Recycling of polyurethane scraps via acidolysis

Gama, Nuno; Godinho, Bruno; Marques, Gerson Reginaldo; Silva, R.; Barros‐Timmons, Ana; Ferreira, Artur

doi:10.1016/j.cej.2020.125102

Cited by 92 publications

(92 citation statements)

References 27 publications

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“…The recycling of PUF was carried out as previously reported 15 consisting in the reaction of PUF scraps with DA and the conventional polyol in a 5 L Chemglass reactor, under mechanical stirring at atmosphere pressure. In Table 4, the reaction conditions are listed.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, a method for the recycling of PU, the acidolysis, was reported in which DA are used as cleavage agents 15 . The DA reacts with the carbamic group of PU, depolymerized it into polyols and/or other oligomers, according to Scheme 1 10,15 …”

Section: Introductionmentioning

confidence: 99%

“…Recently, a method for the recycling of PU, the acidolysis, was reported in which DA are used as cleavage agents. 15 The DA reacts with the carbamic group of PU, depolymerized it into polyols and/or other oligomers, according to Scheme 1. 10,15 Where R 1 and R 3 correspond to the polyol moieties of the PU chains, R 2 corresponds to the isocyanate moieties of the PU chains and R 4 corresponds to the dicarboxylic acid moieties.…”

Section: Introductionmentioning

confidence: 99%

“…15 The DA reacts with the carbamic group of PU, depolymerized it into polyols and/or other oligomers, according to Scheme 1. 10,15 Where R 1 and R 3 correspond to the polyol moieties of the PU chains, R 2 corresponds to the isocyanate moieties of the PU chains and R 4 corresponds to the dicarboxylic acid moieties. Although some reports related with this chemical recycling method have been previously published, 14,17,18 it was the first time that the main degradation mechanisms and chemical reactions involved were reported.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Recycling of polyurethane wastes using different carboxylic acids via acidolysis to produce wood adhesives

Godinho

Gama

Barros‐Timmons

et al. 2021

Journal of Polymer Science

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This study aims to provide further understanding on the depolymerization of polyurethanes (PU) via acidolysis. Therefore, polyurethane foams scraps are chemical recycled using different dicarboxylic acids, namely succinic and phthalic dicarboxylic acids, being the reaction products identified using Fourier‐transform infrared spectroscopy, nuclear magnetic resonance and gel permeation chromatography. The results obtained show that succinic acid has higher efficiency as cleavage agent, as a result, the succinic acid ensuing recovered polyol (RP) presents higher hydroxyl value and lower viscosity. Additionally, from the oxidative‐induction time measurements, it is observed that the RP is considerably more thermally stable, than the petroleum‐based polyol, due to the higher content of aromatic moieties. Afterwards, the RP is used as substitute of petroleum‐based polyol in the production of polyurethane adhesives (PUA) and compared with conventional polyol based PUA. Due to the higher content of aromatic moieties, higher bonding strength is achieved using the RP. Overall, further understanding on the acidolysis is obtained, proving the suitability of this method for the recycling of PU.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Recycling of polyurethane wastes using different carboxylic acids via acidolysis to produce wood adhesives

Godinho

Gama

Barros‐Timmons

et al. 2021

Journal of Polymer Science

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“…[ 2,7,8 ] For example, hydrolysis of PUs can be employed in certain cases to recover the original alcohol monomer (polyol), along with the amine analogue of the original isocyanate monomer. [ 9–13 ] Similarly, various amines, [ 14–20 ] alcohols, [ 14,15,17–19,21–25 ] and acids [ 5,26–32 ] have been used to displace the carbamate linkage and thereby depolymerize PUs. Generally speaking, however, these depolymerization strategies are energy intensive, requiring high temperature, high pressure, and/or long reaction times, and they are inefficient, requiring stoichiometric quantities of cleavage reagents to yield complex mixtures of monomers and oligomers (i.e., incomplete depolymerization) that must be further separated and purified.…”

Section: Methodsmentioning

confidence: 99%

Selectively Depolymerizable Polyurethanes from Unsaturated Polyols Cleavable by Olefin Metathesis

Jones

Staiger

Powers

et al. 2020

Macromol. Rapid Commun.

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This communication describes a novel series of linear and crosslinked polyurethanes (PUs) and their selective depolymerization under mild conditions. Two unique polyols are synthesized bearing unsaturated units in a configuration designed to favor ring‐closing metathesis (RCM) to five‐ and six‐membered cycloalkenes. These polyols are co‐polymerized with toluene diisocyanate to generate linear PUs and trifunctional hexamethylene‐ and diphenylmethane‐based isocyanates to generate crosslinked PUs. The polyol design is such that the RCM reaction cleaves the backbone of the polymer chain. Upon exposure to dilute solutions of Grubbs’ catalyst under ambient conditions, the PUs are rapidly depolymerized to low molecular weight, soluble products bearing vinyl and cycloalkene functionalities. These functionalities enable further re‐polymerization by traditional strategies for polymerization of double bonds. It is anticipated that this general approach can be expanded to develop a range of chemically recyclable condensation polymers that are readily depolymerized by orthogonal metathesis chemistry.

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Foam‐to‐Foam Recycling Potential of PU‐Foams by Integration of Amino Esters

Kassem,

Samat,

Imbernon

et al. 2024

Adv Funct Materials

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The increasing market demand for flexible polyurethane foams (PUFs) is prompting the academic and industrial community to seek solutions for their end‐of‐life management. In this study, this issue is addressed by incorporating β‐amino ester (BAE) moieties into the foam structure. This addition results in flexible hybrid PU‐BAE foams that can be thermally reprocessed and chemically recycled, with cell sizes ranging from 780 to 990 µm and densities between 90 and 150 kg m−3. These foams demonstrate thermomechanical reprocessability, yielding stable PU‐BAE elastomers, with glass transition temperature values ranging from 14 to 25 °C. Stress relaxation experiments reveal remarkably fast relaxation times for these hybrid elastomers (23 s at 160 °C). Furthermore, a systematic investigation of the chemical recyclability of these foams via glycosylation is conducted under mild conditions, achieving complete disintegration within 20 min at 65 °C. Finally, the chemically recycled product is converted into a foam again, achieving a closed loop foam‐to‐foam recycling process. These findings indicate that the integration of BAE into PUFs leads to an enhanced chemical recycling rate, providing a promising avenue for addressing end‐of‐life concerns in PUF‐applications.

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Recycling of polyurethane scraps via acidolysis

Cited by 92 publications

References 27 publications

Recycling of polyurethane wastes using different carboxylic acids via acidolysis to produce wood adhesives

Recycling of polyurethane wastes using different carboxylic acids via acidolysis to produce wood adhesives

Selectively Depolymerizable Polyurethanes from Unsaturated Polyols Cleavable by Olefin Metathesis

Foam‐to‐Foam Recycling Potential of PU‐Foams by Integration of Amino Esters

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