Properties evaluation of eco-friendly chitosan microcapsules fabricated with oxalic acid and sodium phosphate dibasic mixed cross-linker

Crosslinking of chitosan microcapsules is important for control purposes according to their applications and influences their mechanical, thermal, and chemical stability, and tripolyphosphate (TPP) has been predominantly utilized in the electrospray technique for their production. The properties of chitosan microcapsules produced by electrospraying technique and cross-linked with a mixed cross-linking solution (OxPh), consisting of oxalic acid and sodium phosphate dibasic were studied. The formed capsules were characterized by SEM, XRD, FTIR, and the stability and mechanical properties of the capsules were studied. The cross-linked microcapsules provided smooth morphology and exhibited mechanical strength of 80% in the undried state, with dried state mechanical strength of 21.2N as against 19.8N of TPP cross-linked chitosan microcapsules. The microcapsules were also stable in a pH solution of 3.0-5.0.