Characterization of poly(vinylpyrrolidone)-konjac glucomannan blend films

Blend films of konjac glucomannan (KGM) and poly(vinylpyrrolidone) (PVP) we re prepared by using a conventional solvent-casting technique and dried at room temperature. The structure and physical properties were studied by inf rared spectroscopy (IR), wide-angle X-ray diffraction (WAXD), thermogravime tric analysis (TGA), differential thermal analysis (DTA), scanning electron microscope (SEM), and by measurement of mechanical properties. The changes of carbonyl stretching bands of KGM and PVP and hydroxyl stretching region of KGM were detected by FTIR analysis. WAXD analysis revealed that the fil m KP-2 got the lowest crystallinity of all the films. The tensile strength and breaking elongation of the blend films reaches the maximum value at 10 wt % PVP content. The DTA curves indicated the existence of interaction bet ween two kinds of macromolecules. Higher thermal stability was attained by konjac glucomannan through blending with PVP. These improvements are attrib utable to the existence of a certain degree of interaction between KGM and PVP molecules resulted from intermolecular hydrogen bonds. Air surface morp hology of the films observed by SEM was consistent with the results mention ed above. (C) 2001 John Wiley & Sons, Inc.