The property profile of a plastic can be selectively altered by introducing additives or fillers designed to achieve specific characteristics. The resulting plastic compounds allow for different (usually increased) thermal, mechanical, electrical, optical or other characteristics to be enhanced beyond what is typically seen in the unmodified base polymer. The most common fillers and additives, besides colourants, are reinforcement fibres, stabilisers, and friction reducing additives.
In fibre reinforced polymers, the reinforcement fibres determine the compound's material properties. In many cases, the strength of the fibres is greater than the matrix materials - and frequently also higher than the tensile strength of metallic materials. The density of the most commonly used fibres, in contrast, is usually lower than that of aluminium, which allows for greater potential in designing parts for lightweight construction. In most cases, glass, carbon and aramid fibres are used in fibre reinforced plastics. From the designer's point of view, the mechanical characteristics of the material are particularly important.
They can be expensive to produce, but are mostly used wherever high strength to weight ratio and rigidity are required. These modifications are frequently applied in fields like aerospace, automotive and many other technical applications.
Other fillers generally offer no or only minimal technical benefits and primarily serve to reduce cost or weight: Ensinger offers chalk, talcum, or hollow glass spheres, for example.
Ensinger also offers ceramic filled plastics in yet another innovative compound solution that increases physical properties and machining characteristics, among other things.
Molybdenum sulphide is used predominantly as a nucleating agent and forms a fine crystalline structure, even when added only in small quantities. As a result of the higher crystallinity, plastics achieve greater abrasion resistance as well as a reduced coefficient of friction. Ensinger can also offer specially formulated compounds that combine low friction additives. One example is Ensinger's PVX family of materials, which contains 10% each of PTFE, graphite and carbon fibre. The combination of PTFE and graphite gives the material excellent sliding friction properties, while the addition of carbon fibres results in higher strength and abrasion resistance. These materials also offer extremely good dry and emergency running properties under heavy load.
