Reinforcing agents properties

Reinforcing fillers (active) Fumed Silica (Si02) precipitated calcium carbonate (CaCOi) carbon black Thixotropic reinforcing agents (non-slump), adjustment of mechanical properties (cohesion) provide toughness to the elastomer as opposed to brittle materials. 

Thermal stability is a crucial factor when polysaccharides are used as reinforcing agents because they suffer from inferior thermal properties compared to inorganic fillers. However, thermogravimetric analysis (TGA) of biocomposites suggested that the degradation temperatures of biocomposites are in close proximity with those of carbon black composites (Table-1). 

The use of inorganic additives as extenders in thermoplastic polymers is a long established practice. In recent years, the role of such additives has changed from that of cost-reducing fillers to property enhancing reinforcing agents. This conversion has come about as a result of the comp tibilization of the additive with the thermoplastic polymer, by interaction at the polymer-filler interface. 

Throughout the text we will relate polymer structure to the properties of the polymer. Polymer properties are related not only to the chemical nature of the polymer, but also to such factors as extent and distribution of crystallinity, distribution of polymer chain lengths, and nature and amount of additives, such as fillers, reinforcing agents, and plasticizers, to mention a few. These factors influence essentially all the polymeric properties to some extent including hardness, flammability, weatherability, chemical stability, biological response, comfort, flex life, moisture retention, appearance, dyeability, softening point, and electrical properties. 

Filler, in general, can be defined as finely divided particles that are often used to enhance the performance and various desirable properties of the host matrix, depending on a typical application. A great deal of research endeavors have been dedicated to the development and the use of different fillers with a dimension at the nanometer level. In rubber technology the term nano is not unfamiliar to a rubber specialist. Since the start of the twentieth century, carbon black and silica have been utilized as effective reinforcing agents in various rubber formulations for a variety of applications. The primary particle sizes of these fillers remain in the nanometer range. However, with these conventional fillers the dispersion toward individual... 

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