Thermal Decomposition of Energetic Materials 37. SMATCH/FT-IR (Simultaneous MAss and Temperature CHange/FT-IR) Spectroscopy

1990 ◽  
Vol 44 (4) ◽  
pp. 701-706 ◽  
Author(s):  
M. D. Timken ◽  
J. K. Chen ◽  
T. B. Brill
1997 ◽  
Vol 15 (2) ◽  
pp. 108-125 ◽  
Author(s):  
Karen Kinsella ◽  
James R. Markham ◽  
Chad M. Nelson ◽  
Thomas R. Burkholder

Decomposition products of fiberglass composites used in construc tion were identified using Fourier transform infrared (FT-IR) spectroscopy. This bench-scale study concentrated on identification and quantification of toxic species. Identifying compounds evolved during thermal decomposition provides data to develop early fire detection systems as well as evaluate product fire safety performance. Material fire behavior depends on many factors. Ventila tion, radiant heat flux, and chemical composition are three factors that can be modeled. Physical observations of composites during thermal decomposition with simultaneous identification and quantification of evolved gases offer re searchers in both material development and fire safety an advancement in the state-of-the-art for material testing. Gas analysis by FT-IR spectroscopy iden tified toxic effluent species over a wide range of composite exposure tempera tures (100 to 1000 ° C), during pyrolysis and combustion. Fiberglass composites with melamine, epoxy, and silicone resins were profiled. Formaldehyde, meth anol, carbon monoxide, nitric oxide, methane, and benzene were identified by the spectral analysis prior to physical evidence of decomposition. Toxic concen trations of formaldehyde, carbon monoxide, nitric oxide, ammonia, and hydro gen cyanide were observed as thermal decomposition progressed.


1997 ◽  
Vol 51 (3) ◽  
pp. 423-427 ◽  
Author(s):  
G. K. Williams ◽  
T. B. Brill

An evaluation is made about whether T-jump/FT-IR spectroscopy can be used to determine the decomposition kinetics (Arrhenius Ea and ln A parameters) of energetic organic peroxides at high temperature following very rapid heating. Polystyrene peroxide (PSP) and benzoyl peroxide were investigated, but PSP was chosen for detailed study because of its known, simple, decomposition process. The shape of the control voltage trace of the Pt filament yields kinetic constants which are reasonable for O–O bond homolysis as the rate-determining step: Ea = 39 kcal/mol, ln ( A, s−1) = 45.9. These Arrhenius parameters differ from values measured by other methods, but it is found that an isokinetic temperature of 400 ± 20 K exists for all measurements. Thus, all the kinetic measurements appear to reflect the same dominant process (O–O homolysis), but their differences make extrapolation of the rates from the temperature range of measurement to another range inaccurate.


2002 ◽  
Vol 80 (5) ◽  
pp. 455-461 ◽  
Author(s):  
A Ionescu ◽  
N Piétri ◽  
M Hillebrand ◽  
M Monnier ◽  
J P Aycard

The photochemical and thermal behavior of maleic anhydride 1a and dichloromaleic anhydride 1b, in cryogenic matrix were investigated by means of FT-IR spectroscopy. The ketenylcarbenes represent the key intermediate in the decomposition processes of the anhydrides, even if they were not observed experimentally. The yields of the different products depend on the thermal or photochemical reaction conditions. The main photochemical products obtained from 1a were cyclopropenone and acetylene, whereas the major products from 1b were dichlorocyclopropenone and dichloroacetylene, along with small quantities of dichloropropadienone. The thermal reaction leads to dichloro propa dienone, CO, and CO2. MO calculations performed at the HF/6-31G*//HF/6-31G* level support the experimental mechanisms.Key words: photolysis, thermolysis, ab initio calculations, cryogenic matrix, ketenylcarbenes.


Author(s):  
Maciej Strzempek ◽  
Karolina A. Tarach ◽  
Kinga Góra-Marek ◽  
Fernando Rey ◽  
Miguel Palomino ◽  
...  

Abstract In this article the results of the statistical MC modelling corroborated by the FT-IR spectroscopy and gravimetric adsorption studies of the low aliphatic hydrocarbons in ZSM-5 (Si/Al =28 or...


2021 ◽  
Vol 22 (4) ◽  
pp. 2191
Author(s):  
Jing Huang ◽  
Nairveen Ali ◽  
Elsie Quansah ◽  
Shuxia Guo ◽  
Michel Noutsias ◽  
...  

In recent decades, vibrational spectroscopic methods such as Raman and FT-IR spectroscopy are widely applied to investigate plasma and serum samples. These methods are combined with drop coating deposition techniques to pre-concentrate the biomolecules in the dried droplet to improve the detected vibrational signal. However, most often encountered challenge is the inhomogeneous redistribution of biomolecules due to the coffee-ring effect. In this study, the variation in biomolecule distribution within the dried-sample droplet has been investigated using Raman and FT-IR spectroscopy and fluorescence lifetime imaging method. The plasma-sample from healthy donors were investigated to show the spectral differences between the inner and outer-ring region of the dried-sample droplet. Further, the preferred location of deposition of the most abundant protein albumin in the blood during the drying process of the plasma has been illustrated by using deuterated albumin. Subsequently, two patients with different cardiac-related diseases were investigated exemplarily to illustrate the variation in the pattern of plasma and serum biomolecule distribution during the drying process and its impact on patient-stratification. The study shows that a uniform sampling position of the droplet, both at the inner and the outer ring, is necessary for thorough clinical characterization of the patient’s plasma and serum sample using vibrational spectroscopy.


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