Preparation and properties of biodegradable blend containing poly (propylene carbonate) and starch acetate with different degrees of substitution

A series of starch acetates (SAs) with different degrees of substitution (DS) were prepared by chemically converting the hydroxyl group of natural cornstarch (NS) into an acetyl group. Biodegradable poly (propylene carbonate) (PPC) was melt blended with these SAs in a Haake mixer. The morphologies, mechanical and thermal properties of PPC/SA and PPC/NS blends were investigated. PPC/SA (DS < 0.88) showed better tensile property and impact strength than those of PPC/NS. Scanning electron microscopy (SEM) and Fourier transform infrared spectra (FTIR) revealed strong interfacial adhesion between the SA fillers and PPC matrix. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated the addition of SA led to improved thermal stability of the blend. Among all the samples prepared, the PPC/SA (DS = 0.51) has the optimal mechanical and thermal properties. The methodology described here represents a promising approach for the production of cost competitive biodegradable polymer blends.