Fabrication and Characterization of Dense Chitosan/Polyvinyl-Alcohol/Poly-lactic-Acid Blend Membranes

Dense membranes of Chitosan (CS)/Poly(vinyl alcohol) (PVA)/Poly(lactic acid) (PLA) blend were successfully fabricated using casting technique. The mechanical properties, moisture regain and water vapor permeability of polymer blend membranes were estimated by tensile test, moisture regain rate and dish method test respectively. The microstructures, morphology, chemical composition and thermal properties were also characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) respectively. Results indicated that there were interactions and good compatibility among CS, PLA and PVA. And the blend membranes have good breaking elongation and slightly decreased breaking strength, and show best moisture regain at the case of CS60 (the content of CS in the blends is 60 %). They also have excellent porous structure, which is beneficial to their air permeability and may also contribute to cell regeneration. With the adding of PVA content, the melting peaks of blend membranes reduce and gradually close to that of PVA, demonstrating that the regularity of CS molecular chain may be destroyed and hydrogen bonds of macromolecules in polymers were newly formed. As a result, solution blending of the three polymers could complement their disadvantages and significantly improve the membrane performance of a single polymer, thus promote the mechanical and biological properties of blend membrane.