Preparation of starch carbamates in homogeneous phase using different mixing conditions

The preparation of starch carbamates of wrinkled pea starch in homogeneous phase catalysed by dibutyltin dilaurate in DMSO as solvent is described. Th e empfloyed isocyanates have linear alkyl chains with 7, 9, 11, 15 or 18 ca rbon atoms. Starch carbamates with equal degrees of substitution and differ ent alkyl chains lengths were synthesised in a reaction flask. The preparat ion of carbamates with equal alkyl chain length and different degrees of su bstitution was also possible. The structures of the polymers were character ised by elemental analysis, IR- and H-1-NMR-spectroscopy. The behaviour of the prepared starch carbamates under thermal loading was investigated by us ing Differential Scanning Calorimetry (DSC) and a hot press. In addition, f or 1-undecyl isocyanate the starch carbamate was prepared both in a kneader and an extruder. The differences in reaction conditions and the results we re discussed.