Shape‐Memory Performance of Thermoplastic Amphiphilic Triblock Copolymer Poly(d,l‐lactic acid‐co‐ethylene glycol‐co‐d,l‐lactic acid) (PELA)/Hydroxyapatite Composites

Abstract

Biodegradable polymer/hydroxyapatite (HA) composites are desired for skeletal tissue engin­eering. When engineered with thermally responsive shape‐memory properties, they may be delivered in a minimally invasive temporary shape and subsequently triggered to conform to a tissue defect. Here, the shape‐memory properties of thermoplastic amphiphilic poly( d,l ‐lactic acid‐ co ‐ethylene glycol‐ co ‐ d,l ‐lactic acid) (PELA) ( M w = 120 kDa) and HA‐PELA composites are reported. These materials can be cold‐deformed and stably fixed into temporary shapes at room temperature and undergo rapid shape recovery (<3 s) at 50 °C. Stable fixation (>99% fixing ratio) of large deformations is achieved at −20 °C. While the shape recovery from tensile deformations slows with higher HA contents, all the composites (up to 20 wt% HA) achieve high shape recovery (>90%) upon equilibration for 10 min at 50 °C. The permanent shapes of HA‐PELA can be reprogrammed at 50 °C, and macroporous shape‐memory scaffolds can be fabricated by rapid prototyping. image