Closed-Loop Recycling of Poly(vinyl butyral) Interlayer Film via Restabilization Technology

Area of Science:

• Polymer Science
• Materials Chemistry
• Sustainable Materials

Background:

• Polyvinyl butyral (PVB) is crucial in laminated glass but lacks end-of-life recycling solutions.
• PVB degradation under heat and shear limits its recyclability.

Purpose of the Study:

• To develop a comprehensive recycling strategy for post-consumer PVB waste.
• To identify effective antioxidant formulations for PVB stabilization during remelting.

Main Methods:

• Analysis of PVB thermo-oxidative degradation mechanisms (chain scission) via MFR, IV, and YI.
• Screening of six antioxidant formulations for efficacy in plasticized and unplasticized PVB.
• Upscaling the recycling process using a twin-screw extruder with optimized antioxidant concentrations.

Main Results:

• Identified chain scission as the primary degradation mechanism for PVB.
• Two specific phenolic antioxidants demonstrated superior performance in inhibiting PVB degradation.
• Optimal antioxidant concentration determined at 0.3% w/w, with successful upscaling and validation of recycled PVB.

Conclusions:

• A viable remelting-restabilization strategy for PVB recycling has been established.
• Selected antioxidants effectively protect PVB during reprocessing and enhance its service life.
• This approach offers a circular economy solution for PVB waste materials.