Facile design of heat-triggered shape memory ethylene-acrylic acid copolymer/chloroprene rubber thermoplastic vulcanizates

Abstract

Stimuli-responsive shape-memory ethylene-acrylic acid copolymer (EAA)/chloroprene rubber (CR) thermoplastic vulcanizates (TPVs) were prepared via dynamic vulcanization. Meanwhile, a simple and effective strategy was designed to achieve rapidly reconfigurable shape fixity and shape recovery for a heat-triggered shape-memory polymer (HSMP), which was derived from a typical sea-island structured EAA/CR TPVs. Field emission scanning electron microscopy (FE-SEM) showed the average diameter of CR particles in EAA/CR TPVs was 3~8 µm. In this work, the mechanical properties results showed that the EAA/CR TPV had high tensile strength, indicating a strong interface interaction between EAA and CR, which would inevitably improve the shape recovery (SR) and shape fixing (SF) ability of TPVs. This HSMP exhibited the surprising shape-memory property (shape fixity ratio ~97%, shape recovery ratio ~95%, and fast recovery speed <30 s). The dynamic mechanical behavior and stress relaxation behavior of EAA/CR TPVs were characterized, and the results demonstrated that the high modulus value supported the improvement of SF ratios, and with the decrease continuously of EAA in the EAA/CR TPVs, the low-stress relaxation ratio stimulated the improvement of SR ratios of the EAA/CR TPVs. This novel HSMP expected to open up a wide range of potential applications in smart devices.

Keywords

• mechanical properties
• chloroprene rubber
• ethylene-acrylic acid copolymer
• shape memory polymers
• thermoplastic vulcanizate