Improvement of biocompatibility of high molecular weight poly-3-hydroxybutyrate by blending with its functionalized oligomers

Oligomers of poly-3-hydroxybutyrate (PHB) were prepared by aminolysis of high molecular weight PHB with ethylenediamine and 1,4-diaminobutane. Polymer-oligomer blends (10, 30, and 50% content of the oligomers) were prepared as films by solution casting. As the content of oligomers increased, a gradual increase in the hydrophilicity of the polymer surface was observed, resulting reflected in the water contact angle decrease from 84° to 72–76°. In addition, a moderate decrease in elongation at break, Young's modulus, and tensile strength for the blends were observed as more oligomer was added to the film. Finally, the viability of NIH-3T3 mouse fibroblasts was higher compared to intact PHB when growing in non-prepared polymer/oligomer mixtures. These findings confirm the benefits of the introduction of a hydrophilic functionalized oligomer into the PHB matrix in terms of improving the biocompatibility of the resulting polymer/oligomer blends.