EFFECT OF PROCESSING CONDITIONS ON THE DYNAMIC-MECHANICAL PROPERTIES OF STARCH AND ANHYDRIDE FUNCTIONAL POLYMER BLENDS

Reactive blending of starch with ethylene-propylene-g-maleic anhydride (EPMA) and styrene maleic anhydride (SMA) copolymers was carried out in a batch mixer. The effect of processing conditions, such as mixer s peed and mixing time, on the dynamic mechanical properties and morphol ogy, was studied. Starch/EPMA blends showed two distinct glass transit ions in the G' and G'' plots, one corresponding to the starch and the other corresponding to EPMA. Starch/SMA blends exhibited one broad tra nsition, since the glass transition temperatures of starch and SMA wer e in close proximity to one another. The starch in the blend was sensi tive to the processing conditions used in this study. Increasing the m ixing time from 10 to 20 min and increasing mixing speed from 50 to 10 0 rev min(-1) resulted in increased melting of starch granules. Increa sing the mixing speed and mixing time also resulted in increased degra dation of starch, as evident from the gel permeation chromatography.