GREEN CHEMISTRY
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2024
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IF 9.3
Ze-Yong Zhao,Ji Lan,Cong Deng,Yu-Zhong Wang
Polyamides (PAs) represent a class of polymers that are suitable for chemical recycling, where the amide group acts as a reactive site for degradation agents. However, the inherent stability of the amide group means that chemical recycling of PAs often necessitates stringent conditions, such as high temperatures and pressures, significantly hindering advancements in PA chemical recycling. Moreover, the effectiveness of chemically recycling polyamides into monomers or oligomers—essential components for subsequent polymer synthesis—has not been conclusively verified through comprehensive research. Here, we present the first demonstration of a method for the upcycling of PA6 into high-performance PA derivatives. In the proposed method, PA6 is fist degraded into oligomers with reactive end groups via glycolysis, with the reactivity of the resulting glycolysates subsequently verified. This oligomer acts as an intermediate in thermoplastic polyamide elastomer (TPAE) synthesis, facilitating direct integration with flexible polyethylene glycol oligomers into TPAE without requiring further degradation to monomers. The mechanical properties of the resultant TPAEs are commensurate with those previously reported for PA6-based TPAEs. By fine-tuning the reaction time and catalyst concentration, it is possible to control the molecular weight of the PA6 glycolysates, thus adjusting the TPAE’s mechanical properties. This study presents an innovative approach that seamlessly combines the degradation process of PA6 with the synthesis pathway of TPAE, thus achieving the cost-effective upcycling of PA6 into TPAE.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2016
·Vol. 147
·期 1
·240-252
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IF 2.294
Suo Qianqian,Zi Jiangzhi,Bai Zilong,Qi Shoushan
Abstract Three metal organic framework catalysts (ZIF-8, ZIF-67, MOF-5) were prepared and used in the glycolysis of poly(ethylene terephthalate) (PET). All catalysts showed excellent catalytic activities, especially ZIF-8. The raw material ratio in ZIF-8 catalysts was optimized. The effects of reaction conditions on the conversion of PET and yield of bis(hydroxyethyl) terephthalate (BHET) were examined. Graphical Abstract In the presence of ZIF-8, the PET pellets can be fully degraded within 1.5 h at 197 o C, and the main product and by-products were proved to be BHET monomer and its dimers, respectively.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Xin Wei,Jingwen Qiu,Han Wang,Weizhong Zheng,Weizhen Sun,Ling Zhao
Polyethylene terephthalate (PET) can be depolymerized using glycolysis process into bis(hydroxyethyl) terephthalate (BHET) monomer under relatively mild conditions to realize the closed-loop recycling of PET waste plastics. However, commonly used metal-based catalysts not only bring serious negative impacts on the environment, but also the residue of metals can affect the further application of products. In this work, a green and highly active 1,5-diazabicyclo[4.3.0]non-5-ene deep eutectic solvent (DBN-DESs) was developed for efficient glycolysis of PET. The optimal reaction conditions of PET glycolysis were obtained with 100 % conversion rate of PET and 78.7 % yield of BHET, respectively. The analysis of molecular weight distribution of depolymerized products shows that the glycolysis of PET varies from heterogeneous process to homogeneous process, following the shrinking-core model. First-order reaction kinetic of PET glycolysis with DBN/urea was further built with the activation energy of 155.65 kJ/mol. In particular, the catalytic mechanism of PET glycolysis by DBN/urea was analyzed in details, which reveals that DBN/urea can promote the swelling behavior of PET, and the hydrogen-bonding interaction between DBN/urea, EG and PET can also enhance the attack of hydroxyl oxygen in EG on carbonyl carbon in PET to easily breaking the ester group of PET, thus accelerating PET glycolysis.
研究领域:
材料科学
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环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Taishun Yang,Hao He,Shiyu Yan,Jiaojiao Gao,Zixu Yang,Jing Xu
The glycolysis of poly(ethylene terephthalate) (PET), a polymer extensively used in food packaging, into bis(2-hydroxyethyl) terephthalate (BHET) monomers was investigated using mesoporous silica supported by metal oxide as catalysts. Among these, a catalyst composed of ZnO supported on KIT-6 (5%ZnO/KIT-6) showed an effective performance in PET glycolysis, achieving a BHET yield of 92.1% with complete conversion of PET. Additionally, the catalyst demonstrated exceptional reusability and high efficiency in handling post-consumer PET plastics, with BHET yields reaching up to 89%. Characterization studies revealed that the highly dispersed ZnO nanoparticles trapped in KIT-6 channels formed strong interactions with surface Si-OH groups, leading to an enhanced acid strength and an increased number of acid sites, which significantly improved PET depolymerization. This study presents an innovative solution for the recycling of PET plastic, contributing to industrial development and reducing the impact of plastic waste.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2021
·
IF 4.598
Tianlin Wang,Yue Zheng,Guangren Yu,Xiaochun Chen
The catalytic effect of nanoparticles was significantly affected by its size and surface property. In this work, a series of ionic liquids were synthesized and used as surfactant to modify CoFe 2 O 4 MNP. XRD, FT-IR, TEM and VSM were performed to characterize modified CoFe 2 O 4 . The modified CoFe 2 O 4 MNP with average size of 7 nm was obtained and it was so well dispersed in ethylene glycol that ethylene glycol based magnetic fluid was obtained. Modified CoFe 2 O 4 MNP was used as catalyst for glycolysis of PET and showed excellent catalytic effect. The influence of ionic liquids surfactant and experimental factors on glycolysis were investigated. Under optimal condition, PET (5 g), catalyst (CoFe2O4/C10-OAC, 0.1 g) and EG (25 g) at 195 °C for 2.5 h, the PET conversion was 100% and BHET yield was 95.4%. More importantly, this catalyst can be collected by external magnetic field and its catalytic effect did not obviously decrease after it was reused for ten times. This work provided a new type of highly efficient catalyst of glycolysis of PET.
研究领域:
材料科学
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化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Xin Wei,Weizhong Zheng,Weizhen Sun,Ling Zhao
The swelling behaviors are critical for the effective alcoholysis of poly(ethylene terephthalate) (PET). However, understanding the swelling behaviors of PET in alcohol solvents is still limited. Hence, the interfacial and swelling behaviors for PET mixed alcoholysis with ethylene glycol/1,4-cyclohexanedimethanol (EG/CHDM) were studied by combining experiments and molecular dynamics (MD) simulations. The results of MD simulation indicate that introducing CHDM (EG/CHDM = 4:1) can promote PET swelling, increase interfacial thickness, and enhance diffusion behaviors of end groups and main chains of PET, in which EG/CHDM molecules obviously move into the bulk regions of the PET phase. These results of experimental characterization and kinetics also indicate that the introduction of CHDM (EG/CHDM = 4:1) can improve the surface roughness of PET particles and increase the effective contact area, thus accelerating the glycolysis rate of PET particles with lower activation energies compared with the pure PET glycolysis. This information provides a better understanding of the swelling behaviors of PET in the alcoholysis process.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
IRANIAN POLYMER JOURNAL
·
2024
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IF 2.4
Wang Jiawei,Chen Yanming,Li Liang,Wang Liyan,Qian Xin
Chemical depolymerization and recycling of waste polyethylene terephthalate (PET) fibers represent an optimal sustainable approach. However, the presence of dyes in the fibers and the use of conventional homogeneous catalysts may have a detrimental impact on the depolymerization products. In this investigation, solvent extraction was employed to meticulously remove dispersed dyes from waste PET fibers, serving as a crucial preparatory step for subsequent chemical depolymerization. This process was followed by the synthesis of spherical hexagonal Wurtzite zinc oxide (ZnO) nanocrystals through a meticulously refined solution chemical method, with careful consideration given to the potential impacts of surface modification and the alcohol-water ratio on the morphological attributes and particle size distribution of these nanocrystals. These ZnO nanocrystals were subsequently utilized as a pseudo-heterogeneous catalyst, catalyzing the glycolysis of decolorized waste PET fabrics. Systematic investigations were conducted to elucidate the intricate relationships between the morphologies, particle sizes, and concentrations of ZnO nanocrystals and their corresponding catalytic activities, leading to the identification of optimal reaction conditions through a series of conditional experiments. Under these optimized conditions, namely a catalyst concentration of 0.5% (by weight), a reaction temperature of 195 °C, and a duration of 30 min, a remarkable yield of bis (2-hydroxyethyl) terephthalate (BHET) was achieved, reaching 82.07%, with a corresponding mass fraction of 97.62%. Graphical abstract
研究领域:
化学工程
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Dandan Lei,Xiao-Li Sun,Shasha Hu,Huibin Cheng,Qinghua Chen,Qingrong Qian,Qiao Xiao,Changlin Cao,Lireng Xiao,Baoquan Huang
Recycling waste polyethylene terephthalate (PET) fibers is critical for both environmental and resource protection. However, the PET fiber possesses good chemical stability and high crystallinity, resulting in the conversion of PET. Herein, we developed a strategy of stepwise feeding process to recycle PET fibers and recover the potential monomer by adding it to the glycolysis agent diethylene glycol after it had been warmed up to reaction temperature. The results show a significant increase in the PET fiber conversion (92.5%) and yield of water-soluble products (70.4%) in 90 min as compared to a one-step feeding process of 28 and 14.4%, respectively. These water-soluble products are monomers and dimers which are confirmed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, mass spectroscopy, and high-performance liquid chromatography. It is also obviously found that the conversion of PET and yields of fibers are lower than those of bottle flakes and particles. In addition, a ’column shrinkage model’ is proposed to describe the glycolysis process of the fibers. The apparent reaction activation energy of fibers was derived as 27.19 kJ/mol, which is somewhat higher than those of PET bottle flakes and particles.
研究领域:
化学工程
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环境科学
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材料科学
✓ 已验证
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2022
·
IF 5.204
Wenyan Chen,Maoxin Li,Xinchen Gu,Liang Jin,Wenxing Chen,Shichang Chen
s The recycling of discarded polyethylene terephthalate (PET) is an effective way of catering to global sustainable economic development strategies. It is well known that catalysts play a crucial role in the degradation of PET, based on the fact that most of the currently available catalysts have some disadvantages, including complex preparation process, severe reaction conditions and insufficient reaction efficiency. Herein, we report a combination of metal catalyst and organoazacyclic 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU) as cooperating catalysts were used to depolymerize waste polyethylene terephthalate into bis(2-hydroxyethyl) terephthalate (BHET) directly. Screening of several metal salts under optimal conditions showed that zinc acetate ((Zn(OAc) 2) was the most effective co-catalyst. The waste PET could be completely depolymerized at 180 °C for 77 min with the weight ratio of EG/PET was 3:1 and the molar ratio of Zn(OAc) 2 /DBU was 1:2, and the content of BHET in the recrystallized product reached 78.2%. Kinetic studies showed that the activation energy of depolymerization of PET was 115.48 kJ/mol. It was speculated that the hydrogen bond formed by Zn(OAc) 2 /DBU and EG exhibited excellent catalytic effect in the glycolysis process. Therefore, it is hopeful that this simple and mild composite catalyst can provide industrial ideas for recycling other waste polyesters.
研究领域:
材料科学
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2025
·
IF 3.9
Xiao-Xuan Peng,Ze-Peng Bai,Kang Wu,Hua Zou,Hang-Tian Zhang,Jie-Xin Wang
The escalating global demand for poly(butylene terephthalate) (PBT), as one of the five major engineering plastics, has led to severe ecological crises and significant resource consumption. In this work, we employ 1,4-butanediol dispersions of ultrasmall zinc oxide nanoparticles (ZnO NPs) with an average size of 2.8 nm and excellent dispersity as catalysts for the highly efficient glycolysis of PBT using 1,4-butanediol. Specifically, complete depolymerization of PBT and approximately 98% yield of bis(4-hydroxybutyl) terephthalate (BHBT) are achieved within 45 min at 200 °C by only a minimal amount of ZnO NPs (0.1 wt %). More importantly, 95% PBT conversion can still remain after five cycles, exhibiting high recyclability of ZnO NPs. The possible reaction mechanism for glycolysis of PBT in 1,4-butanediol over ZnO NPs is proposed, and the reaction kinetics is also studied with an activation energy of 149.7 kJ/mol. Furthermore, ZnO NPs also show outstanding catalytic activity in the methanolysis of PBT, reaching over 97% yield of dimethyl terephthalate (DMT) within 60 min at 160 °C. This work provides a sustainable pathway for efficient recycling and reuse of PBT and broadens its market prospect.
研究领域:
材料科学
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催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）