How are plastics used in the Aerospace industry?

It is fair to say that plastic has suffered a bit of bad reputations lately. The fact that it is so difficult to recycle has meant that it has been demonised in some quarters, however, it is important to remember that it is still a vital material in many industries, including aerospace.

There are many different types of plastic, and some come with huge benefits for the aerospace sector. Carbon fibre composites, reinforced polymers and thermoplastics have become firm favourites for use in civilian, commercial and military aircraft, with no obvious replacement being found.

Typical Aerospace Plastics

Plastic is most commonly found inside the aeroplane, forming parts of the air ducts, cabin partitions, floor panels and overhead luggage bins. It is also a popular choice for things such as avionics sensor plates, electronic component mounting brackets and ventilation impeller blades. Its use internally does not mean that is doesn’t feature on the outside of the plane too, with fuel tank covers, landing gear hubcaps, pylon fairings and radomes all now made out of some form of plastic.

So, what types of plastics are preferred? Acrylonitrile butadiene styrene, polyetheretherketone (PEEK) and polyphenylene sulfide are all used a wide variety of aerospace applications. There are also plastics such as polyetherimide with meet the strict flame, smoke and toxicity requirements set out by the Federal Aviation Administration (FAA).

Polyetherketoneketone (PEKK) is an advanced polymer that also offers flame retardancy as well as chemical resistance and thermal stability. Its incredible strength and low weight have meant that it is now often used in place of aluminum.

Why use plastic for Aerospace?

Many might question why there is such a use of plastic in aerospace, but the truth is that it is an incredibly versatile material that is difficult to replace with anything else quite so effective. Traditional plastics have been used for years in certain, but these are now being used in different ways, and new plastics are being created which offer specialised characteristics.

Plastic is often being used to replace metals such as aluminum because it has the enviable quality of being both light and strong. They also have the benefit of being non-corrosive and heat-resistant, making them durable and reliable, and often out-perform their metal counterparts. The fact that these plastics can be moulded into existing designs means that there are no changes to the overall design of existing parts, making the replacement of certain components easy.

Many of these plastics can also be engineered to be resistant to a number of chemicals that include jet fuel also make it difficult to ignore. A large amount of these plastic parts are also self-lubricating, which cuts down the need for grease and other petroleum-based lubricants, all of which bring their own risks with them.

Plastics are not perfect though, as some components can be more difficult to manufacture, particularly when so many engineers have spent decades working with aluminum. Plastic is also a material with low levels of conductivity which means copper mesh layers need to be added to the fuselage of an aircraft to protect it from lightning strikes. Long-term aging of these polymers is also unchartered territory, so more learning needs to be done to fully understand how these new materials will change and work over time.

However, professional plastic manufacturers such as Ansini, commented, “This essential material is at the forefront of aerospace design because of the vast number of positive characteristics it can boast. It is something that can be replicated from the very biggest planes to the smallest, and with NASA investing $15 million to continue developing new composites, the industry shows no signs of shying away from plastic any time soon.”