The characterization of novel biodegradable blends based on polyhydroxybutyrate: The role of water transport

The present paper focuses on the study of novel blends based on poly(3-hydroxybutyrate) (PHB) and polymers with different hydrophilicity, namely low density polyethylene and polyamide (LDPE and PA), respectively. Polymer blends were produced from five ratios of PHB/LDPE in an effort to regulate the resistance to hydrolysis or (bio) degradation through the control of water permeability. The relation between the water transport and morphology (TEM data) shows the impact of polymer component ratio on the water flux regulation in the hydrophobic matrix. To elucidate the role of hydrophilicity of the second component present in the PHB-based blends, we studied the PHB/PA blends where PA is the polyamide resin composed of statistical copolymer of hexamethyleneadipinate and ε-caprolactam in the ratio 1:1. The use of techniques such as DSC and FTIR-imaging (for T-scale) demonstrates the interaction between PHB and PA in the temperature ranges of crystallization and melting. The general approach based on Flory-Huggins equation is presented as the way to choose the pairs of compatible or partly compatible polymers. Blending PHB with PA could be a simple and effective method to design new matrices for drug delivery in medicine, while the same procedure applied for PHB-LDPE system with better resistance against hydrolysis and lower price than the initial PHB, could be used as novel bioerodible packaging materials.