Recovery of Flexible Polyurethane Foam Waste for Efficient Reuse in Industrial Formulations

Abstract

<jats:p>Ester polyurethane (PU) foam waste was reacted at atmospheric pressure in an autoclave and using microwaves with diethylene glycol (DEG) at different PU/DEG ratios in the presence of diethanolamine as a catalyst to find the glycolysis conditions that allow for the improved recovery of the PU foam waste and enable the recycling of the whole glycolysis product in foam formulations suitable for industrial application. The recycled polyol was characterized by dynamic viscosity, hydroxyl number, water content, and density, while thermal stability was assessed using thermogravimetric analysis. In the PU foam formulation, 1% and 5% of the glycolyzed material was reused. The relationship between the reuse level of the recycled polyol and the physical properties of the foam was thoroughly investigated. It was observed that both hardness and air flow decreased with increasing recycled polyol content, particularly for the polyester type foam, while tensile strength and compression strength increased. Depending on the amount of recycled polyol and catalyst used, polyether-based foams could be obtained with a low air permeability, needed in special applications as sealed foams, or with higher air permeability desirable for comfort PU foams. The results open the way for further optimization studies of industrial polyurethane foam formulations using a glycolysis process without any separation stage.</jats:p>

Advances in Low-Density Flexible Polyurethane Foams by Optimized Incorporation of High Amount of Recycled Polyol

“…In our previous work [ 25 ], we demonstrated the possibility of recovering polyester-type foam waste by various glycolysis procedures and successfully reusing it without a purification step. Despite the important outcome of full reuse of the glycolysis product, the main shortcoming was the limitation to utmost 5% recycled polyol incorporated back in the flexible polyurethane foam.…”

“…Our previous paper reported a new approach that allows for the reutilization of the whole glycolysis product for producing flexible PU foam, but the incorporation of the recycled polyol back into low-density flexible PU foams was possible only in limited amounts, up to 5% [ 25 ]. Therefore, the main aim of the present work was to identify new ways to increase the recycled polyol amount, replacing fossil-based polyols, to produce flexible polyurethane foams in low-density formulations.…”

Analysis and Economic Evaluation of the Use of Recycled Polyamide Powder in Masonry Mortars

“…At present, there is an international agreement about the necessity of sustainable development with the aim of a more efficient employment and management of the limited natural resources, which includes the promotion of recycling and reuse of waste materials [ 1 ]. For plastics and polymers, which are two of the main industrial byproducts and home waste materials [ 2 ], various processes are being conducted to reuse and recycle them, such as mechanical recycling (secondary polymers are obtained through mechanical processes), chemical recycling (monomers are recovered to be employed as new virgin polymers or are transformed in other useful materials), and energy recovery (energy is obtained from the combustion of post-consumer plastics) [ 3 , 4 , 5 , 6 , 7 ]. Additionally, the introduction as fillers in other materials is becoming a possible solution for plastic and polymeric waste materials, especially in construction materials, with examples of reuse in various structural materials, such as concrete [ 8 , 9 , 10 , 11 , 12 , 13 ], mortars [ 14 , 15 , 16 , 17 , 18 ], bituminous materials for pavements [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], and gypsum [ 31 , 32 , 33 , 34 , 35 , 36 ].…”

Glycolysis of Polyurethanes Composites Containing Nanosilica

“…Polyurethanes (PUs) are the sixth most used polymers group all over the world with a production of 22.3 million tons per year [ 1 , 2 , 3 , 4 ]. The PUs compounds are generally thermoset polymers whose synthesis consists in the reaction of nucleophilic addition between a multifunctional alcohol (polyol) and a di- or tri-isocyanate, resulting in a reticular urethane structure [ 4 , 5 , 6 ], as shown in reaction (1).…”