Saturday 20 July 2019

Take Me To The Moon – Celebrating 50 Years Moon Landing With High Performance Polymers

On July 20 1969, 50 years ago, Neil Armstrong and Buzz Aldrin touched ground on the moon. By Neil Armstrong: “That's one small step for (a) man, one giant leap for mankind.”
The Apollo 11 crew was well equipped with latest technology. This included two high performance polymers constituting their helmet visors: polycarbonate (PC) and polysulfone (PSU).

Why were polycarbonate and polysulfone used for the helmet visors?

Polycarbonate as protective helmet visor:

Polycarbonate can be regarded as the benchmark for all existing impact resistant plastics. It got its name from the containing carbonate groups (−O−(C=O)−O−) in its backbone. These promote temperature and high impact resistance as well as an amorphous macromolecular structure which leads to excellent optical properties. High energy is needed to tear its chains apart. For these reasons, an ultraviolet-stabilized polycarbonate visor was used for protecting the heads of astronauts against impact and micrometeoroids. The protective visor could be moved independently of the sun protection visor. Back then, the Apollo mission used the newly developed polycarbonate Lexan® from GE Plastics [1].

Polysulfone as sun protection helmet visor:

Polysulfone has a high service temperature (Tg = 190°C) in combination with reduced creep and dimensional stability. Among non-reinforced thermoplastics, polysulfone affords top high-temperature creep resistance. Another superior property of this plastic is that it retains its transparency after prolonged exposure to temperatures up to 200°C. This high temperature resistance property is to great extent imparted by the contained diphenyl sulfone groups. These characteristics made polysulfone suitable to be used as the sun protection visor (outer visor) in astronauts’ helmets [2,3], which main function was to protect the astronaut from sun exposure and high temperatures. For this, the inner surface of the polysulfone-based visor was also coated with gold for extended sun visor protection capabilities. The gold coating supported the protection against generated heat inside the helmet as well.

Thank you for reading this recap history!

Till next time!

best regards,
Herwig Juster

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