Structure and Property Evolution of Microinjection Molded PLA/PCL/Bioactive Glass Composite

In this study, the microinjection molding technology was adopted to prepare polylactic acid (PLA)/polycaprolactone (PCL)/bioactive glass (BG) composites with varying BG contents for biomedical applications. The various measurement techniques, including scanning electronic microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, the water contact angle (WCA) test, the mechanical test, and in vitro biological evaluations, were applied to characterize the above interesting biocomposites. The experimental results show that the extremely strong shear force field generated during the microinjection molding process could induce the in situ formation of micron PCL dispersed phase fibril structures and strongly promote the homogeneous dispersion of micron BG filler particles in the PLA/PCL polymer matrix, which therefore leads to a significant improvement in the specific mechanical property of the PLA/PCL/BG composite. For example, with BG fillers content increasing to 10 wt%, the Young's modulus of the above obtained PLA/PCL/BG composite could reach 2122.9 MPa, which is 1.47 times higher than that of the unfilled PLA/PCL blend material. In addition, it is also found that under the simulated body fluid (SBF) environment, the incorporated BG fillers in the PLA/PCL polymer matrix could be effectively transformed into hydroxyapatite (HA) components on the treated sample surface, thus being greatly advantageous to enhancing the material's in vitro bioactivity. Obviously, the microinjection molded PLA/PCL/BG biocomposites could exhibit excellent comprehensive performance, revealing that the microinjection molding processing method could hold great potential in industrialization applications of the resulting biodegradable biomedical materials.