Influence of selective distribution of SiO2 nanoparticles on shape memory behavior of co-continuous PLA/NR/SiO2 TPVs

Abstract

As a kind of commercial thermoplastic elastomers, thermoplastic vulcanizates (TPVs) have been widely used in many fields. In this work, a shape memory polymer (SMP) was fabricated based on co-continuous polylactide (PLA)/natural rubber (NR)/silica (SiO2) TPVs. Selective distribution of SiO2 nanoparticles was achieved with the impact of thermodynamic factor and different processing methods, and the influence on shape memory behavior was investigated as well. The results demonstrated that the co-continuous structure functioned actively in both shape fixity and recovery. The PLA phase played the role of “switch” to control the shape memory behavior, while the deformation of continuous rubber network stored sufficient resilience and successfully drove the shape recovery process. Excellent shape fixing ratio (~100%) and shape recovery ratio (>90%) were obtained when SiO2 nanoparticles were distributed in NR phase. The addition of SiO2 nanoparticles reinforced the rubber phase and the recovery ratio was effectively improved.