Hydrophilic shape memory polymer hydrogels with virous pore structures and shape changing performance

The preparation of a porous shape memory hydrogel with excellent shape changing performance is a hot research topic at present. In this paper, hydrophilic hydrogels were synthesized using polypropylene glycol (PPG) and polyethylene glycol (PEG) as raw materials and hexamethylene diisocyanate (HDI) as crosslinking agent. The pore structures were developed by gas foaming and salt leaching methods. The results showed that the hydrophilicity of hydrogel and the swelling rate in phosphate buffered saline (PBS) increased with the increase of PEG mass fraction, the shape changing performance of hydrogels varied as well with high shape recovery rate ≥90%. The recovery speed in aqueous environment was faster than in the air. After embedding hydroxyapatite (HA) particles, the materials exhibited appropriate degradable properties and good in vitro mineralization performance. Therefore, the obtained PPG/PEG system hydrogels is expected to become an ideal platform for tissue engineering and other applications in the biomedical field.