First evidence and characterization of strain-induced crystallization heterogeneity in natural rubber under homogeneous strain states

Strain hardening in biaxially stretched elastomers undergoing strain-induced crystallization

“…This phenomenon termed strain-induced crystallization (SIC) has been investigated by many researchers. [5][6][7][8][9][10][11][12][13][14] A noteworthy advantage of SIC is the consequent strain hardening, resulting in substantial mechanical reinforcement. Specically, the region proximate to the crack-tip undergoing high strain experiences SIC, thereby forming an effective barrier against further crack propagation.…”

“…While numerous studies have reported the effects of SIC on mechanical properties, the context is oen restricted to uniaxial tension. 11,[28][29][30][31] However, it is essential to recognize that uniaxial deformation is just one of accessible deformations of elastomers, and the experiments relying solely uniaxial deformation provide only a partial understanding of the broader nonlinear stress-strain behavior. Rubber products experience complex deformations, including unequal biaxial stretching in two orthogonal directions.…”

On the influence of the amorphous phase on the stability of crystals in poly(cis‐1,4‐isoprene) networks

“…Crystals in natural rubber (NR) networks are a good example of this polymer‐typical characteristic, 5 because they form at room temperature only under strain but spontaneously melt when the stretching force is released and the rubber retracts back to its original dimensions. This phenomenon, referred to as strain‐induced crystallization (SIC), is intensively studied since its discovery in the 1920s, because it is assumed to be responsible for the outstanding high tensile strength of NR at high elongations 6–19 …”

“…This phenomenon, referred to as strain-induced crystallization (SIC), is intensively studied since its discovery in the 1920s, because it is assumed to be responsible for the outstanding high tensile strength of NR at high elongations. [6][7][8][9][10][11][12][13][14][15][16][17][18][19] Lately, an unusually lightly crosslinked variant of NR became known, which forms strain-induced crystals that do not vanish at room temperature. 20 Since a fraction of less than 20% strain-induced crystals retains the NR network in a highly elongated shape and it recovers its original shape not before these crystals are melted, it is referred to as shape memory natural rubber (SMNR).…”