STARCH CITRATE - PREPARATION AND ION-EXCHANGE PROPERTIES

Starch was allowed to react thermochemically (oven versus drum drying- oven) with citric acid to potentially yield biodegradable products pos sessing high ion exchange capacity. Reaction variables studied were: s tarch type (amylose content 0-70%), pH (0.5-8.5), sodium level (0-3 mo les), citric acid level (0.1-0.5 moles), reaction time, temperature (1 10-140 degrees C) and sodium dihydrogen phosphate catalysis. Reaction efficiencies approaching 100% were achieved, while minimizing crosslin king and maximizing carboxyl content. Carboxyl content was determined and copper binding capacity at pH 4.5 was evaluated.