Maize amylose, separated from granular starch by means of an aqueous leaching process, was used to investigate spherulite formation from concentrated mixtures of starch in water. Amylose (10-20%, w/w) was found to form a spherulitic semicrystalline morphology over a wide range of cooling rates (1-250 °C/min), provided it was first heated to > 170 °C. This is explained through the effect of temperature on chain conformation. A maximum quench temperature of approximately 70 °C was required to produce spherulitic morphology. Quench temperatures between 70 and 110 °C produced a gel-like morphology. This is explained on the basis of the relative kinetics of liquid-liquid phase separation vis-à-vis crystallization. The possibility of the presence of a liquid crystalline phase affecting the process of spherulite formation is discussed.
All Science Journal Classification (ASJC) codes
- Polymers and Plastics
- Materials Chemistry