UNDER-THE-BONNET APPLICATION

Ozone attacks double bonds within polymer chains to form unstable ozonides which further degrade the chains. This type of degradation is predominant for under-the-bonnet applications where ozone formation can be significant. 

Temperature exposure during useful life of under-the-bonnet application. 

As an example of the complexity of organisational issues associated with Life Cycle Engineering, Figure 6.1 shows the possible stakeholders in a recycling scheme of an automotive under-the-bonnet application, in this case a radiator end-cap made from a reinforced polymer, short glass fibre-reinforced polyamide 66 (PA 66 + GF). 

The mechanical properties of importance in critical engineering applications include stiffness, rigidity, impact and impact strength, flexural modulus, elongation and include applications in areas such as gears, piping, automotive under the bonnet applications, aircraft and aerospace engineering power transmissions equipment, structural components and so on. 

A 40% addition of mineral to PA 6,6 is used for automotive under the bonnet applications whilst a 45% addition of mineral and glass fibre to PET is used in... 

PES and PPS are, amongst others, being used in the manufacture of aircraft, in high temperature under-the-bonnet applications, in medical equipment that requires sterilisation and in critical packaging applications and in the electronics and telecommunications industry. 

A wide range of plastics are now being used in interior, exterior and under the bonnet applications in the manufacture of automobiles. Some of the major applications are shown in Table 6.1. 

PP, 20% talc filled Stiffness at elevated temperatures, automotive under the bonnet applications, air ducting channels Electrical systems housing Housing for electric kettles... 

PP, 20% glass fibre filled Automotive under the bonnet applications Cooling system expansion tanks Washing machine components... 

M Trueman and F Neutens, Under the bonnet applications of engineering thermosets (1990). 

Typical underhood (engine compartment, under-the-bonnet) applications... 

High heat grades for electrical and automotive under-the-bonnet applications. 

Polyamide is used in all of the main automotive application areas. Under-the-bonnet applications is by far the largest area of application followed by electrical and lighting systems, exterior and interior applications. 

The main under-the-bonnet applications for polyamide include the air intake manifold, the air and cooling systems, peripherals, throttle body housing, the cylinder head cover, the water-glycol circuit and engine parts. High performance PA is also used to make tubing for under-the-bonnet applications such as fuel systems. 

Metal replacement has been a main driver for the use of polyamide in automotive applications in the past. Most of the obvious replacement of metal by PA has already taken place in the car interior, exterior and electrical systems areas. Under-the-bonnet applications however still offer some scope for further penetration by polyamide, particularly for high-performance grades. 

Exterior parts account for just over a quarter of the total volume of ABS used in the automotive market. The principal applications are wheel trim, mirror and light housings. ABS can also be found, usually in combination with polycarbonate as a blend, in electrical systems housing. The material is rarely found in under-the-bonnet applications because of its lower temperature resistance compared with other polymers. 

Electronic components and housings is the main applications area for PBT in the automotive sector accounting for over 60% of total volume. Exterior applications are the next most important market, followed by interior applieations. PBT has only limited use in under-the-bonnet applications. 

Under-the-bonnet applications is the smallest area of application for PBT in automotive. Typical applications include parts for the earburettor. 

Automotive is the largest market for PEEK pol5miers accounting for 41% of total world volume in 2002. PEEK is one of the leading high-performance plastics that are replacing metal for under-the-bonnet applications. 

Polyamide is used for the manufacture of tubes for protection of wire and cables. Due to its high temperature resistance, flexibility and chemical resistance, PA tubes are mainly used in automotive under-the-bonnet applications. 

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