Subject Number             : S-20-NI-0043

Support Type                : Technical support (except the training),

Proposal Title (English)      : Facile Synthesis, Characterization of Various Polymer Immobilized on Ferrite Nanoparticles Applying the Coprecipitation Method

Username (English)         : Junichi Ida

Affiliation (English)             : Soka University, Faculty of Science and Engineering, Department of Science and Engineering for Sustainable Innovation

1. Summary

Magnetite (Fe₃O₄) nanoparticles (MNP) are one of the typical iron oxides and have superparamagnetic property due to its nano size. To date, a variety of synthetic methods of MNP such as co-precipitation, oxidative precipitation, thermal decomposition, hydrothermal synthesis, sol-gel, and micro emulsion method have been reported by many researchers. Of these synthetic methods, the co-precipitation method is the most commonly used process because of its convenience and low cost. In the method, MNP can be synthesized simply by adding a base to an aqueous iron salt solution (Fe²⁺/Fe³⁺ = 1/2) in an inert atmosphere. However, MNP is known to aggregate easily and is also oxidized after synthesis. To avoid the aggregation and the oxidation, coatings of MNP surface with various kinds of polymers such as chitosan, dextran, polyacrylic acid (PAA), polyethylene glycol (PEG) have been examined to improve dispersibility as well as chemical stability.

1. Tural et al. recently reported that when a polymer containing carboxyl groups such as poly (methacrylic acid) was added to the coprecipitation solution during MNP synthesis, the polymer was immobilized on MNP surface immediately after MNP formation. A similar phenomenon has been reported for poly (ethylene glycol) which contains hydroxyl groups and polyaniline which contains amino groups.

However, there is no report on what kind of polymer (or functional group) can be used or how the difference of polymers affect on the synthesis of polymer/MNP composite by using the modified co-precipitation method.

In this study, we examined systematically the effect of different polymer (functional groups, Table1) on the one-step synthesis of polymer immobilized MNP via the modified co-precipitation method. The purposes of this study are to clarify 1) what kind of polymer can be applicable for the synthesis of polymer/MNP via the modified co-precipitation method, and 2) the effect polymer type on the characteristics of the resulting polymer/MNP composites.

2. Experimental

The magnetic performances of the resulting samples were characterized by a vibrating sample magnetometer in the magnetic field up to ±10 kOe. (TOEI INDUSTRY CO., LTD, VSM-5, JAPAN). Total of 24 samples were measured.

3. Results and Discussion

The experimental results showed that for all the samples, the saturation magnetization (Ms), the remnant magnetizations (Mr) and the coercivity(Hc) decreased with the increase of the immobilized polymer amount.

4. Others

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5. Publication/Presentation

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6. Patent

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