Polyether polyurethanes: Synthesis, characterization, and thermoresponsive shape memory properties

Abstract

Thermoresponsive shape memory polymers based on polyurethane with soft segment consisting of poly (tetramethylene oxide) (PTMO) and hard segment arising from urethane reaction of tolylene diisocyanate with OH terminal of PTMO and 1,4 butane diol (BD) were synthesized by a two-step process. The molar ratios of the reactants were varied to get polymers of different softhard segment contents. These were characterized by DSC, IR, DMTA, XRD, SEM analyses, and mechanical properties. The shape memory behavior was evaluated by cyclic tensile tests. PTMO served as the switching segments whose crystalline melting was responsible for the switching behavior. As the hard segment-content increased, transition temperature (T trans ) diminished and so did the elongation and tensile strength of the polyurethane. Higher glassy/rubbery modulus ratio observed for higher hard segment-content polymer was conducive to better shape recovery properties. The influence of hard/soft segments on the thermal, mechanical, damping and shape memory properties of the copolymers are presented and correlated to their phase morphology, as investigated by FTIR and SEM.

Effect of phenol end functional switching segments on the shape memory properties of epoxy‐cyanate ester system

“…At T trans + 20°C the shape recovery of low SS content system increases in the order PPPG‐20 < PPCL‐20 < PPTMO‐20. This observation conforms to the trend in modulus ratio ( E g / E r ), which increases in the same manner as has been observed in previous studies also . At high E g / E r ratio, the shape recovery is maximum at minimal recovery time.…”

Thermoresponsive shape memory characteristics of polyurethane electrospun web

“…In association with the change of the NH group absorption peaks, the degree of phase separation (DPS) of the segmented PU can be calculated. [21][22][23] In addition, the hydrogen bonding index R can be obtained from a baseline approach method:…”

Mechanical Behavior of Shape Memory Polymers by 1WE Method: Application to Tecoflex®

“…And since R evolves with e irr (Equation (1)), it also saturates out after a certain amount of cycles. Further optical study and IR study could be done to see the elaborate effect of cycling and programming of Tecoflex Õ [14][15][16].…”