Development and optimization of crystallization-inhibited polymer networks for strain-induced switching from entropy- to energy-elastic behavior

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Crystallizable, amorphously quenched polymer networks, which spontaneously crystallize in a strain-induced manner upon shock loading, possess enormous shock and energy absorption capability. However, since this ability is lost after a short time due to the onset of thermal crystallization, the objective of this project is to develop a novel concept for the synthesis of polymer networks that remain amorphous up to a certain threshold temperature above room temperature and spontaneously crystallize exclusively under mechanical deformation. This is to be achieved by co-crosslinking an amorphous polymer and a polymer capable of crystallization, whereby the polymers used exhibit significant partial miscibility, as is the case, for example, with polymers containing carbonyl groups and polyvinylidene fluoride (PVDF). In the first step, a suitable reaction for the chemical crosslinking is searched, which actually connects both polymers, in order to subsequently study the stable, or metastable miscibility of the polymers and their thermal, or strain-induced crystallization ability as a function of composition and degree of crosslinking. Based on the knowledge gain, the realization of an elastomer stable in the amorphous state, capable of spontaneous strain-induced crystallization, and possessing indefinite shock and energy absorption capability is expected.