Heat-stimuli controllability of shape memory thermoplastic epoxy filaments by adding polyethylene glycol

Abstract

This study prepared shape-memory thermoplastic epoxy (TEP)-polyethylene glycol (PEG) filaments for the first time, and the heat-stimuli controllability of shape memory function was innovatively endowed by adding PEG in an environmentally friendly way. PEG regulates the glass transition temperature of PEG-modified thermoplastic epoxy (TEP–PEG) without interfering with the polymerization reaction of epoxy. The melt spinning temperature of TEP–PEG is also reduced from 300 °C to 220 °C, and the spinning effect is improved. After PEG modification, Young's modulus of TEP–PEG filaments drawn from TEP–PEG pellets was higher at room temperature. The developed TEP–PEG filaments have excellent shape memory effect with high shape recovery rates of 93.1%–99.0%, and shape fixation rates ranging from 95.8% to 99.1% are also improved after PEG modification. Furthermore, TEP–PEG filaments have controllable stimuli temperatures of shape memory ranging from 69 °C to 105 °C. Additionally, the recovery stress of TEP–PEG filaments after PEG modification was increased to 1.77 MPa, and the recovery temperature of the maximum recovery stress is reduced from 97 °C to 58 °C as PEG content increases to 15 wt%. The problems of difficult melt processing and uncontrollable stimuli temperature for TEP were solved in this study. The developed TEP-PEG filaments with heat-stimuli controllability of the shape memory function demonstrated excellent thermal actuation capabilities and have shown greater application potential in thermal actuation, smart textiles, and artificial muscles.