Polymer product analysis/characterization stability

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. 

Characterization of the thermal stability of macromolecules implies the determination of the rate of volatilization and analysis of the volatile products formed, as well as the determination of the molecular weight of the residue. It must be stressed that main-chain scission involving deterioration of the physical properties of the polymer may occur in some cases without appreciable volatilization. In other cases, some volatilization does not critically limit the use of polymer systems. 

Most plastic products contain additives or other components, whose purpose is to modify the properties of the base resin, change its appearance, or lower the cost. Blends of more than one polymer are common, and composites contain inorganic fillers. Additives are incorporated into polymers for many reasons, such as altering transition temperatures, improving stability, or enhancing surface properties. NMR is very useful for characterizing the composition of blends, and solid-state techniques provide insight into compatibility and phase structure. Since NMR s sensitivity is limited, its utility for filler and additive analysis is limited, as they are often used at very low (pg/g) levels. In specific cases, however, NMR can be useful even for these components. 

The thermal stability of a material is characterized mainly by thermogravi-metric analysis (TGA), where the sample mass loss due to volatilization of degraded by-products is monitored as a function of temperature. Usually, polymer-LDH nanocomposites have enhanced thermal stability compared with virgin polymers and conventional composites because the well-dispersed LDH layers can act as a superior thermal insulator and mass transport barrier to the volatile products generated during decomposition. 

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