Novel sol–gel derived PLA-siloxane-PEO nanocomposite with enhanced thermal properties and hydrolytic stability

This work presents the synthesis, structural investigation, and some properties of a new PLA-Siloxane-PEO hybrid featuring covalent bonds between polymers and siloxane nodes. The synthesis simultaneously connecting PLA and PEO chains directly to the inorganic phase is first achieved through the use of sol–gel process. The structural features, thermal properties and chemical stability of this biocompatible system have been studied by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, 29Si Nuclear Magnetic Resonance (NMR), scanning electron microscopy (MEV), X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). SEM and SAXS measurements showed that the siloxane nodes act as crosslinks between the polymer chains promoting high miscibility between PLA and PEO. FTIR, Raman XRD, DSC, and TGA showed that the presence of the siloxane nodes diminishes the crystallinity of both polymers and increases their thermal resistance. In addition to the absence of brittleness due to the low crystalline character of PLA, this new material exhibits a fantastic resistance to PLA degradation in aqueous medium, attributed both to the presence of the siloxane particles acting as a barrier towards water diffusion and to the hydrophilic PEO segments which may attract water molecules, preventing PLA hydrolysis. All of these characteristics offer an amazing perspective for the use of this hybrid material in biological, medical, and pharmaceutical applications.