The Porous Structure and Mechanical Properties of Injection Molded HA/PA66 Scaffolds

Abstract

Abstract Hydroxyapatite/polyamide-66 (HA/PA66) composite scaffolds were prepared using injection-molding technique, and also analyzed by means of scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), Fourier transform infrared spectroscopy (FTIR) and mechanical testing. Compared with common methods including solvent casting/particulate leaching, phase separation and so forth to fabricate scaffolds, this process is of a rapid and convenient manner. The increase of HA content can increase the stiffness of composite scaffolds accompanied by the reduction of impact strength, pore size and porosity. The storage modulus of composite scaffolds increases with increasing HA content and with decreasing porosity. The damping (tan δ) of PA66 decreases with the increase of HA content, and the α and β relaxation peaks of PA66 for the foamed HA/PA66 composites slightly shift to lower value, indicating that both HA and gas in the foamed HA/PA66 composites have an effect on the chain mobility of the polymer and the interaction between the polymer chains. The microstructure of the 30 wt% and 40 wt% HA/PA66 composite scaffolds with porosity more than 59 % and pore size ranging from 100 to 500 μm is similar to that of dry human trabecular bone. The obtained composite scaffolds with 30 wt% and 40 wt% HA have a compressive modulus of 232 to 443 MPa, and a compressive strength of 9.3 to 9.8 MPa, similar to or a little higher than those of trabecular bone, and close to those of the cancellous bone.