Thermal Analysis of Crosslinking Reactions in Epoxy Nanocomposites Containing Polyvinyl Chloride (PVC)-Functionalized Nickel-Doped Nano-Fe₃O₄

Abstract

This work reports on the thermal analysis of epoxy containing polyvinyl chloride (PVC) surface-functionalized magnetic nanoparticles (PVC–S/MNP) and its bulk-modified nickel-doped counterpart (PVC–S/MNP/Bi–B). Nanoparticles were synthesized through the cathodic electro-deposition method. The morphology of particles was imaged on a field-emission scanning electron microscope (FE-SEM), while X-ray diffraction analysis and Fourier-transform infrared spectroscopy (FTIR) were used to detect changes in the structure of nanoparticles. The magnetic behavior of particles was also studied by vibrating sample magnetometry (VSM). In particular, we focused on the effect of the bulk (Ni-doping) and surface (PVC-capping) modifications of MNPs on the thermal crosslinking of epoxy using nonisothermal differential scanning calorimetry (DSC) varying the heating rate. The cure labels of the prepared nanocomposites were assigned to them, as quantified by the cure index. The good cure state was assigned to the system containing PVC–S/MNP/Bi–B as a result of excessive ring opening of epoxy. Cure kinetics parameters of PVC–S/MNP/Bi–B incorporated epoxy was obtained by the use of isoconversional methodology. The activation energy of epoxy was decreased upon addition of 0.1 wt% of PVC–S/MNP/Bi–B due to the reaction of Cl− of PVC by the functional groups of resin.

Keywords

• crosslinking
• surface functionalization
• cure index
• epoxy
• cure kinetics