Miscibility, properties and morphology of biodegradable blends of UHMW-PPC/PVA/EVOH

Thermally stable and biodegradable blends of ultrahigh molecular weight poly(propylene carbonate) (UHMW-PPC), poly(vinyl alcohol) (PVA) and poly(ethylene-co-vinyl alcohol) (EVOH) were melt compounded in a batch mixer followed by compression molding. The miscibility, mechanical properties, thermal behavior, and morphologies of the blends were investigated by torque rheometer, Fourier transform infrared spectroscopy, tensile strength test, thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy. The experimental results showed well interfacial miscibility among phases of PVA, EVOH and PPC. The hydrogen bonding interaction between PPC with PVA and/or EVOH can also be confirmed by Fourier transform infrared spectroscopy spectra. The study on the mechanical properties and thermal behavior demonstrated that PVA/EVOH content can enhance the tensile strength, thermal stability and crystallinity of the blends dramatically. Further, scanning electron microscopic observation revealed a three-phase structure with good interfacial adhesion.