Electrical glass increase shrinkage

Fillers may be divided into particulate and fibrous types. Particulates include calcium carbonate, china clay, talc and barium sulphate. Fillers affect shrinkage on moulding and the dimensional stability of the finished plastic, increase tensile strength and hardness, enhance electrical insulation properties and reduce tackiness. They also impart opacity and colour (Figure 3.16). Carbon black is now the most widely used filler for polymers usually in the form of furnace carbon black, which has a particle diameter of 0.08 mm. Fibrous fillers reinforce polymers and greatly increase their tensile strengths. They include fibres of glass, textile and carbon. Plastics filled with fibrous fillers are known as composites. 

Specifically, the reinforcement of polymers with glass fibers substantially improves mechanical properties such as strength and stiffness improves dimensional stability, mold shrinkage, and chemical resistance and improves the dc electrical properties of dielectric strength and arc resistance as well as ac dielectric constant and dissipation factor. Both increases and decreases are noted in volume resistivities. Reinforcement also reduces percent elongation and thermal expansion properties. 

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