Combining Low-Emissivity Thin Coating and 3D-Printed Original Designs for Superior Fire-Protective Performance

Area of Science:

• Materials Science
• Polymer Science
• Additive Manufacturing

Background:

• Three-dimensional (3D) printing enables complex object design.
• Previous research created a hydrogel-filled sandwich material with reduced heat release rate (HRR).
• However, the time to ignition (TTI) of this material remained unimproved.

Purpose of the Study:

• To delay the time to ignition (TTI) of a hydrogel sandwich 3D-printed multimaterial.
• To enhance the thermal resistance properties of the 3D-printed material.

Main Methods:

• Incorporation of an agar and vermiculite hydrogel phase into an ethylene vinyl acetate copolymer matrix containing aluminum trihydroxide.
• Deposition of a low-emissivity thin coating using pulsed DC magnetron sputtering on the material's surface.
• Evaluation of thermal resistance performance using mass loss cone calorimetry.

Main Results:

• The hydrogel sandwich material demonstrated significantly reduced peak HRR (86%) and total heat release (64%).
• The TTI was not improved in the initial hydrogel sandwich material.
• The addition of a low-emissivity coating effectively delayed the TTI of the 3D-printed multimaterial.
• The coated material exhibited dramatically enhanced thermal resistance properties.

Conclusions:

• A low-emissivity coating applied via pulsed DC magnetron sputtering is effective in delaying the ignition time of 3D-printed hydrogel sandwich multimaterials.
• This coating functions by reflecting infrared radiation, thereby reducing heat absorption by the underlying material.
• The developed coated material shows significant potential for applications requiring improved thermal resistance and fire safety.