Crosslinking of alginic acid/chitosan matrices using bis phenol-F-diglycidyl ether: mechanical, thermal and water absorption investigation

In this study, blends of alginic acid (AA) and chitosan (Cs) cross-linked with bis phenol-F-diglycidyl ether (BPFDGE) were prepared by solvent evaporation method. Chemical structure was analyzed by FTIR showing the existence of interaction between chitosan and sodium alginate. Three transition temperatures were observed for the AA/Cs/BPFDGE blend system in differential thermo-gravimetric analysis thermograms. The first transition showed weight loss due to elimination of absorbed moisture and second transition was due to cleavage of glycosidic linkage of chitosan and decarboxylation from polysaccharide backbone of alginic acid. In the third transition, decomposition temperature of blends (769 °C) was higher as compared to chitosan (580 °C) and alginic acid (620 °C). Investigation on mechanical properties of blends revealed a decreasing trend due to alginate addition that alters crystallization as well as molecular orientation in AA/Cs blend. Increased water uptake was observed owing to interaction between cationic (chitosan) and anionic (alginic acid) groups.