Development of thermoplastic epoxy filaments with shape memory properties

Abstract

In this paper, an epoxy resin mixture composed of epoxy and phenol monomers is used to prepare thermoplastic epoxy polymer (EP-TP) through a polymerization reaction and shape memory thermoplastic epoxy filament (SMEF-TP) was successfully developed for the first time through a melt-drawing process. Tensile tests showed that the yield stress of the developed SMEF-TP reached 63 MPa, which is an increase of 54% compared with EP-TP films. Shape memory experiments showed that the developed SMEF-TP has excellent shape memory performance, with a shape fixation rate of 97%, a shape recovery rate of over 97%, and good stability in cycling. Based on the shape memory performance analysis, the shape recovery stress of the SMEF-TP was characterized. Shape recovery stress responded to temperature stability and increased with the increase of strain, reaching 1.45 MPa at a strain of 35%. The SMEF-TP can reach an energy density of 0.066 J/cm3 during thermal actuation and shows greater application potential when processed into textiles. In addition, the chemical structure, thermal performance, and dynamic mechanical performance of SMEF-TPs are analyzed. The developed SMEF-TP shows excellent shape memory performance, and the output shape recovery stress is more than 5 times that of EP-TP film, which provides huge application potential in the fields of artificial muscles and smart textiles.