Corrosion and preservation of the Apollo spacesuits

This project involved the first detailed examination of the condition of the Apollo spacesuits since their acquisition by the National Air and Space Museum, Washington DC, USA in the 1970s. Plasticized polyvinyl chloride (PVC) tubing used to transport air and water to the astronaut in the Life Support System, and to cool the wearer of the spacesuit in the Liquid Cooling Garment, exhibited high levels of deterioration. Tubing was unacceptably discoloured, tacky to the touch and its surfaces obscured by crystals. Visual examination, Fourier Transform infrared spectroscopy and Low-Vacuum scanning electron microscopy suggested that discolouration was a result of dehydrochlorination of the PVC polymer, tackiness was caused by migration of the di (2-ethylhexyl) phthalate (DEHP) plasticizer to surfaces and the formation of phthalic acid crystals at surfaces was a result of hydrolysis of the ester groups in DEHP. Based on the research into the factors which influence the rate of deterioration of plasticized PVC, it seems likely that enclosing the Apollo spacesuits and reducing their storage temperature, would enable them to be preserved for future generations.