Nanocomposites of poly(l-lactide) and surface modified magnesia nanoparticles: Fabrication, mechanical property and biodegradability

A novel nanocomposite based on biodegradable poly(l-lactide) (PLLA) was prepared by the incorporation of surface modified magnesia (g-MgO) nanoparticles using a solution casting method. The mechanical properties, biodegradable properties and protein adhesion behavior of the g-MgO/PLLA nanocomposites were investigated. Scanning electron microscopy (SEM) results showed that g-MgO nanoparticles could comparatively uniformly disperse in PLLA matrix. The addition of g-MgO nanoparticles to PLLA matrix improved the tensile strength and elastic modulus, whereas reduced the elongation at break. The mass loss results showed that the nanocomposites with higher g-MgO content had faster degradation rates. The in vitro pH value determination results indicated that the g-MgO nanoparticles could neutralize effectively the lactic acid resulting from the degradation of PLLA. The g-MgO/PLLA nanocomposites exhibited enhanced protein adsorption, i.e., with the increase of g-MgO content, the amount of protein adsorption increased. The (5 wt%)g-MgO/PLLA nanocomposites adsorbed 33% more protein than the pure PLLA.

Research Highlights
► The MgO nanoparticles are first selected as the added filler to the PLLA biodegradable polymer because they are alkaline oxide which can neutralize the lactic acid coming from the PLLA degradation.
► The ring-opening polymerization of ε-CL is adopted to surface modified MgO nanoparticles. A certain amount modified MgO nanoparticles can disperse uniformly in the PLLA polymer matrix.
► The experimental results showed that the addition of modified MgO nanoparticles improved the mechanical property, degradation rate and the adsorption of protein. These results demonstrated that the g-MgO/PLLA nanocomposites were advantageous for biomedical application.