Effect of thermal aging on the adhesive strength of joints of double-chain polymers with fibers and on the properties of unidirectional CFRPs based on them

The paper presents a study on the effect of thermal aging on the adhesive strength of joints of some double-chain polymers and fibers. It is shown that the initial shear strength of joints of a steel wire with double-chain polymers based on bisaminonitrile (R = −CH₂−) is significantly higher than that in the case of polymers based on the “A-B” monomer. The type of thermal stabilizer affects the strength of the fiber/matrix interface only slightly. Prolonged heating (up to 100 hours) of the joints at 350 °C does not reduce the strength of joints based on the “A-B” monomer, while that of joints based on bisaminonitrile decreases by 20-30%. The thermal stability of carbon-fiber-reinforced plastics appeared to be higher, which was likely due to the effect of scale factor. The strength of a test specimen batch decreased only upon exposure to 400 °C for more than 100 hours.