Shape‐Memory Natural Rubber: An Exceptional Material for Strain and Energy Storage

Abstract

Shape‐memory polymers (SMPs) are smart, responsive materials with numerous potential applications. Based on previously introduced shape‐memory natural rubber (SMNR), which shows exceptional properties such as strain storage of 1000%, cold storage, cold programmability, and mechanical and thermal triggers tunable both during and after programming, different SMNRs regarding their shape‐memory parameters are investigated. Furthermore, their energy‐storage capability and their mechanical properties are explored. SMNRs show fixity ratios of up to 94% and excellent recovery ratios of up to 100% whereas strains even above 1000% can be stored. Energies of up to 4.88 J g−1 can be stored with efficiencies of up to 53.30%. Further, the Young's modulus of SMNR can be switched by two orders of magnitude upon triggering or programming.

Environmental Memory of Polymer Networks under Stress

“…[ 10 ] The set of properties can be greatly enhanced by blending, [11][12][13][14][15] functional groups, [16][17][18] and additives. [ 20,21 ] It was found that whenever NR is vulcanized below a critical degree of crosslinking, it generates crystals upon strain that are stable at room temperature and can thus stabilize a programmed shape. One way to achieve this is to design a material that allows re-arrangement of its microstructure by such an external stimulus, which then stays intact after removing the stimulus.…”

Programmable Macroporous Photonic Crystals Enabled by Swelling‐Induced All‐Room‐Temperature Shape Memory Effects

“…After cooling below T trans , the fixed temporary shape can be stored under ambient conditions for a long period of time. [47][48][49][50][51][52] The convenient preparation of temporary shape is usually achieved by directly stretching or compressing the SMPs under ambient conditions through "reversible plasticity shape memory" or strain-induced polymer crystallization. [19] Thermoresponsive SMPs have recently been utilized in fabricating smart, programmable nanooptical components, such as diffraction gratings and optical beam-power splitters.…”

Biobased Heat-Triggered Shape-Memory Polymers Based on Polylactide/Epoxidized Natural Rubber Blend System Fabricated via Peroxide-Induced Dynamic Vulcanization: Co-continuous Phase Structure, Shape Memory Behavior, and Interfacial Compatibilization

“…Tiller and co-workers [18][19][20] described strain-induced crystals in a lightly cross-linked NR served as a temporary network to fix the deformed shape, fulfilling the shape memory performance. The trigger temperature for shape recovery can be increased to room temperature by changing the crosslink density, deformation temperature, and the stressed state of the deformed sample.…”