Formation and characterization of superparamagnetic cross-linked high amylose starch

A gelatinized cross-linked high amylose starch matrix with magnetic propert ies was synthesized via in situ formation of iron oxides inside the polymer matrix. Precipitation and multiple oxidation of ferrous ions were performe d. The samples were observed using transmission and scanning electron micro scopy, showing morphological changes in the magnetic and polymer phases. Th e iron content analysis revealed a decay from one oxidation cycle to the ne xt one if no fresh ferrous solutions are added before the multiple oxidatio n. X-ray diffractograms, magnetization curves and Mossbauer spectra were al so recorded for the characterization of the magnetic phase. The products ex hibit superparamagnetic properties due to the presence of ferrimagnetic nan oparticles, although some other iron compounds are also present. (C) 2000 E lsevier Science Ltd. All rights reserved.