UNDER-THE-BONNET

The markets for polyetherimides arise to an extent from stricter regulations concerning flammability and smoke evolution coupled with such features as high strength, toughness and heat resistance. Application areas include car under-the-bonnet uses, microwave equipment, printed circuit boards and aerospace (including carbon-fibre-reinforced laminated materials). The polymer is also of interest in flim, fibre and wire insulation form. 

Reductionism is the direction that unites those guys who try to dissemble the parts of a biological system, and put them under a microscope (a laser-scanning quantum-leaping one, of course) to see the sparks of imagination hidden in the least of the components. The under-the-bonnet view, to stay with the Martian s analogy. 

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. 

It is rare for plastic components to be exposed to a single temperature during their entire service life. An under-the-bonnet component, such as a radiator end-cap, injection moulded from glass-fibre reinforced polyamide 66 could undergo a temperature profile during its service life such as the one displayed in Table 2.5. 

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

Companies can resolve their sourcing problems by developing their own infrastructure for collection. These collection schemes typically involve customers who supply dean and relatively homogeneous material which can be made into useful products [23, 24]. One example is the DuPont Partnership for Carpet Reclamation, which recovers nylon carpets from carpet companies for mechanical and chemical recycling. This scheme generates material approved for under-the-bonnet automotive applications. 

DuPont recovers used nylon carpets and converts them into new raw material either by mechanical or chemical recycling. The mechanically recycled material has already been approved for high-performance applications such as fan shrouds and other under-the-bonnet automotive applications. The chemical process generates virgin-quality material with up to 50% recycle content to give a new carpet fibre with the same wear resistance, stain resistance, and dyeability as the virgin material. 

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). 

Nylon resins have their primary applications in under-the-bonnet automotive applications and in durable goods, while nylon fibres are primarily used in textiles and carpets. These are all applications of lower volume compared to commodity plastics, with more or less complex material composition, and with disposal patterns that make them difficult to be recovered economically in sufficient amounts. 

The material generated by this separation process has been approved for direct production of some grades of engineering resins for the manufacture of fans shrouds and other under-the-bonnet automobile parts by the American automotive industry. 

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... 

Increasing sophistication under the bonnet usually means new opportunities for plastic connectors, with ever harsher temperature conditions, beyond the capability of PA 66. This is an area where several performance materials compete, notably PPS, PES, PEI, PA 46 and semi-aromatic PA. 

R J Murchie, Plastics under the bonnet their future trials and tribulations (1984). 

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

These materials are used for high-performance electrical and electronic parts, under-the-bonnet motor applications, etc. 

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