Preparation and Mechanical Properties of Modified Epoxy Composites Through Plasma Fluorination of Filler

Plasma fluorination of fillers can improve the electrical properties of epoxy resin composites, while there is hardly any research on its influence on other properties of the materials. In this study, nano-sized titanium dioxide particles were modified by dielectric barrier discharge (DBD) plasma. In order to evaluate the effect of fluorination, fillers before and after treatment, according to different mass fractions of 0.1%, 0.5%, 1% and 5%, respectively, were added into epoxy resin to prepare composites. The tensile properties, bending behavior and glass transition temperature (Tg) of the composites were studied. The results show that after fluorination, the tensile properties of the material have been improved basically, with tensile strength ($\sigma_{M}$) increased by up to 17% and tensile strain at break ($\varepsilon_{B}$) by up to 27%. In terms of bending performance, when the filler content was constant, flexural strength ($\sigma_{fM}$) and flexural stress at break ($\sigma_{fB}$) of the composites prepared with fluorinated filler increased and flexural stress at conventional deflection ($\sigma_{fc}$) and flexural modulus (Ef) can increase by up to 25%. Differential scanning calorimetry (DSC) analysis shows that Tg will not decrease due to fluorination treatment. The molecular dynamics simulation results were in good agreement with the experimental results.