Constructing segregated polystyrene composites for excellent fire resistance and electromagnetic wave shielding

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Polystyrene (PS) composites are explored for electromagnetic interference (EMI) shielding.
• Achieving ideal flame-retardant properties alongside conductivity is crucial for advanced applications.
• Existing materials often face limitations in balancing these properties.

Purpose of the Study:

• To synthesize and characterize novel PS/silicon wrapped ammonium polyphosphate/multi-wall carbon nanotubes (PS/SiAPP/MWCNT) composites.
• To evaluate the flame retardancy and EMI shielding effectiveness of these segregated hybrid materials.
• To investigate the synergistic effects of SiAPP and MWCNT on PS composite performance.

Main Methods:

• Synthesis via ball milling and hot-pressing techniques.
• Characterization of material structure and distribution using microscopy.
• Thermal stability analysis using thermogravimetric analysis (TGA).
• Flame retardancy assessment via cone calorimeter tests.
• Electromagnetic interference shielding effectiveness measurement.

Main Results:

• Successful introduction and uniform distribution of SiAPP and MWCNT onto PS spheres.
• PS/SiAPP/MWCNT composites with 7 wt% MWCNT demonstrated excellent thermal stability.
• Significant reduction in heat release rate (60.5%) and total heat release (33.9%) observed.
• Achieved EMI shielding performance of 11 dB.
• Synergistic effect between MWCNT and SiAPP promoted dense char layer formation, enhancing flame retardancy.

Conclusions:

• The segregated PS/SiAPP/MWCNT hybrid exhibits enhanced flame retardant properties due to synergistic effects.
• Improved EMI shielding effectiveness is attributed to multiple reflection and adsorption mechanisms.
• These composites are promising candidates for EMI shielding materials with excellent fire retardancy in electronic devices.