New Inverse Emulsion-Polymerized Iron/Polyaniline Composites for Permanent, Highly Magnetic Iron Compounds via Calcination

Tar-Hwa Hsieh; Lin-Chia Ho; Yen-Zen Wang; Ko-Shan Ho; Cheng-Hsien Tsai; Li-Fan Hung

doi:10.3390/polym13193240

New Inverse Emulsion-Polymerized Iron/Polyaniline Composites for Permanent, Highly Magnetic Iron Compounds via Calcination

Polymers (Basel). 2021 Sep 24;13(19):3240. doi: 10.3390/polym13193240.

Authors

Tar-Hwa Hsieh¹, Lin-Chia Ho², Yen-Zen Wang³, Ko-Shan Ho¹, Cheng-Hsien Tsai¹, Li-Fan Hung¹

Affiliations

¹ Department of Chemical and Materials Engineering, National Kaohsiung University of Science & Technology, 415 Chien-Kuo Rd., Kaohsiung 80782, Taiwan.
² Tri-Service General Hospital, 325 Sec. 2 Chenggong Rd., Neihu District, Taipei City 11490, Taiwan.
³ Department of Chemical and Materials Engineering, National Yu-Lin University of Science & Technology, 123, Sec. 3, University Rd., Dou-Liu City, Yun-Lin 64301, Taiwan.

Abstract

The hydrophilic initiator potassium persulfate (KPS) was converted into a hydrophobic molecule by complexing with cetyltrimethylammonium bromide (CTAB) at both ends of the molecule (CTAPSu). Inverse emulsion polymerization thus proceeded inside micelles dispersed in the affluent toluene with CTAPSu as the initiator. Polyaniline (PANI) formed inside the micelles and entangled with Fe₃O₄ nanoparticles already esterified with oleic acid (OA). Iron composites consisted of OA-esterified Fe₃O₄ nanoparticles covered with PANI after de-emulsification. After calcination at 950 °C in an argon atmosphere, the resultant iron compound was a mixture of α-Fe (ferrite) and Fe₃C (cementite), as determined by X-ray diffraction. Eventually, the calcined iron compounds (mixtures) demonstrated superparamagnetic properties with a high saturation magnetization (Ms) of 197 emu/g, which decayed to 160 emu/g after exposure to the atmosphere for four months.

Keywords: inverse emulsion polymerization; polyaniline; superparamagnetic.