Miscibility and Properties of New Poly(propylene succinate)/Poly(4-vinylphenol) Blends

Poly(propylene succinate) (PPSu) is a biodegradable polyester with a fast biodegradation rate. New semicrystalline/amorphous blends by mixing PPSu and poly(4-vinylphenol) (PVPh) were prepared by solution casting. A single composition-dependent glass transition temperature was observed over the entire composition range in differential scanning calorimetry (DSC) traces of the quenched blend samples showing miscibility in the amorphous phase. The blends were also found to be miscible in the melt phase, as evidenced by melting point depression. The Flory–Huggins interaction parameter was found to be χ1,2 = −1.21. In Fourier transform infrared spectra, a small shift in the characteristic absorbance peaks for the ester carbonyl and hydroxyl groups of PVPh supported the hypothesis of intermolecular interactions due to hydrogen bonding. The crystallization rates of PPSu in the blends were slower than those of the neat polymer. Wide-angle X-ray diffraction patterns showed that the final degree of crystallinity decreased with increasing PVPh content. Blends with intermediate composition were amorphous. The multiple melting behavior of the blends was studied with standard and step-scan DSC.