Effect of vacuum thermo-cycling on physical properties of unidirectional M40J/AG-80 composites

The vacuum thermo-cycling (−180 to +140 °C, 10−5 Pa) was performed on unidirectional M40J/AG-80 composite. The tensile strengths at 90 and 0°, bend strength, interlayer shear strength, mass loss ratio and storage modulus (E′), as well as the transverse and longitudinal expansion/contraction distortions, were measured after different thermal cycles. The results show that the variations in the 90 and 0° tensile strengths and the longitudinal contraction distortion are closely related to the extent of interface debonding, while the changes in bend strength and transverse expansion/contraction distortion to the increase in cross-linking density in the AG-80 epoxy matrix. The mass loss ratio increases with thermal cycles and then level off after 48 cycles.