Lightly cross-linked natural rubber latex is strain-induced crystallized (SIC) by stretching to a high extension of 1000 %. On removal of the stretching force the crystals avoid the retraction of the NR network and a large elongation of about 900 % is retained at room temperature as long as the elongation-stabilizing crystals are not molten. The recovery of the permanent shape can be triggered conventionally by raising the temperature above the switching temperature but also through mechanical stress applied transverse to the prior elongation direction of the network. For this purpose, athermal melting of the elongation-stabilizing crystals is investigated by determination of the melting temperature (equals switching temperature) Ttrans(st) in dependence on mechanical stress st transverse to the prior strain direction. It is shown that transversal stress suppresses the switching temperature linearly below ambient temperature, followed by melting of the crystals and retraction of the NR network. This effect is called �stress-induced melting�.

Mechanically triggered shape memory polymer

243rd National Meeting (2012)

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