High modulus ratio shape-memory polymers achieved by combining hydrogen bonding with controlled crosslinking
(1241–1245) Journal of Polymer Science B: Polymer Physics 49, #17 (2011)
Pan et al of the Chinese Academy of Sciences, China, synthesized  poly(methyl acrylate)-co-(acrylic acid) (PMA-AA) networks by combining hydrogen bonding with controlled crosslinking that showed full and rapid shape-memory recovery.  High modulus ratios were achieved for the series of PMA-AA networks based on intense self-complementary hydrogen bonding in poly(acrylic acid) (PAA) segments.  This lead to excellent shape-memory effects with strain-recovery ratio above 99%. Meanwhile, faster recovery speed was achieved by the synergistic effect of hydrogen bonding and controlled crosslinking compared to the linear PMA-AA copolymers.  (RDC 7/27/2011)

Relaxation based modeling of tunable shape recovery kinetics observed under isothermal conditions for amorphous shape-memory polymers  
(6212-6218) Polymer 51 #26 (2010)
Heuchel et al of the Institute of Polymer Research, Germany are looking for shape memory polymers, which allow the adjustment of shape-memory properties by variation of physical parameters during programming.  The stress relaxation behaviour of polyurethane (PEU) based shape-memory polymers at temperatures from 0 °C to 80 °C and different strain values from 100% to 250% could be well described by a modified Maxwell–Weichert model of two Maxwell units and a spring. The stress relaxation results in a combination of a slow and a fast decaying process.  (RDC 1/27/2011)