Fabrication of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/chitosan blend material: synergistic effects on physical, chemical, thermal and biological properties

A new blend material was fabricated from poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] and chitosan through simple solvent casting method. In this investigation, the impact of different contents of chitosan and molar fractions of 4HB monomer towards the hybrid films was determined. The hydrophobic nature of the P(3HB-co-4HB) copolymer was modified by blending with a hydrophilic polymer—chitosan. Thus, the water-absorption capacity and solubility of the blend films were increased proportionally with the increasing content of chitosan. Miscibility of the blend films between the pure components was detected through Fourier transform infrared analysis. The thermal property was altered in terms of melting temperature, whereas the thermal stability of the blend films was greatly increased. Moreover, the scanning electron microscope images indicated that the surface of the blend films was homogenous and porous. Impregnation of chitosan enabled the blend films to exhibit antimicrobial activity against both Gram-negative and Gram-positive bacteria. The blend films with 20 wt% of chitosan were more hydrophilic, porous, biocidal and they have a wider opportunity in various applications such as wound dressing and tissue engineering than the native P(3HB-co-4HB) copolymer.