Creep and Stress Relaxation of Polyurethane-Shape Memory Polymer Foam.

Shape xity and shape recovery of polyurethane shape-memory polymer foams

The thermomechanical properties of polyurethane shape memory polymer (SMP) foams were investigated experimentally. The results obtained can be summarized as follows. (1) By cooling the foam after compressive deformation at high temperature, stress decreases and the deformed shape is Ž xed. Stress decreases markedly in the region of temperature below the glass transition temperature Tg during th...

Shape recovery and irrecoverable strain control in polyurethane shape-memory polymer.

In shape-memory polymers, large strain can be fixed at a low temperature and thereafter recovered at a high temperature. If the shape-memory polymer is held at a high temperature for a long time, the irrecoverable strain can attain a new intermediate shape between the shape under the maximum stress and the primary shape. Irrecoverable strain control can be applied to the fabrication of a shape-...

Transformation-Induced Creep and Creep Recovery of Shape Memory Alloy

If the shape memory alloy is subjected to the subloop loading under the stress-controlled condition, creep and creep recovery can appear based on the martensitic transformation. In the design of shape memory alloy elements, these deformation properties are important since the deflection of shape memory alloy elements can change under constant stress. The conditions for the progress of the marte...

Creep and stress relaxation in a longitudinal polymer liquid crystal: Prediction of the temperature shift factor

The polymer liquid crystal PLC is the PET/0.6PHB copolymer; PET5poly~ethylene terephthalate!, PHB5r-hydroxybenzoic acid ~LC!: 0.65the mole fraction of PHB. This is a multiphase system with PHB-rich islands in a PET-rich matrix. Tensile creep compliance was measured isothermally from 20 °C to 160 °C in 10 °C intervals. Master curves were determined using the time–temperature superposition for 20...

Creep and Stress Relaxation Behavior of Polypropylene, Metallocene-Prepared Polyethylene and their Blends