Experimental Research on Viscoelastic Characteristics of Shape Memory Polymers

摘要

As a class of semi-crystallized polymers, shape memory polymers (SMPs) exhibit significant viscoelastic characteristics in the vicinity of the glass transition temperature T_g, which should affect their shape storage and recovery functionality. However, until now isothermal and elastic assumptions are commonly considered when studying the thermomechanical properties of this class of functionalized materials. This papers aims to present some experimental results about the viscoelastic characteristics of SMPs. Systematic thermomechanical experiments were performed on shape-memory polyurethane under uniaxial tensile loading, which includes the frozen/recovery tests under different constraint conditions, stress-strain cycles and stress relaxation at different temperatures. Based on the testing results, the viscoelastic characteristics effect on the shape frozen and recovery responses of SMPs are discussed, which is of importance in proposing suitable thermo-viscoelastic constitutions about this type of functional materials.