Mechanism of glycolysis of nylon 6,6 and its model compound by ethylene glycol

Kim, Kap Jin; Dhevi, D. Manjula; Lee, Jong Soon; Cho, Young Dal; Choe, Eun Kyung

doi:10.1016/j.polymdegradstab.2005.09.019

Cited by 26 publications

(18 citation statements)

References 7 publications

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“…At the beginning of the process, the oligomeric compounds with the hydroxyl and/or amine end-groups are obtained. In the final stage, the mixture of low-molecular-weight products, specifically unreacted ethylene glycol, hexamethylenediamine or a compound with β-hydroxyethylester end-groups can be obtained [5,28].…”

Section: Characterization Of Glycolysates and Aminoglycolysatesmentioning

confidence: 99%

“…Polyamides (PAs) are a group of crystalline polymers which are commonly represented by two commercial products, i.e. polyamide 6 (nylon 6) and polyamide 6.6 (nylon 6.6) [5]. The most common types of polyamide are obtained in the form of fibres or thermoplastics [6].…”

Section: Introductionmentioning

confidence: 99%

“…The hydrolytic route (ring-opening polymerization) is used to form polyamide 6, while polyamide 6.6 is obtained via stepgrowth reactions between diamines and diacids [8]. Polyamides are characterized by high chemical resistance, and good mechanical and thermal properties [5,9]. In order to improve the properties of aliphatic polyamides, the incorporation of aromatic moiety into an aliphatic backbone is applied [8].…”

Section: Introductionmentioning

confidence: 99%

“…The reactivity of polyamides depends on the polar amide groups present in the main polyamide chain, which can react with decomposing agents. The typical decomposing agents are ammonia (ammonolysis) [19,20], water or steam (hydrolysis) [3,[21][22][23] and glycols (glycolysis) [5]. The products of the decomposition of polyamide are oligomers or small-molecular-weight chemical compounds with different physicochemical properties and functionality.…”

Section: Introductionmentioning

confidence: 99%

“…Up to now, the glycolysis of nylon 6 was studied more accurately [26,27]. Kim et al [5] examined the degradation mechanism of polyamide 6.6 by ethylene glycol that is based on the decomposition of the model compound, namely, N,Nhexamethylenebis(hexamide). The authors also characterized the obtained glycolysates using GPC, GC-MS, and FTIR analysis.…”

Section: Introductionmentioning

confidence: 99%

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A New Approach to Chemical Recycling of Polyamide 6.6 and Synthesis of Polyurethanes with Recovered Intermediates

et al. 2018

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A new efficient method for the chemical decomposition of polyamide 6.6 by the glycolysis and amino-glycolysis processes was proposed. The glycolysis was conducted using the mass excess of ethylene glycol (EG) as a decomposing agent in the presence of a catalyst. Also, a mixture of EG and triethylenetetramine was used as another decomposing agent in the aminoglycolysis process. The described process of decomposition did not require the use of elevated pressure. The hydroxyl and amine numbers, rheology behavior and the presence of characteristic chemical groups in the obtained glycolysates and aminoglycolysates were determined in order to characterize the reaction products. The decomposition products were defined as non-Newtonian fluids that could be described by suitable mathematical models. The conducted studies showed that the properties of the obtained intermediates depend on the mass excess of the decomposing agent used. The resulting semiproducts are suitable for reusing in the synthesis of polyurethanes, which has been confirmed by the exemplary synthesis. In the reaction, 10 and 15 wt% of commercial polyol were replaced with the recovered intermediates.

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Section: Characterization Of Glycolysates and Aminoglycolysatesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A New Approach to Chemical Recycling of Polyamide 6.6 and Synthesis of Polyurethanes with Recovered Intermediates

et al. 2018

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Organo‐sulfonic acid catalyzed degradation kinetics and thermodynamic studies of nylon‐6 by hydrothermal method

Khuntia

Gadgeel

Mestry

et al. 2021

Polymers for Advanced Techs

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Nylon-6 as an engineering polymer and its starting monomer are both costly. Chemical reutilization offers some economic and environmental benefits. Depolymerization of nylon-6 was carried out by the conventional technique of hydrothermal method using various organo-sulfonic acids such as Methane sulfonic acid (MSA), paratoluene sulfonic acid (p-TSA), benzene sulfonic acid (BSA), and tetra-butyl ammonium bromide (TBAB) as a phase transfer catalyst. Various parameters such as temperature, time, normality of acids, and phase transfer catalyst concentration were varied to optimize its parameters, and characterization techniques such as amine value titrations and Fourier transform infrared spectroscopy were used for quantitative measurements. Solid-state 13 C NMR was done for structure confirmation. A chemical kinetics interpretation shows degradation mechanism follows first-order kinetics under various catalysts. MSA has the highest reaction rate of 8.49 Â 10 À2 h À1 at 90 C; it decreases to 7.72 Â 10 À2 h À1 at 100 C. At the same time, aromatic Sulfonic acids such as p-TSA and BSA have a higher reaction rate of 8.995 Â 10 À2 h À1 and 5.582 Â 10 À2 h À1 , respectively. The activation energy was lowered as the acidity of organo-sulfonic acids increased as benzene sulfonic acid has the lowest E a. Followed by p-TSA, and MSA has the highest E a. Free energy shows a similar kind of value. A simple theoretical model was used to calculate the activation energy. Thermodynamic parameters such as heat of enthalpy and entropy of reaction were evaluated using the Eryig-Polanyi equation. The combined catalytic effect of organo-sulfonic acids and phase-transfer catalyst provides a better environment-friendly method for depolymerizing nylon-6.

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Origin of deterioration in mechanical properties of glass fiber reinforced nylon 6,6 composites by aqueous ethylene glycol solution

Hong¹,

Dhevi²,

Lee³

et al. 2007

Polymer Composites

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Glass fiber reinforced nylon 6,6 (GFNY66) composites widely used for automotive applications undergo degradation when repeatedly exposed to aqueous ethylene glycol (EG) solution, resulting in significantly reduced mechanical properties. Hence, it is important to clearly understand the degradation and hydrogen bond breaking mechanism of nylon 6,6 (NY66) and interfacial failure mechanism in GFNY66 (when exposed to aqueous EG solution) in order to improve the mechanical properties of recycled NY66. From ATR-IR spectra of NY66 immersed in aqueous EG solution at 1088C for varying intervals of time, the shifting of amide-I band (n C¼ ¼O ) at 1640 cm À1 towards lower frequency with increasing immersion time may be attributed to the breakage of intra-and intermolecular H-bonding between amides in NY66 followed by the new formation of H-bonding between amide group in NY66 and hydroxyl group in the absorbed EG. GPC data revealed the reduction in molecular weight due to the absorption of EG into NY66 matrix leading to chain scission of NY66. GFNY66 samples treated with aqueous EG solution exhibited pronounced deterioration in mechanical properties because of the interfacial failure between glass fiber and NY66 matrix as well as molecular weight reduction caused by the absorbed EG solution. POLYM. COMPOS.,

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Mechanism of glycolysis of nylon 6,6 and its model compound by ethylene glycol

Cited by 26 publications

References 7 publications

A New Approach to Chemical Recycling of Polyamide 6.6 and Synthesis of Polyurethanes with Recovered Intermediates

A New Approach to Chemical Recycling of Polyamide 6.6 and Synthesis of Polyurethanes with Recovered Intermediates

Organo‐sulfonic acid catalyzed degradation kinetics and thermodynamic studies of nylon‐6 by hydrothermal method

Origin of deterioration in mechanical properties of glass fiber reinforced nylon 6,6 composites by aqueous ethylene glycol solution

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