Abstract: China-made poly(phenylene ether ketone)(PEK-C)is an amorphous high-performancethermoplast with glass transition temperature 231℃, and tensile modulus 2.43GPa, tensilestrength 101 MPa and elongation at break 6.1% at room temperature. Single edge notchedspecimens were used to measure fracture toughness K_1c and critical strain energy releaserate G_1c in terms of linear elastic theory as well as critical J-integral value J_1c in termsof elastic-plastic theory. The values of K_1c, G_1c and J_1c for PEK-C are, respectively,2.34 MPa√m, 2.1 kJ/m² and 2.76 kJ/m² compared wih K_1c 2. 86 MPa√m and G_1c 2. 07kJ/m²for PEEK of ICI and K_1c 1. 96 MPa√m and G_1c 1 kJ/m² for PEKK of DuPont.

Key words: polyphenylene ether ketone, fracture toughness, fracture