Thermal degradation, synthetic

In addition to natural materials, synthetic polymers might also be present in works of art. Since the end of the nineteenth century, synthetic polymers have been produced and used in the field of cultural heritage, to restore works of art [3], but also as paint binders, such as alkyd resins and acrylic water dispersions. Most synthetic polymers can be detected by GC/MS only through thermal degradation followed by GC/MS [4,5] (Chapter 12 deals with the characterisation of synthetic resins in detail). 

Amorphous Films. An amorphous film is generally prepared by solvent evaporation of a dry organic solution of Chi on a solid substrate surface. The vacuum sublimation technique, which is widely employed for most synthetic dyes, is not applicable to Chi due to possible thermal degradation of the pigment. 

In this case, water is sprayed on sawdust instead of a synthetic binder. Hot-pressing of the mat is carried out to partially hydrolyse some macromolecules contained in the wood as well as thermal degradation of free sugars and other small molecules. The degradation products contribute to the cohesion of the particles. 

The author and a co-worker later exploited 3 mm NMR probe capabilities in a study of the thermal degradation products of the oxazolidinone antibiotic Zyvox (linezolid, 41) based on the use of H-15N heteronuclear shift correlation experiments.127 In a study of the structure-function relationships of a new growth hormone-releasing peptide, ghrelin, Bednarek and co-workers128 at Merck utilized micro-probe capabilities in the characterization of the structures of the minimum sequence of ghrelin necessary for activity. As a result of these efforts, a small spiroindan, MK-0677 (59) with oral bioavailability was found to be one of the most potent synthetic analogs with this activity. 

T. Sawaguchi et al. Studies on thermal degradation of synthetic polymers. 12. Kinetic approach to intensity function concerning pyrolysis condition for polyethylene., Industrial and Engineering Chemistry. Process Design and Development, 19, 174-179 (1980). 

This book has two main parts, and the material is organized in chapters and sections. The first part of the book has five chapters including an introduction, a discussion on physico-chemistry of thermal degradation of synthetic polymers, a short discussion on instrumentation used in analytical pyrolysis, a chapter discussing what type of information can be obtained from analytical pyrolysis, and a chapter dedicated to the applications of analytical pyrolysis for the analysis and characterization of synthetic polymers. The chapter on applications includes only a few selected examples from the multitude existent in literature, and it is not intended to be exhaustive. Excellent monographs, such as F. W. Billmeyer Jr., Textbook of Polymer Science, J. Wiley, New York, 1971 H. FI. G. Jellinek, ed.. Aspects of Degradation and Stabilization of Polymers. Elsevier, Amsterdam, 1980 S. A. Liebman, E. J. Levy, ed. Pyrolysis and GC in Polymer Analysis. M. Dekker, New York, 1985 and T. P. Wampler, ed., Applied Pyrolysis... 

Th e thermoanalytical techniques have been used with great success in the field of synthetic fibers, and have been applied to studies of cellulose. For the latter, pyrolysis Avas found to be best conducted in a nitrogen atmosphere, to avoid the poor curves caused by overlapping reactions that occur in an oxidizing atmosphere. The effect of various potential fire-retardants on the thermal degradation of cellulose has also been studied successfully in this way. However, in the starch field, unfortunately, these valuable techniques have not yet been applied with sufficient care and attention paid to those complicating factors already outlined. 

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