Glass-filled polymer

Glass-filled polymer, or glass-filled plastic, is a mouldable composite material. It comprises short glass-fibres in a matrix of a polymer material. It is used to manufacture a wide range of structural components by injection or compression moulding.

Either thermoplastic or thermosetting polymers may be used. One of the most widely used thermoplastics is nylon.

The first mouldable composite was Bakelite. This used wood flour fibres in phenolic resin as the thermoset polymer matrix. As the fibres were only short this material had relatively low bulk strength, but still improved surface hardness and good mouldability.

A wide range of polymers are now produced in glass-filled varieties, including polyamide (Nylon), acetal homopolymers and copolymers, polyester, polyphenylene oxide (PPO / Noryl), polycarbonate, polyethersulphone

Bulk moulding compound is a pre-mixed material of resin and fibres supplied for moulding. Some are thermoplastic or thermosetting, others are chemically cured and are mixed with a catalyst (polyester) or hardener (epoxy) before moulding.

Compared to the native polymer, glass-filled materials have improved mechanical properties of rigidity, strength and may also have improved surface hardness.

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