PHYSICAL-PROPERTIES OF POLYMER BLENDS AND THEIR THEORETICAL CONSIDERATION

The physical properties of polymer blends and their theoretical consid eration based on the double-lattice model (DLM) and a simple rheologic al equation of state were investigated. Cloud points of poly(epsilon-c aprolactone) (PCL)/polystyrene (PS) blends were determined using the t hermooptical analysis (t.o.a.) technique. PCL (M-W = 125 000)/PS(M-W = 6200) blends exhibit an upper critical solution temperature (UCST). T he adjustable parameter values are r(2) = 844.859, epsilon/k = -313.09 2 K, and delta epsilon/k = 1381.824 K. For PCL (M-W = 15 000)/PS (M-W = 840) blends, r(2) = 177.560, epsilon/k = -254.163 K, and delta epsil on/k = 1195.827 K. The DLM successfully describes and predicts the pha se behaviour of polymer blends. Steady-state shear viscosity of PCL/li near low-density polyethylene (LLDPE) blends was also investigated. D. s.c. results showed that there is no miscibility between PCL and LLDPE . A simple rheological equation of state successfully describes and pr edicts the flow behaviour of the proposed polymer blend. (C) 1997 Else vier Science Ltd.