PREFERENTIAL INTERCALATION BEHAVIOR OF CLAY AND ITS EFFECT ON THE THERMAL DEGRADATION IN IMMISCIBLE PP/PS BLENDS

The typical immiscible PP/PS blend based clay nanocomposites were prepared via melt blending.The dispersion of clay was determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM).Thermal stability and dynamic mechanical properties were measured by thermogravimetrical analysis (TGA) and dynamic mechanical analysis (DMA),respectively.Preferential intercalation behavior of clay in PP/PS blends was found.The dispersion of clay is significantly influenced by the polarity of PP and PS,meanwhile the location of clay can be controlled by the alternation of the polarity of PP and PS through chemical modification.The clay migrates from PS phase to PP phase with the improvement of the polarity of PP.However,when the PS is sulfonated,clay migrates back to the dispersed PS phase again.The dispersion and location of clay have profound influence on the thermal and dynamic mechanical behavior of PP/PS blends.The better the dispersion of clay in either continuous phase or disperse phase,the higher the thermal stability of the blends.Besides,samples with clay located in the continuous phase can display the best strengthening effect.