A SIGNIFICANT portion of all thermoplastics, thermosets and elastomers are compounded and reinforced with fillers and fibres, both for cost reasons and also to obtain specific properties in the final product. Filler modification is used for a number of reasons, the main ones being:to aid filler production (filtering, drying etc).to decrease filler water adsorptionto improve filler stability (eg. Carbonation resistance)to improve filler flow characteristicsto improve wetting and dispersion during compoundingto reduce compound viscosityto improve mechanical, electrical, fire retardant and other properties.There are two classes of modifier: those that bond to the filler surface, but not to the polymer matrix, and those that bond to both filler and polymer, tyin the two together. The latter are generally referred to as coupling agents. The classic non-coupling types are saturated fatty acid based, while organosilanes are the classic coupling agent types.
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