Evaluation of compatibility of poly(vinyl chloride) starch acetate blends using simple techniques

Solution blending of poly(vinyl chloride) (PVC) and starch acetate (d.s. 2. 5) synthesized in our laboratory was carried out in 1,4-dioxane. The compat ibility of these blends based on the heat of mixing and the free-energy con cept was examined theoretically. Experimental evidence for the compatibilit y of these blends was derived from viscometric and ultrasonic studies and d ensity measurements. Interaction parameters suggest that polymer-polymer in teraction is greater than polymer-solvent interaction in the blends under s tudy. All the experimental and theoretical evidence show that the blends ar e incompatible at the compositions studied. Morphological studies showed a uniform dispersion of starch acetate in PVC. (C) 1999 John Wiley & Sons, In c.