Regeneration of ?-caprolactam from wastes in the manufacture of polycaproamide fibres and yarns

Дмитриева, Л. А.; Speranskii, A. A.; Krasavin, S. A.; Bychkov, Yu. N.

doi:10.1007/bf00545638

Cited by 4 publications

(2 citation statements)

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“…More recently, Datye (4) reviewed the depolymerization of waste nylon generated during the manufacturing of nylon 6 and filament yam. Another review on the topic of e-caprolactam regeneration from wastes in the manufacture of nylon fibers and yams has also been published by Dmitrieva et aL (9). In the following paragraphs we provide a summary of the most important issues related to the depolymerization process as applied to the recovery of nylon from carpet waste and review the more recent developments in this area.…”

Section: 2 Depolymerizationmentioning

confidence: 98%

Review: Recycling of nylon from carpet waste

Mihut

Captain

Gadala-Maria

et al. 2001

Polymer Engineering & Sci

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Large amounts of post‐consumer carpet are discarded every year. Most of this waste is currently landfilled, while a small percentage is incinerated. The face carpet fibers, consisting primarily of nylon 6 and nylon 6,6, represent the majority component in the carpet waste. Recent financial incentives and environmental constraints have motivated the industrial sector to develop recycling strategies for these fibers. Depolymerization into their constituent monomers is the most complex recycling route, but at the same time it produces the most valuable product. A second alternative involves the use of solvents for the extraction of carpet fiber components in their polymeric form. Finally, a third recycling option yields thermoplastic mixtures by melt blending the carpet waste. The recent literature on the recycling of nylon from carpet waste is reviewed in this paper. The paper also includes a section focusing on the current state of carpet recycling at the Industrial level.

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Section: 2 Depolymerizationmentioning

confidence: 98%

Review: Recycling of nylon from carpet waste

Mihut

Captain

Gadala-Maria

et al. 2001

Polymer Engineering & Sci

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“…However, the sublimation tendency of the oligomers produced or the use of corrosive catalysts poses problems. Dmit-rieva and coworkers [5][6][7][8] reviewed the catalytic depolymerization of nylon 6 waste with superheated vapor.…”

Section: Introductionmentioning

confidence: 99%

Depolymerization of nylon 6 waste fibers

Shukla

Harad

Mahato

2006

J of Applied Polymer Sci

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ABSTRACT:The depolymerization of nylon 6 was carried out with various solvents, such as formic acid, hydrochloric acid, and sulfuric acid, followed by heating under reflux for different times. From the polymer dissolved and refluxed in formic acid, degradation products with different ranges of molecular weights were collected by fractional precipitation, with small lots of distilled water added as a nonsolvent. The characterization of different fractions was carried out by the measurement of the viscosity-average molecular weight, the number-average molecular weight, and the number of amino end groups. The presence of the monomer, aminocaproic acid, was confirmed by thin-layer chromatography in the case of hydrochloric acid treated nylon 6. With a strongly acidic ion-exchange resin, the monomer was separated in its purest form, and the melting point was noted.

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Assessment of Nylon-6 Depolymerization for Circular Economy: Kinetic Modeling, Purification, Sustainable Process Design, and Industrial Practice

McNeeley,

Liu

2024

Ind. Eng. Chem. Res.

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Nylon-6 is a commonly produced plastic that has found a wide range of applications in carpets, textiles, electronics, and automotive parts. Chemical depolymerization to form the nylon-6 monomer caprolactam (CL) has been practiced to recover oligomers and postindustrial nylon-6 waste. There is a growing interest in developing and improving processes for closed-loop recycling of postconsumer nylon-6 waste. This work presents a comprehensive assessment of the three primary types of nylon-6 depolymerization processes: liquid-phase hydrolysis, steam stripping, and solvent-free depolymerization. This study is unique in providing a thorough assessment of both the academic literature and industrial patents. We develop depolymerization kinetic models and suggest further experimental measurements for determining reaction mechanisms and discuss industrial practice of crude CL purification methodologies and waste management strategies. We develop for the first time detailed Aspen Plus simulation models incorporating thermodynamic and kinetic modeling, impurity separation, product purification, and waste minimization to provide the quantitative foundation for sustainable design of all three types of depolymerization processes. We identify where there are uncertainties in design and modeling and where gaps in data currently exist. Finally, we implement heat integration and process intensification to reduce utility demand and CO 2 emission, enhance the sustainable design, and provide quantitative comparison of depolymerization process options in terms of energy demands and CO 2 emission, among others.

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Regeneration of ?-caprolactam from wastes in the manufacture of polycaproamide fibres and yarns

Cited by 4 publications

References 4 publications

Review: Recycling of nylon from carpet waste

Review: Recycling of nylon from carpet waste

Depolymerization of nylon 6 waste fibers

Assessment of Nylon-6 Depolymerization for Circular Economy: Kinetic Modeling, Purification, Sustainable Process Design, and Industrial Practice

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