Polyurethane waste recycling. 1. Glycolysis and hydroglycolysis of water-blown foams

Gerlock, John L.; Braslaw, J.; Zinbo, M.

doi:10.1021/i200026a023

Cited by 56 publications

(58 citation statements)

References 7 publications

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“…Additionally, recent research has demonstrated that the choice of catalyst is an important factor affecting the properties of the recovered products, as well as the temperature to reach the complete degradation. Catalysts used in polyurethane glycolysis include bases such as amines, hydroxides, and alkoxides, as well as Lewis acids [23][24][25], leading to secondary reactions in different extension. In addition, acetates of potassium and sodium have also been used as catalysts in the case of transesterification of urethane bonds with glycols [2].…”

Section: Introductionmentioning

confidence: 99%

Chemical degradation of thermoplastic polyurethane for recycling polyether polyol

Wang

Chen

Chen³

et al. 2011

Fibers Polym

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Thermoplastic polyurethane, based on 4,4'-diphenylmethane diisocyanate and polyether polyol, was degraded by glycol and ethanolamine at 170 o C. Optimum conditions for the glycolysis of thermoplastic polyurethane were investigated by adjusting the ratio of polymer to degradation reagent, glycol to ethanolamine as well as the reaction temperature. The degradation reaction was conducted under nitrogen atmosphere and accelerated by catalysts such as lithium acetate, which was evidenced by lowering the degradation temperature as well as the amounts of degradation reagent. The decomposition products were completely separated into two layers. The upper liquid layer was a polyether polyol, which was characterized by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The present glycolysis procedure allows a simple recycling of the hydroxyl terminated polyol in pure form.

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Section: Introductionmentioning

confidence: 99%

Chemical degradation of thermoplastic polyurethane for recycling polyether polyol

Wang

Chen

Chen³

et al. 2011

Fibers Polym

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“…Hydrolysis, treatment with esters of phosphoric acid, aminolysis with low weight alkanolamines and glycolysis have been described as suitable procedures to break down the polyurethane chain [3][4][5][6][7][8][9]. Most of these processes produce a liquid mixture of compounds with hydroxyl active groups, which can be used only in blending with raw materials to obtain low quality products.…”

Section: Introductionmentioning

confidence: 99%

Chemical recovery of flexible polyurethane foam wastes

Molero

Ramos

Lucas

et al. 2010

WIT Transactions on Ecology and the Environment

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The development of a chemical process for the recovery of polyols from flexible polyurethane foam wastes with enough quality to be reutilized in foaming has been a major challenge for scientists during recent years. In that way the objective of chemical recycling of PU wastes is the recovery of its major constituent, the polyol, in an environmental friendly way that is performed with the lowest cost and without hazardous residues production. The glycolysis of PU wastes in the presence of a large excess of glycolitic agent allows one to obtain a polyol rich upper phase and a bottom phase containing mainly glycol and isocyanate derivatives. Different metal octoates derived from cycloaliphatic carboxylic acids can be used as the catalyst with suitable catalytic activity. The optimization of process conditions has demonstrated that there is a narrow window of process conditions (relation between phases, temperature, catalyst, etc) in which the split phase glycolysis can be carried out. The recovered polyols have to be subjected to purification by aqueous liquid-liquid extraction before refoaming in a conventional formulation mixed with fresh ones in a large range of proportions. The excess of glycolyzing agent in the bottom phase has to be returned to the cycle by vacuum distillation. The vacuum residue containing the isocyanate derivatives can be applied as an initiator in the synthesis of rigid polyols, allowing the complete use of the glycolyzates from PU recycling.

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“…Although it is more expensive than conventional glycolysis as the purification of the polyol-rich product is more complicated. It has the advantage that complex mixtures of dirty and contaminated PU wastes can be processed as well, which otherwise would have to be land filled [123]. The recovered polyol may replace up to 50% of virgin polyol material for PUF foams.…”

Section: Other Chemical Recycling Methodsmentioning

confidence: 99%

Polyurethane Waste Reduction and Recycling: From Bench to Pilot Scales

Nikje

Garmarudi

Idris

2011

Designed Monomers and Polymers

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In this review, reports, patents and recently published papers and documents on polyurethane recycling, especially chemical recycling methods, are investigated in order to find an adequate method for waste reduction, protecting the environment and preventing waste land filling. The recycling of polyurethane has always posed unique challenges due to its wide variety of applications, from the industry to bio-based materials, namely, artificial organs. Mechanical regrinding is the oldest method in polyurethane waste recycling and the use of the regrind wastes as filler in the new formulations. Chemical recycling of polyurethanes by hydrolysis, aminolysis and glycolysis is for the most part considered economically uncompetitive compared to formulating with virgin raw materials. Also some thermochemical processes are utilized for PU recycling. Recycling has opened an effective and economic route for polyurethane waste treatment. Nonetheless, more research efforts are required in order to scale up the recycling methods.

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Polyurethane waste recycling. 1. Glycolysis and hydroglycolysis of water-blown foams

Cited by 56 publications

References 7 publications

Chemical degradation of thermoplastic polyurethane for recycling polyether polyol

Chemical degradation of thermoplastic polyurethane for recycling polyether polyol

Chemical recovery of flexible polyurethane foam wastes

Polyurethane Waste Reduction and Recycling: From Bench to Pilot Scales

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