Cryogenic properties of polymer materials

Abstract

The cryogenic properties of polymer materials have received great attention with new developments in space, superconducting, electronic and defense technologies as well as large cryogenic engineering projects such as International Thermonuclear Experimental Reactor (ITER), etc. Polymer materials developed for these applications are mainly employed as electrical insulators, thermal insulators, vacuum sealants, and matrix materials for composites used in cryogenic environments. The requirements are extremely severe and complicated for polymer materials in these unique applications. The polymer materials need to possess good mechanical and physical properties at cryogenic temperatures such as liquid helium (4.2 K), liquid hydrogen (20 K), liquid nitrogen (77 K), and liquid oxygen (90 K) temperatures, etc., to meet the high requirements by the cryogenic engineering applications. Herein the cryogenic mechanical and physical properties of polymer materials will be highlighted in this chapter. Cryogenic tensile properties/behaviors are first presented in some details for various neat polymers and filled polymers. Cryogenic shear strength, impact strength, and fracture toughness are then discussed. Afterwards, cryogenic thermal, creep, sliding, and dielectric properties of polymers are briefly summarized. Finally, discussions about effects of water absorption and cryogenic aging on cryogenic properties of some polymers are conducted.