Curing epoxy with polyvinylpyrrolidone (PVP) surface-functionalized ZnxFe3-xO4 magnetic nanoparticles

• Published in: Progress in organic coatings 2019-11, Vol.136, p.1, Article 105227
• Main Authors: Jouyandeh, Maryam, Ganjali, Mohammad Reza, Ali, Jagar A., Aghazadeh, Mustafa, Paran, Seyed Mohammad Reza, Naderi, Ghasem, Saeb, Mohammad Reza, Thomas, Sabu
• Format: Article
• Language: English
• Subjects: Cure Index; Curing; Dipole interactions; Emission analysis; Epoxy; Ethylene oxide; Fourier transforms; Iron oxides; Lewis acid; Magnetic measurement; Nanocomposites; Nanoparticles; Polyvinylpyrrolidone; Rings (mathematics); Superparamagnetic iron oxide; Zinc; Zn doping
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2019.105227

•Modiffied the bulk and surface compsoition of superparamagnetic iron oxide (SPIOs).•Synthersized and characterized SPIOs, PVP-SPIOs, and Zn-doped PVP-SPIOs.•Nonisothermal DSC used to study effects of surface and bulk modification.•Cure Index suggested Poor cure for epoxy/PVP-SPIOs, Good cure for epoxy/ Zn-doped PVP-SPIOs. Curing reaction of epoxy nanocomposites depends to a large extent on the microstructure and the functionality of nanoparticles. In this work, cathodic electrochemical deposition was practised in synthesis of bare superparamagnetic iron oxide (SPIOs), polyvinylpyrrolidone (PVP) coated SPIOs (PVP-SPIOs), and zinc (Zn) doped PVP-SPIOs (Zn-doped PVP-SPIOs). The resulting SPIOs were fully characterized with X-Ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM), and vibrating sample magnetometry (VSM) analyses. The results demonstrated formation of highly-curable epoxy nanocomposite by gradual replacement of some iron atoms in the bulk structure of PVP-SPIOs with Zn2+cations (Zn-doped PVP-SPIOs). Analyses also approved successful surface functionalization of PVP-SPIOs nanoparticles according to calculations based on the Cure Index (CI) that quantified cure quality of epoxy in the presence of PVP-SPIOs and Zn-doped PVP-SPIOs. Epoxy/PVP-SPIOs curing under nonisothermal DSC enlarged curing window thanks to dipole–dipole interactions between amid group of PVP and the oxirane rings of epoxy. The cure of epoxy changed from Poor to Good state at high (CI changed from 1.42 to 1.60) and low (CI changed from 1.67 to 1.81) heating rates by changing the bulk of PVP-SPIO via Zn doping. Catalyzing effect of Zn2+ through Lewis acid action was the reason for such phenomenon.