Bio-Based Rigid Polyurethane Foams Modified with Phosphorus Flame Retardants

Area of Science:

• Materials Science
• Polymer Chemistry
• Fire Safety Engineering

Background:

• Rigid polyurethane foams (RPURF) are widely used for thermal insulation.
• Developing sustainable and flame-retardant materials is crucial for reducing environmental impact and enhancing safety.
• Bio-based polyols offer a renewable alternative to petroleum-based feedstocks in polymer synthesis.

Purpose of the Study:

• To synthesize and characterize bio-based rigid polyurethane foams (RPURF) using rapeseed oil polyol.
• To evaluate the effect of different phosphorus-based flame retardants (Triethyl phosphate (TEP), dimethyl propane phosphonate (DMPP), and Addforce CT 901) on foam properties.
• To assess the flammability and thermal insulation performance of the modified RPURF.

Main Methods:

• Synthesis of RPURF incorporating rapeseed oil bio-polyol and phosphorus flame retardants (TEP, DMPP, Addforce CT 901).
• Analysis of foaming process parameters, cell structure, and physical-mechanical properties (e.g., compressive strength).
• Evaluation of flammability using oxygen index and cone calorimeter tests; measurement of thermal conductivity.

Main Results:

• Flame retardant addition modified cellular structure and reduced compressive strength but maintained low thermal conductivity suitable for insulation.
• All modified RPURF samples achieved an oxygen index above 21 vol%, classifying them as self-extinguishing.
• Cone calorimeter tests indicated reduced fire development tendency in modified foams, especially those with DMPP, compared to reference foams.

Conclusions:

• Bio-based RPURF synthesized with phosphorus flame retardants demonstrate promising self-extinguishing characteristics and reduced fire hazard.
• These materials retain good thermal insulation properties, making them suitable for sustainable and safer insulation applications.
• The choice of flame retardant, particularly DMPP, significantly influences fire performance.