Polymer product analysis/characterization degradation

This book is divided up into sections. The first three chapters provide a background sections that follow contain chapters dealing with polymer chain analysis, polymer morphology and structure, polymer degradation, polymer product analysis and support techniques. These are listed in more detail in Chapter 1, which also expands more fully on our industrial perception of the requirements for competence and appreciation in all techniques and methods for polymer molecular characterization and analysis. We hope you find this book of value and its approach both unique and technically informative and useful. 

The characterization of relatively complex polymers is usually carried out by means of coupled techniques because sometimes a single technique is not enough to elucidate their structures. Pyrolysis of polymers is an old technique used many years ago to identify materials by their vaporized decomposition products. The coupling of this simple method with a powerful identification technique, such as infrared (IR) spectroscopy or, often, mass spectrometry (MS), has demonstrated its utility for the analysis of polymeric materials and, mainly, for the characterization of their degradation products. 

The lack of definitive studies is due to a mixture of reasons including 1) wide variety of polymers 2) newness of interest in the area 3) wide variety of applications (both potential and actual) of inorganic and organanetallic polymers not requiring thermal stability or thermal analysis (uses as anchored metal catalysis, control release agents, electrical and photochemical applications, speciality adhesives) 4) insufficient description, identification, of the products 5) wider variety of degradation routes and other thermal behavior in comparison to organic polymers and 6) many products were synthesized and briefly characterized before the advent of modern thermal instrumentation. 

The worldwide investigation of new silicon-containing polymers as innovative high-tech materials requires the development of modem analytical techniques. The methods should allow the characterization of the starting compounds as well as a comprehensive analysis of the main and by-products with regard to their molar masses and molar mass distribution. Precise information on the distribution of the chemical constituents and functional groups is also needed in order to understand polymer formation processes, degradation behavior, and stmcture-property relationships. 

The phenomenon of pyrolytic scission into a large number of degradation products can be used, on the other hand, to characterize the original polymer. If the pyrolysis is carried out under standard conditions, then the degradation products of every polymer yield a characteristic fingerprint, e.g., in combination with gas chromatographic analysis. The procedure is therefore very suitable for the industrial quality control, and may also be used in clarifying polymer structure (sequence, etc.). 

DSC is often used in conjunction with TA to determine if a reaction is endothermic, such as melting, vaporization and sublimation, or exothermic, such as oxidative degradation. It is also used to determine the glass transition temperature of polymers. Liquids and solids can be analyzed by both methods of thermal analysis. The sample size is usually limited to 10-20 mg. Thermal analysis can be used to characterize the physical and chemical properties of a system under conditions that simulate real world applications. It is not simply a sample composition technique. Much of the data interpretation is empirical in nature and more than one thermal method may be required to fully understand the chemical and physical reactions occurring in a sample. Condensation of volatile reaction products on the sample support system of a TA can give rise to anomalous weight changes. 

Unfortunately, none of the hyperbranched polymers smdied to date has demonstrated good mechanical properties. A hyperbranched PC is also expected to be a brittle material, but such a stmcture may prove interesting as a highly functionalized prepolymer for composites, coatings, and other applications. Hyperbranched PCs were synthesized and characterized by Bolton and Wooley. ° The products were prepared by the polymerization of an A2B monomer derived from l,Ll- nT(4 -hydroxyphenyl)-ethane. Silylation of the phenol terminated material with rert-butyldimethylsilyl chloride, followed by degradation of the carbonate hnkages by reaction with lithium aluminum hydride and analysis of the products by HPLC... 

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