Phenolic Prepregs and the Role They Play in Aerospace Design

Aerospace engineers have long relied on prepregs as a construction material. They find phenolic prepregs especially attractive because of the inherent properties found in phenolic resins. The resulting pre-impregnated fiber materials offer a perfect balance of thermal, chemical, and mechanical properties.

The Phenolic Resin

At the heart of the phenolic prepreg is the phenolic resin itself. It is a resin made with phenol, formaldehyde, and some sort of catalyst. Phenolic resins are appreciated throughout a variety of industries – including automotive, railway manufacturing, and aerospace – because of certain properties. Fire resistance is a big one.

How They Are Used in Aerospace Design

The importance of the role phenolic prepregs play in aerospace design cannot be understated. When you are talking about aircraft and space vehicles, there is no room for any compromise that could jeopardize safety. Every material choice needs to be appropriate to the need and as safe as is humanly possible. That begs the question of how phenolic prepregs are used in aerospace design.

Here are some key examples:

1. Aircraft Interiors

A typical aircraft is equipped with interior parts made with phenolic prepregs. Examples include floor and wall panels. Storage compartments and overhead luggage bins are also made with the prepregs. Their biggest advantage is fire resistance. Phenolic prepregs do not burn easily. When they do, they do not produce nearly the same volume of smoke and toxic gases that other materials produce. Passenger safety is a huge motivation here.

2. Secondary Structural Parts

Designers and engineers often turn to phenolic prepregs when designing secondary structural components. A combination of chemical resistance, self-extinguishing characteristics, and adequate adhesion make them ideal for components that are not subject to excessive mechanical loads.

3. Thermal Protection Systems

Moving beyond aircraft to space vehicles, phenolic prepregs are used extensively in rocket systems and other spacecraft. The prepregs are ideal for manufacturing components that excel at dissipating heat. More common examples include temperature of blade of rocket nozzles, combustion chambers, motor throats, and even heat shields.

Phenolic prepregs can withstand extreme heat and highly oxidative environments. They dissipate heat exceptionally well with no compromise in their structural integrity.

Phenolic Prepregs’ Key Properties

You can probably guess the properties that make phenolic prepregs so desirable in aerospace design. From the three cited examples, it is easily seen that the key properties engineers and designers love are:

• FST Performance – The fire, smoke, and toxicity (FST) performance phenolic prepregs bring to the table is excellent. Phenolic resins meet or exceed all stringent FST requirements for interior cabin materials.
• Thermal Ablation – Thermal ablation is an important characteristic in any aerospace application simply because both atmospheric and space flight require components subjected to excessive heat.
• Thermal Stability – Hand-in-hand with thermal ablation is thermal stability. Parts subject to high heat must not be subject to failure. Phenolic prepregs offer the kind of stability engineers need to design and build certain components.
• Chemical Resistance – In addition to how well they handle high heat, phenolic prepregs also offer robust chemical resistance. Some of the harshest chemicals in aerospace manufacturing are not a problem for phenolic resins.

Engineers and designers also benefit from the fact that phenolic prepregs are available in a variety of forms. Bias tapes and broad goods are just two examples. Different formats allow for maximum flexibility in the design process.

There is certainly more to aerospace design than choosing phenolic prepregs. But as far as aerospace composites go, phenolic prepregs are extremely valuable. Their contributions help make modern aerospace design what it is. We are proud to offer them here at Axiom Materials.