Co-continuous structure enhanced magnetic responsive shape memory PLLA/TPU blend fabricated by 4D printing
Pei Feng, Rongyang Zhao, Feng Yang, Shuping Peng, Hao Pan, Cijun Shuai
Abstract
Combining poly (L-lactic acid) (PLLA) with thermoplastic polyurethane elastomer (TPU) can integrate the advantages of excellent biocompatibility and intrinsic shape memory ability of PLLA and high elasticity and excellent shape memory properties of TPU in the application of minimally invasive surgery for bone tissue engineering.However, TPU easily forms a sea-islandlike structure in PLLA matrix, decreasing shape memory properties.In this study, a cocontinuous structure of TPU phase in PLLA matrix was constructed by adding Fe 3 O 4 nanoparticles due to the changed interfacial tension and flow behavior of TPU, which endowed the TPU/PLLA/Fe 3 O 4 blend fabricated via selective laser sintering (SLS) with excellent shape memory properties.As a result, the morphology of TPU in the blend changed from sea-islandlike structure to complete co-continuous structure with increasing Fe 3 O 4 content (0 to 10wt%), and shape recovery ratios in 50 C water increased from 66.67 to 95.92%.The introduction of Fe 3 O 4 endowed the blend with magnetic responsive shape memory in alternating magnetic field because Fe 3 O 4 could heat it by generating heat from relative friction and particle collisions.Besides, the tensile modulus and hardness of the specimen with 10wt% Fe 3 O 4 nanoparticles increased.In addition, the blend demonstrated excellent biocompatibility by promoting cell adhesion, spreading, and proliferation.