Fengguang Du

New biodegradable blends from aliphatic polycarbonate and poly(vinyl alcohol)

Poly(propylene carbonate/poly(vinyl alcohol) (PPC/PVA) blends with various PVA contents were prepared by a solution casting technique. The thermal and mechanical properties and the morphologies of the blends were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), static mechanical measurements, scanning electron microscopy (SEM) and FT-IR techniques. The TGA results showed that the introduction of PVA led to a slightly earlier decomposition of the PPC. DSC analysis and SEM observation indicated that the PPC/10% PVA blend was a miscible system, while those containing more than 20% of PVA were two phase systems. FT-IR revealed that the hydroxyl-stretching peak shifted to a higher wave number, and the carbonyl-stretching peak to a lower wave number with increasing PVA content. This indicated a specific interaction between PVA and PPC. Therefore the tensile strength and stiffness of the blends tended to increase greatly with increasing PVA content.