Thermomechanical properties of blends of pectin and poly(vinyl alcohol)

✍ Scribed by David R. Coffin; Marshall L. Fishman; Trung V. Ly

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 688 KB
• Volume: 61
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19960705)61:1<71::aid-app8>3.0.co;2-r

✦ Synopsis

Blends of citrus pectin and several types of poly(viny1 alcohol) were investigated to determine the effects of compositional variables and polymer type on film properties. Some films were also plasticized with glycerol. Films were cast from water onto LexanO 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(viny1 alcohol) in the blends reduced the storage and loss modulus of the films above the glass transition temperature (T,). The Tg values observed decreased as the amount of PVOH in the blend increased. Addition of glycerol depressed the PVOH T, and merged it into the T, of the pectin/glycerol blend. Changes in the molecular weight and degree of ester hydrolysis of poly(viny1 alcohol) exerted a rather small effect on the blends. 0 1996