Formation and characterization of superparamagnetic cross-linked high amylose starch

A gelatinized cross-linked high amylose starch matrix with magnetic properties was synthesized via in situ formation of iron oxides inside the polymer matrix. Precipitation and multiple oxidation of ferrous ions were performed. The samples were observed using transmission and scanning electron microscopy, showing morphological changes in the magnetic and polymer phases. The iron content analysis revealed a decay from one oxidation cycle to the next one if no fresh ferrous solutions are added before the multiple oxidation. X-ray diffractograms, magnetization curves and M?ssbauer spectra were also recorded for the characterization of the magnetic phase. The products exhibit superparamagnetic properties due to the presence of ferrimagnetic nanoparticles, although some other iron compounds are also present.