Controlled thermal degradation

Recently, MS combinations have been available including the thermogravimetric analysis mass spectroscopy (TG-MS) combination developed by Carraher that allows the continuous characterization of evolved materials as a polymer undergoes controlled thermal degradation. 

By controlled thermal degradation of PIB, end-reactive oligomers can be prepared (53). For example, the resulting end-reactive polymers having one or two tertiary chloro groups can be converted to terminal-unsaturated polymers bearing an isopropenyl group by dehydrochlorination... 

Controlled thermal degradation of higher molecular weight aliphatic esters generates an alkene and an acid (950c, 3294). 

PyMS is capable of generating useful data on intact foodstuffs or associated microorganisms (food poisoning bacteria, for example). PyMS is based on the controlled thermal degradation of samples under inert conditions to produce mixtures of volatile compounds that are swept into the mass spectrometer ion source and ionized by El or Cl. The resulting fingerprint spectrum of the analyte contains characteristic features that can be classified by chemometric methods. Pyrolysis is sometimes combined with GC-MS in order to extract more information from the analyte. Applications of PyMS in the food sciences include quality assurance and authentication of food and drinks, analysis of cell wall material in food plants, and identification of food microorganisms. 

A technique for the controlled thermal degradation of polysaccharides by Curie-point pyrolysis with analysis of the pyrolysis products by field ionization m.s. has been developed. Integrated ion recording by photographic detection gives reproducible fingerprints in a method which appears to be a useful tool for the characterization and identification of microgram quantities of polysaccharides. 

Controlled thermal degradation of polyolefins in the presence of peroxides has been carried out in extruders or in continuous mixers, to reduce polymer MW and sample polydispersity. The resulting material has more processing advantages than the undegraded one. Based on the same principle, random chemical functionalization of polyolefins with polar groups has been achieved by extruding the polymer in the presence of peroxy ketals or peroxy esters [29]. 

Commercial pyrolyzers are available for the controlled thermal degradation of materials which are difficult to prepare for transmission spectroscopy because of toughness, surface texture, or composition, including certain polymers and rubbers.Carbon-filled rubbers are best identified by this technique. The condensate from the destructive distillation process can be collected on a plate and run by transmission or internal reflection techniques or the gas formed in the chamber can be run directly. The condensate spectra from pyrolysis should be compared with a library of pyrolyzates since they may differ somewhat from that of the starting material. Polymer pyrolyzates, for example, may show new monomer bands whereas any inorganic fillers originally present will be missing. 

Farres [11] used direct pyrolysis linked to EGA to characterise the degradation products of polyethylene oxide. Because of C-O and C-C bond scissions, backbone scission was shown to occur on pyrolysis. Also small molecules such as ethyl ether and acetaldehyde resulted from controlled thermal degradation. 

Controllable Thermal Degradation of Thermosetting Epoxy Resins... 

Ghanbari A, Heuzey MC, Carreau PJ, Ton-That MT. A novel approach to control thermal degradation of PET/organoclay nanocomposites and improve clay exfoliation. Polymer 2013 54 1361-1369. 

In currently evolved compositions, recycling and disposal present no special difficulties because thermally degradable binders are used. Ideally, the binders undergo controlled thermal degradation so that the material can be easily removed from explosive casings for the purpose of efficient recycling of the base explosive or low pollution disposal of the entire item. 

PAN homopolymer fibers are also used to produce carbon fibers utilized in composite materials. The process involves a controlled thermal degradation that begins with an intramolecular cyclization... 

This combination is an example of the precolumn arrangement. Pyrolysis/GC combines a controlled thermal degradation of a sample with the subsequent separation of neu-... 

Analytical pyrolysis (the controlled thermal degradation of organic or inorgcuiic materials with the subsequent... 

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