Plastic World

Which plastic is right for what application and how technically safe these products and construction units manufactured from plastics are can only be answered using informative measurement and test methods. The Federal Institute for Materials Research and Testing (BAM) works on the development of methods which answer these questions. BAM presents its know-how in the field of plastics at the K 2007 fair from 24 to 31 October in Hall 4, Booth D14, in Düsseldorf.

BAM has developed highly realistic methods for simulating the degradation process of plastics in a few months using accelerated testing. For this purpose the plastics are exposed to aggressive media, e.g. diluted acids or bases, at elevated temperatures and increased pressures. So a realistic estimate for the expected life span of geosynthetics in the soil has to be provided using this method. Geosynthetics are one of a number of materials used for slope stabilisation or in road construction where the strength needed must be maintained over many decades. It is controlled by the chemical structure of the plastics which can be impaired or destroyed under the effect of water and oxygen in the soil.

An ultrasound method developed by BAM now enables the on-line monitoring and control of the hardening process of plastics which contain glass or carbon fibres. These strengthened plastics are increasingly being used because of their high mechanical load bearing capacity and their low weight in high-tech construction units in the aeronautical and space industry and in car manufacture. The construction units are produced from liquid resin at temperatures between 100 °C and 200 °C by a chemical reaction. At a given chemical composition the hardening process determines the chemical structure of the plastic. This affects strength and eventually the technical safety. Hardening time plays a crucial role: it must be neither too long nor too short. If it is too short, mechanical stability is not guaranteed. If it is too long, the product is too expensive since a long hardening time does not improves characteristics any further.

A special importance is attributed to the flame retardation of plastics under the heading of technical safety within the public realm. Work is being carried out in BAM to clarify and understand the burning and flame retardation mechanisms of plastics where thermal decomposition of plastics and pyrolysis products are investigated and the fire risk is determined. The findings should be integrated into the development of new flame-retarded products.

Information:
Priv.-Doz. Dr. habil. Andreas Schönhals,
Chairman of the BAM Working Group “Polymers”,
Division VI.5 Polymer Surfaces
Phone: +49 30 8104-3384
Email: andreas.schoenhals@bam.de