Preparation, properties, and antibacterial application of dialdehyde carboxymethyl cross-linked sesbania gum

Abstract

Suitably modified sesbania gum as a biodegradable functional biomaterials was very attractive in many applications. Therefore, a combination of cross-linking, carboxymethylation, and oxidation was chosen to modify sesbania gum (SG) to expand its use. The experimental results indicated that cross-linking could be completed not only on SG particles, but also between different SG particles. The cross-linking decreased the number of surface hydroxyl groups on SG. The sedimentation volume decreased with the increase of phosphorus content of cross-linked sesbania gum (CLSG). The structure of SG particles was severely disrupted by carboxymethylation and oxidation, while the structure was less affected by cross-linking. The viscosities of SG and modified SG paste in acidic medium were less than those in neutral medium, while their viscosities in alkaline medium were more than those in neutral medium. Cross-linking, carboxymethylation, and oxidation could ameliorate the retrogradation of SG, but decrease its swelling power, freeze–thaw stability, acid, and alkaline resistance. The aldehyde groups had good antibacterial activity against Trichoderma harzianum, whereas the carboxymethyl groups and phosphate ester groups showed poor antimicrobial activity against T. harzianum.