THERMOMECHANICAL PROPERTIES OF BLENDS OF PECTIN AND POLY(VINYL ALCOHOL)

摘要

Blends of citrus pectin and several types of poly(vinyl alcohol) were investigated to determine the effects of compositional variables and polymer type on Aim properties. Some films were also plasticized with glycerol. Films were cast from water onto Lexan(TM) plates, dried, and removed. Thermomechanical properties were obtained using a dynamic mechanical analyzer, and thermodynamic transitions were also obtained using a differential scanning calorimeter. Increasing the amount of poly(vinyl alcohol) in the blends reduced the storage and loss modulus of the films above the glass transition temperature (T-g). The T-g values observed decreased as the amount of PVOH in the blend increased. Addition of glycerol depressed the PVOH T-g and merged it into the T-g of the pectin/glycerol blend. Changes in the molecular weight and degree of ester hydrolysis of poly(vinyl alcohol) exerted a rather small effect on the blends. (C) 1996 John Wiley & Sons, Inc.(dagger) [References: 16]