 380°C the main products are acetaldehyde, terephthalic acid, and carbon oxides under liquefaction conditions. The amounts of benzene, benzoic acid, acetophenone, C1-C4 hydrocarbons, and carbon oxides increase with the temperature. This led to the conclusion that a P-CH hydrogen transfer takes place as shown in Eigure 25.8 [26]. Today the P-CH-hydrogen transfer is replaced as a main reaction in PET degradation by several analytic methods to be described in the following sections. The most important are thermogravimetry (TG) and differential scanning calorimetry (DSC) coupled with mass spectroscopy and infrared spectroscopy. 

Figures 8.2 and 8.3 show stacked curves obtained by TG-Fourier transform infrared spectroscopy (FTIR) of KL measured in air and nitrogen. TG-FTIR measurements were carried out using a Seiko TG 220 themogravimeter equipped with a JASCO FTIR7000 spectrometer [44,45,49,50]. Sample mass was 10 mg and heating rate was 200°C/min. Airflow rate was controlled at 100 mL/min. The gases evolved during the thermal degradation of KL were simultaneously analyzed by FTIR. Spectra were recorded at 30-second intervals each spectrum is the average of 10 one-second scans. The spectral resolution was 1 cm...

In blends composed from syndiotactic PS and PPE, it was discovered that the PPE destabilizes the PS somewhat in the thermal degradation region. Infrared (IR) spectroscopy indicates that PPE undergoes a rearrangement in which the ether link is broken and the chain is regenerated by the methyl group before mass loss is visualized. 

Liang and Shi [1] used Fourier-transform infrared spectroscopy and direct pyrolysis -mass spectrometry to elucidate the thermal degradation mechanism of these polymers. 

Many impurities are present in commercial caprolactam that pass into the liquid wastes from polycaprolactam (PCA) manufacture from which caprolactam monomer may be recovered. Also, the products of the thermal degradation of PCA, dyes, lubricants, and other PCA fillers may be contained in the regenerated caprolactam. Identification of the contaminants by infrared (IR) spectroscopy has led to the detection of lower carboxylic acids, secondary amines, ketones, and esters. Aldehydes and hydroperoxides have been identified by polarography and thin-layer chromatography. 

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