ONE-STEP QUATERNIZATION CROSSLINKING OF STARCH WITH 3-CHLORO-2-HYDROXYPROPYLAMMONIUM CHLORIDE/EPICHLOROHYDRIN IN THE PRESENCE OF NH4OH/

Quaternization/crosslinking of starch with 3-chloro-2-hydroxypropyltri methyl-ammonium chloride (CHMAC)/epichlorohydrin (E) in the presence o f NH4OH, NaOH and water was studied. The reaction was optimized and th e products analyzed using solid-state NMR, acid-base titration methods and dye-binding tests. The solid-state NMR data in the presence of wa ter confirmed the hydroxypropyl and trimethylammoniumhydroxypropyl gro ups in the obtained ion-exchanger. Although the linkage to starch coul d not be proved, the CH2 groups linked to nitrogen and to oxygen could be tentatively assigned. Optimal molar quantities and ratios are at s tarch: E:NH4OH:NaOH:H2O:CHMAC = 0.01:0.03:0.05:0.1:0.01. The exchange capacities (Q's) determined by potentiometric titration are smaller th an values calculated from elemental analysis. This might be due to lon ger equilibrium times required for the exchange of ions, than those, w hich we could use on the automatic titrator. The dye binding propertie s are pH-dependent for the ion-exchangers containing tertiary amine gr oups next to quaternary ammonium groups and close to pH-independent wh en containing only quaternary ammonium groups (prepared in absence of NH4OH). Copyright (C) 1996 Elsevier Science Ltd.