Time dependent recovery of shape memory polymers

Abstract

Shape memory polymers (SMPs) are polymers that can recover the permanent shape from a temporary shape by external stimuli. In SMP applications, one of the major design considerations is the time necessary to recover the shape without external constraints, or free recovery rate. This paper investigates the free recovery behaviors of an epoxy-based SMP under shape memory (SM) cycles. We found that reshaping the sample at a low temperature and recovering from the deformation at a high temperature yields the fastest recovery rate whilst reshaping at a high temperature and recovering at a low temperature cannot recover the original shape within this work's experimental time frame. The possible mechanism for these observations is discussed. ©2010 Society for Experimental Mechanics Inc.