The miscibility of the poly(epsilon-caprolaetone)/poly(vinyl methyl ether). PCL/PVME system. is investigated by differential scanning calorimetry. Thermal analysis results indicate that the system is semicrystalline/amorphous and the PCL degree of crystallinity is influenced significantly by the composition of the mixture as well as by the thermal treatment. The two polymers form blends containing a single amorphous miscible: phase over the entire composition range as evidenced by the constant presence of a single glass transition temperature. T-g. A phase separation process occurs when the blends are heated just above the melting paint of PCL. giving a lower critical solution temperature (LCST) behaviour.