Characterization of Poly(benzaldehyde-co-thiophene) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Blend: Structural, Thermal, and Morphological Properties

This study investigated the properties of a blend made from two copolymers: poly(benzaldehyde-co-thiophene) (PBT) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). PBT was first synthesized via oxidative coupling of thiophene and benzaldehyde monomers. The synthesized PBT was then mixed with commercially available PHBV in a 50/50 ratio using solution casting. The X-ray diffraction revealed the amorphous nature of PBT and the semi-crystalline nature of PHBV. The Infrared spectroscopy confirmed the presence of both materials in the blend. UV–Vis analysis showed characteristic absorption peaks for both polymers: PBT displayed π–π* transitions and a π–π* transition related to its semiconducting properties, while PHBV exhibited peaks associated with the carbonyl group. The thermogravimetric analysis demonstrated the thermal stability of PBT compared to the degradability of PHBV. The differential scanning calorimetry revealed a decrease in the blend’s melting temperature and enthalpy of fusion compared to pure PHBV, indicating hindered crystallization in the blend. The scanning electron microscopy visualized the distinct morphologies of the two copolymers within the blend, suggesting their immiscibility.