A Polycarbonate/Magnesium Oxide Nanocomposite with High Flame Retardancy

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanocomposites

Background:

• Polycarbonate (PC) is a widely used engineering thermoplastic.
• Enhancing the flame retardancy of PC is crucial for many applications.
• Magnesium oxide (MgO) is explored as a potential flame retardant additive.

Purpose of the Study:

• To develop a flame retardant polycarbonate/magnesium oxide (PC/MgO) nanocomposite.
• To investigate the effect of MgO on flame retardancy, thermal properties, and degradation kinetics.
• To understand the mechanism of flame retardancy imparted by MgO.

Main Methods:

• Melt compounding was used to prepare the PC/MgO nanocomposite.
• Limited oxygen index (LOI) tests were performed to evaluate flame retardancy.
• Thermogravimetric analysis (TGA) was employed to study thermal properties and degradation.
• Flynn-Wall-Ozawa method was used to estimate apparent activation energy.

Main Results:

• A small addition of 2 wt% MgO significantly increased the LOI to 36.8.
• The onset and maximum degradation temperatures decreased in both air and nitrogen atmospheres.
• Three distinct steps were observed in the thermal degradation kinetics after MgO incorporation.
• MgO increased activation energies in most stages, except the initial one.

Conclusions:

• MgO effectively enhances the flame retardancy of polycarbonate.
• MgO influences thermal degradation by catalyzing degradation and forming a protective barrier.
• The addition of MgO modifies the thermal stability and degradation kinetics of PC.