Strain Induced Memory and Variation in the Tensile Behavior and Property of Spider Major Ampullate Gland Silk

There is a close relationship between the shape change of fiber materials and their mechanical properties. In the nature, spider silk is repeatedly stretched during performing biological functions, but the shape strain and time effect on structure and tensile behavior properties after stretching by constant elongation is rarely reported. Therefore, the effects of interval and deformation on the mechanical behavior and properties of spider major ampullate gland silk (abb.Mas) were investigated via METS electronic universal testing machine. The results show that the tensile behavior curves of spider Mas whether natural or dried by maximum supercontraction overlap well after stretched over the yield point and even over yield region to the hardening region, the previous mechanical behavior can be reproduced without the influence of the previous stretching history only via being stretched once after long interval (≥20 min) and that spider Mas presents a good shape and mechanical behavior memory of longitudinal stretching. The elastic modulus, yields stress, energy absorbed and energy dissipated in each cycle were computed by performing a series of loading-unloading tests at increasing values of strain and subsequent analysis of the true stress-true strain curves obtained from these cycles in order to evaluate the microevolution of these mechanical parameters with the cycles. It was found that this variation in the mechanical performance of spider silk can be accounted through a combination of irreversible and reversible deformation micromechanisms in which the viscoelasticity of the material plays a leading role. These findings and a new field of research may be helpful to guide the biomimetic design of novel fiber materials. © 2023 Cailiao Daobaoshe/ Materials Review. All rights reserved.