Rheological properties of pectin, poly(vinyl alcohol) and their blends in aqueous solutions

Abstract

Abstract The new blends composed of natural polysaccharide - pectin and synthetic water soluble polymer - poly(vinyl alcohol) (PVA) are attractive materials due to their biocompatibility, non-toxicity and biodegradability. In this work the rheological properties of aqueous solutions of pectin (PEC), poly(vinyl alcohol) and their mixtures at various weight ratios (70/30, 50/50, 30/70) have been investigated. Flow measurements were carried out using a rotary viscometer with concentric cylinder at different temperatures (20-70 ºC) and shear rates (24- 1234 s-1). The flow parameters and energy of activation have been calculated from the flow curves and Arrhenius plots, respectively. It was found that studied polymer solutions exhibited non-Newtonian behavior, moreover, the flow properties were dependent on the blend composition. The result show that practically there was no thixotropy in studied system but some interactions between PVA and pectin in water occurred.