Tensile, fracture and thermal properties of polyarylates at room and cryogenic temperatures.

The results show an increase in both the modulus of elasticity and the ultimate tensile strength by about a factor of two on decreasing the temperature to 77 K. Further cooling to 4.2 K leads to a decrease of about 10% in these properties. On the other hand, the ultimate tensile strain of ISARYL 15X decreases by about 65% at 4.2 K, whereas a non-uniform temperature dependence is found for ISARYL 25X. The fracture toughness of both materials increases by about a factor of three upon decreasing the temperature to 77 K, but decreases by a factor of two at lower temperatures. These results are discussed in conjunction with additional observations of the fracture behaviour made with optical and scanning electron microscopes.