FILLERS IN COMMERCIAL POLYMERS

Several aspeets of this discussion are common to all polymers. These include the major applications of polymers, the most common methods of polymer processing, the most frequently used fillers and their typical concentrations, additives used to incorporate fillers, special methods of filler incorporation, fillers pre-treatment, and special considerations affecting the selection of a filler. These data found in the most recent literature are recorded in a tabular form for clarity and ease of comparison. This is followed by some examples of current use of fillers in particular polymers. The examples can be used to develop numerous new applications for fillers in material improvement. They elaborate on the most recent developments in filler and filled material improvements. 

The application of polymer affects choice of filler. For example, to prepare conductive materials, special fillers must be used to obtain the required properties. Also, the method of processing imposes certain constraints on the choice and treatment of the filler before its use. For example, polymers processed at high temperature require fillers which do not contain moisture. This affects both the choice of the filler and/or its pretreatment. The choice of additives used to improve the incorporation of the filler depends on the application and the properties required from a product but it is also determined by the processing method. For example, the viscosity of a melt is reduced by special lubricating agents whereas the viscosity of filler dispersions is controlled by the surface treatment of filler. In some cases, the order of addition is important or a special filler pretreatment is used to achieve the desired results. These methods are discussed in special section in the table. Some fillers simply caimot be used with some polymers. In other cases, special care must be taken to ensure polymer stability or filler may interact with some vital components of the formulation. This subject is discussed in special considerations of filler choice. 

Major polymer applications paints, coatings, roofing, sealants, elastomers, fibers, industrial filters, battery separators, carbon and graphite fibers, ceramics 

Important processing methods mixing/compounding, extrusion, calendering, Banbury mixer, vulcanization, wet and dry spinning 

Typical fillers calcium carbonate, titanium dioxide, fumed silica, zinc oxide, carbon black, aluminum silicate, graphite, ceramic microspheres 

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