Improving chemical recycling rate by reclaiming polyurethane elastomer from polyurethane foam

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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“…This method was developed during 1980s [70][71][72][73][74]. Figures 8 and 9 show the schematic mechanism of the glycolysis process.…”

Section: Glycolysismentioning

confidence: 99%

Polyurethane Waste Reduction and Recycling: From Bench to Pilot Scales

Nikje

Garmarudi

Idris

2011

Designed Monomers and Polymers

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“…The reuse of these products is complicated by the presence of reticulations in the polyurethane structure, so PUr creates a great disposal problem and is highly polluting to the environment. PUr residues are not adequately reprocessed to obtain new product, as they are thermoset polymers with low density [3][4][5] . Polyvinyl butyral (PVB) is an amorphous random copolymer of vinyl butyral, vinyl alcohol, and vinyl acetate, mainly used in laminated safety glass in automotive, aerospace and architectural glass sections [6,7] .…”

Section: Introductionmentioning

confidence: 99%

Flexible thermoplastic composite of Polyvinyl Butyral (PVB) and waste of rigid Polyurethane foam

2015

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SbstractThis study reports the preparation and characterization of composites with recycled poly(vinyl butyral) (PVB) and residue of rigid polyurethane foam (PUr), with PUr contents of 20, 35 and 50 wt %, using an extruder equipped with a Maillefer single screw and injection molding. The components of the composites were thermally characterized using differential scanning calorimetry (DSC) and thermogravimetry. The composites were evaluated by melt flow index (MFI), tensile and hardness mechanical tests and scanning electron microscopy (SEM). Tg determined by DSC of PVB sample (53 °C) indicated the presence of plasticizer (Tg of pure PVB is 70 °C). MFI of the composites indicated a viscosity increase with the PUr content and, as the shear rate was held constant during injection molding, higher viscosities promoted higher shear stresses in the composites, thereby causing breaking or tearing of the PUr particles. The SEM micrographs showed low adhesion between PVB and PUr and the presence of voids, both inherent in the rigid foam and in the interphase PVB-PUr. The SEM micrographs also showed that PVB/PUr (50/50) composite exhibited the smallest particle size and a more homogeneous and compact structure with fewer voids in the interface. The stiffness of the composites increases with addition of the PUr particles, as evidenced in the mechanical tests.

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“…Polyurethane chemolysis by reaction with amines has been described in the literature. Watando has proposed a process based on polyurethane foam decomposition using Diethanolamine in an extruder and the resulting decomposed product could be used as an alternative virgin polyol in reclaiming polyurethane elastomers [3]. In an experiment by Fukaya, a reheating process for the products in the chemical recycling of rigid polyurethane foam by an extruder with diethanolamine as a decomposing agent was effective for improving the product stability [4].…”

Section: Introductionmentioning

confidence: 99%

Sustainability by Converting Waste Polyurethane Foam into Superior Polyurethane Urea Coatings

Rane¹,

Kathalewar²,

Jamdar³

et al. 2015

OALib

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Recycling is a crucial area of research in Green Polymer Chemistry and developments in recycling are driven by environmental concerns, interests in sustainability and desire to decrease dependence on petroleum based materials. Sustainability refers to the development that meets the needs of present without comprising the ability of future generations. Polyurethane foams (PU) are widely used due to their light weight and superior heat insulation as well as good mechanical properties. However, large quantities of polyurethane foam are discharged during manufacturing/ processing as a waste and hence recycling of PU foam is necessary. In present study polyurethane foam is reacted with an alkanolamines in presence of a catalystin conventional as well as microwave method, but microwaves proved to be fast to depolymerise polyurethanes foam as compared to conventional method. The rate of reaction could be made identified by comparing the hydroxyl values of the two systems. The hydroxyl value increases as the time and microwave power increases. Further the depolymerised product with specified hydroxyl and amine groups is further cured with isocyanates for coating application and the coating formed is evaluated for physical, mechanical and chemical tests.

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Improving chemical recycling rate by reclaiming polyurethane elastomer from polyurethane foam

Cited by 30 publications

References 5 publications

Polyurethane Waste Reduction and Recycling: From Bench to Pilot Scales

Polyurethane Waste Reduction and Recycling: From Bench to Pilot Scales

Flexible thermoplastic composite of Polyvinyl Butyral (PVB) and waste of rigid Polyurethane foam

Sustainability by Converting Waste Polyurethane Foam into Superior Polyurethane Urea Coatings

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