Increase (Tensile, Compressive,Flexural ) Strength , Increase rigidity, creep resistance hardness and decrease thermal expansion co-efficient, elongation at break.
Minerals such as talc, calcuim carbonate, mica – increases the compound rigidity, improve the temperature resistance and reduces shrinkage & warpage.
Coupling Agents These are used to increase the adhesion between polymer & filler, fiber by covalent bonds. Ex: Methacrylato-chromo chloride used for glass fibres & Polyester resin Organosilanes are used for PVC , ABS and PA
Blowing agents are also known as foaming agents. Upon heating liberate Gas
Are used to produce porous polymers i.e. cellular/foam plastics.
Blowing Agents Physical Blowing agents : Nitrogen & CO 2 inert gas- Low cost, No solid residue Trichlorofluromethane – PU foam Pentane and Heptane - PS foam Chemical Blowing agents: High temp, Azo Dicarbonamide decompose on heating to produe free radicals and N 2 gas