On the fracture of reinforced thermoplastics

In the designing of engineering fiber-reinforced thermoplastics and of the processing technology to make such, their behaviour at failure should be taken into consideration. The processes of deformation and failure from compression were investigated for polycarbonate and polyarylate reinforced with polyaramide fiber, particularly, poly- m-phenyleneisophthalamide and poly- p-amidobenzimidazole, the results obtained being described in this paper. The acoustic emission (AE) technique was used to reveal the essential dependences of the deformation and the fracture on the fiber length and elastic modulus of the composites. Chemical, plasma or biochemical pre-treatment of the fiber surface appeared to considerably influence the kinetics of damage accumulation in the material. The relationship between the interphase interaction of the components and the characteristics of the fracture surface is considered for fiber-reinforced thermoplastics. Morphological differences were established by the secondary electron emission technique using the scanning electron microscope and a computer system. The statistical characteristics of the fracture surfaces of composites differing in the fiber origin and in the degree of interaction between the components are described. The strength properties of the fiber-reinforced thermoplastics are described for quasistatic (deformation rate 10 −4 s −1) and dynamic (deformation rate 10 2 s −1) loading conditions.