NOVEL HIGH-PERFORMANCE MATERIALS FROM STARCH - 1 - FACTORS INFLUENCING THE LYOTROPIC LIQUID CRYSTALLINITY OF SOME STARCH ETHERS

Starch ethers having side chains of various lengths, controlled and un iform degrees of substitution, and various amylose/amylopectin ratios were obtained by a one-step chemical modification of starch. Factors i nfluencing the phase behavior of these starch ethers were carefully ex amined, and the ones having short side chains were found to exhibit ly otropic liquid crystallinity over wide ranges in degree of substitutio n and amylose/amylopectin ratio. The starch ethers having longer side chains failed to exhibit phase separation due to insufficient degrees of substitution. They generally possessed enhanced hydrophobicity rela tive to starch yet still had controllable numbers of free hydroxyl gro ups. The liquid crystallinity thus produced makes them ideal candidate s for a novel processing technique designed specifically for permanent ly orienting main-chain, lyotropic, liquid-crystalline polymers.