The advancement of bis(2-hydroxyethyl)terephthalate recovered from post-consumer poly(ethylene terephthalate) bottles compared to commercial polyol for preparation of high performance polyurethane

Abstract

The behavior of rPUf (polyurethane foam derived from bis(2-hydroxyethyl) terephthalate (BHET) recovered from post-consumer poly(ethylene terephthalate)-PET bottles) and cPUf (polyurethane foam based on a commercial polyol) were evaluated by comprehensive characterizations, and their thermal stabilities, flammabilities, and physical properties were compared. Without using a flame retardant, rPUf passed the UL-94HB standard, whereas cPUf burned rapidly to the holding clamp. Various formulations of rPUf and cPUf with established eco-friendly fire retardants (FRs), including triphenyl phosphate, aluminum diethylphosphinate, and aluminum trihydroxide, exhibited notably higher fire resistance. The differences between the experimental and calculated densities showed the effectiveness of the foaming process. A larger difference indicated that the FR improved the foaming process more. The BHET structure contains an aromatic moiety that strongly enhanced the compressive strength and protected the rPUf/FRs from biodegradation, as evidenced by sorption isotherm experiments. For that reason, the rPUf/FRs could be used as building materials, especially under high humidity conditions. These are the advantages of BHET over the commercial polyol for PUf preparation. Chemical recycle of post-consumer PET bottles to produce high performance PUf could be applied on an industrial scale and then it creates the sustainable recycling industry.