Multiple/Two‐Way Shape Memory Poly(urethane‐urea‐amide) Elastomers

Abstract

Multiple and two-way reversible shape memory polymers (M/2W-SMPs) are highly promising for many fields due to large deformation, lightweight, strong recovery stress, and fast response rates. Herein, a semi-crystalline block poly(urethane-urea-amide) elastomers (PUUAs) are prepared by the copolymerization of isocyanate-terminated polyurethane (OPU) and amino-terminated oligomeric polyamide-1212 (OPA). PUUAs, composed of OPA as stationary phase and PTMEG as reversible phase, exhibit excellent rigidity, flexibility, and resilience, and cPUUA-C 7 -S 25 exhibits the best tensile property with strength of 10.3 MPa and elongation at break of 360.2%.

Strength Enhancement of Aliphatic Polyurethane Film by Solution Annealing

“…Polyurethane elastomer (PU) has attracted more and more attention due to its excellent optical properties, water resistance, and endurance depending on its microphase separation structure between the soft and hard domain. − Based on this, PU has been widely used in automobile windshields, military engineering, aerospace, and other fields. − Several methods have been reported to enhance the strength and bearing capacity of PU, because of its application need. − Sacrificial bondsare has been introduced to improve the mechanical properties and toughness of PU. − A transparent degradable polyurethane elastomer (PHI) with excellent fracture strength and toughness was successfully prepared, in which energy was dissipated by using imidazolidinyl urea (IU) as a multihydrogen bond motif . The mechanical strength and elasticity of PU crosslined with pseudorotaxane (PS) were significantly improved by the effective cooperation of the ring sliding effect and hydrogen bond stacking network .…”