Exceptionally Flame Retardant Sulfur-Based Multilayer Nanocoating for Polyurethane Prepared from Aqueous...

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Current flame retardant (FR) methods for polymers often involve harmful chemicals and degrade material properties.
• There is a need for environmentally benign and effective FR solutions that can be applied as a post-treatment.

Purpose of the Study:

• To develop and evaluate an environmentally friendly nanocoating for flame retardancy on flexible polyurethane foam.
• To investigate the flame retardant mechanism and performance of the nanocoating.

Main Methods:

• Layer-by-layer (LbL) assembly was used to deposit chitosan (CH) and poly(vinyl sulfonic acid sodium salt) (PVS) bilayers onto polyurethane foam.
• Flame testing using a butane torch and cone calorimetry were employed to assess performance.

Main Results:

• The CH-PVS nanocoating (10 bilayers, ~30 nm thick) effectively prevented foam melt dripping and flame propagation.
• The coating resulted in a 52% reduction in peak heat release rate.
• Degradation released non-flammable gases, contributing to flame extinguishment.

Conclusions:

• The water-based, environmentally benign nanocoating offers an effective post-treatment for flame retardancy on various substrates.
• This LbL assembly method provides a promising approach for enhancing the fire safety of flexible materials without compromising their properties.