Improvement of the Miscibility by Combination of Poly(3-hydroxy butyrate) PHB and Poly(propylene carbonate) PPC with Additives

Abstract

A series of blends of biodegradable PHB and PPC with and without additives were prepared in different ratios by the casting method. The effect of additives on miscibility, morphology and melting of PHB and PPC blends was investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), Fourier transform infrared and wide angle X-ray diffraction (WAXD). The immiscibility between the PHB and PPC blends has been shown using DSC and POM. Acetyl triethyl citrate/polyvinyl acetate (PVAc) as plasticizer and compatibilizer was used to improve the miscibility between the PHB and PPC blends. FT-IR confirmed that the miscibility can be improved by additives, therefore the crystallinity and melting temperature of PHB is depression with increasing PVAc content, the OH group broadened and the ester band C=O shifted in blends 7, 8 and 9, due to hydrogen-bonding interaction. The peak position of C=O of blend 1, 2 and 3 remains constant without any change, i.e. PHB and PPC do not form any intact due to their incompatibility. WAXD showed reduced crystallinity and peak broadening in the patterns of the blends. Electrospun fiber of blend 9 has been manufactured and the morphology was investigated by scanning electron microscopy. Electrospun fibers are homogenous and their diameters were affected by solution concentration. It was found that the elongation at the break of electrospun fibers of PHB/PPC blends increased by adding additives.