From Construction Industry Waste to High-Performance Insulation: Sustainable Rigid Polyurethane Foams with Recycled...

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Engineering

Background:

• Polyurethane (PU) waste from the building industry presents disposal challenges.
• Developing circular economy strategies for PU materials is crucial for sustainability.
• Rigid PU foams are vital for thermal insulation, but virgin material production has environmental costs.

Purpose of the Study:

• To assess the feasibility of using chemically recycled polyol (glycolysate) from PU waste in rigid foam formulations.
• To evaluate the impact of glycolysate incorporation on foam properties and performance.
• To determine the potential for resource efficiency and reduced carbon footprint in insulation materials.

Main Methods:

• Chemical recycling of semi-rigid PU waste into polyol (glycolysate) via glycolysis.
• Formulation of rigid PU foams with varying percentages (5-50%) of recycled polyol.
• Characterization of foam properties: foaming kinetics, cellular structure, thermal conductivity, mechanical strength, dimensional stability, flammability, and VOC emissions.

Main Results:

• Glycolysate incorporation accelerated foaming and reduced catalyst requirements.
• Up to 40% recycled polyol substitution maintained high closed-cell content (87.7%), low thermal conductivity (26.3 mW/(m·K)), and excellent dimensional stability (<1%).
• Compressive strength increased by 30% (294 kPa vs. 208 kPa), flammability met B2 classification, and no additional harmful VOCs were detected.

Conclusions:

• Recycled polyol (glycolysate) is a viable component for high-performance rigid PU insulation foams.
• Utilizing glycolysate enhances resource efficiency and contributes to a reduced carbon footprint.
• This study demonstrates a promising pathway for valorizing PU waste into valuable insulation materials.