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The pyrolysis of poly (ethylene terephthalate) (PET) in the presence of ZSM-5 zeolite and NiCl as a catalyst was studied at different temperatures under N atmosphere. Quantitative C nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR) were applied to characterize the waxy and solid residue. The carboxyl and aliphatic hydroxyl groups in the waxy residue have been greatly depleted after the use of zeolite during pyrolysis on the basis of the results of C NMR and FT-IR analysis. The proportion of aromatic hydroxyl groups increased by 21.82% when the mass ratio of zeolite to PET was set to 2.0/1.0. The results indicate that ZSM-5 is able to facilitate the decomposition of carboxyl, aliphatic groups, and ether bonds in the primary products produced from the pyrolysis of PET. In addition, the deoxygenation effects on the waxy products have been significantly enhanced with the addition of zeolite based on the results of NMR.
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http://dx.doi.org/10.3390/polym12030705 | DOI Listing |
RSC Adv
September 2025
Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Saveetha University Chennai Tamil Nadu 602105 India.
A free radical polymerization approach was applied to synthesize different carboxymethyl cellulose-grafted poly(acrylamide) hydrogels (Hyd) composited with biochar, magnetic biochar, and magnetic biochar decorated with ZIF-67 to decontaminate methylene blue (MB) from water media. Biochar was obtained from walnut shells (WS) by a pyrolysis method, and magnetic biochar (WS/CoFeO) and biochar-decorated ZIF-67 (WS/CoFeO/ZIF-67) were prepared by chemical co-precipitation and hydrothermal methods, respectively. An increase in the amount of these particles by up to 10 wt% enhanced the removal performance.
View Article and Find Full Text PDFAnal Chem
September 2025
Department of Chemistry, The University of Akron, Akron, Ohio 44325, United States.
Tires are complex polymeric materials composed of rubber elastomers (both natural and synthetic), fillers, steel wire, textiles, and a range of antioxidant and curing systems. These constituents are distributed differently among the various tire parts, which are classified based on their function and proximity to the rim. This study presents a rapid and sensitive approach for the characterization of tire components using mild thermal desorption/pyrolysis (TDPy) coupled to direct analysis in real-time mass spectrometry (DART-MS).
View Article and Find Full Text PDFAnal Sci
September 2025
Frontier Laboratories Ltd., 4-16-20, Saikon, Koriyama, Fukushima, 963-8862, Japan.
Biomass-based polymers such as poly(lactic acid) (PLA) have attracted much attention, because they are renewable, biocompatible, and nontoxic to the environment and have been used in various fields such as biomedical, agricultural, and food packaging industries. However, one of the common drawbacks of PLA-based materials is their low glass transition temperature in the amorphous state, while adding phenylphosphonic acid zinc salt (PPA-Zn) as a nucleating agent was found to be a promising method to improve the physical property of PLA. On the other hand, degradation of PLA-based materials in the environment may cause the pollution from the metal of a nucleating agent in PLA and quantification of nucleating agents in polymers is of interest.
View Article and Find Full Text PDFChimia (Aarau)
August 2025
Department of Materials, ETH Zurich, CH-8093 Zurich.
Polymethacrylates, including poly(methyl methacrylate) (PMMA), are produced on a large scale for applications ranging from optics to construction, yet their end-of-life fate remains largely linear. Chemical recycling to regenerate the monomer (depolymerization) offers a promising route to circularity, but conventional methods such as pyrolysis rely on high-temperature random scission pathways that suffer from poor selectivity and undesirable side reactions. Recent advances have demonstrated that polymethacrylates synthesized by controlled radical polymerizations can undergo efficient depolymerization under milder conditions through reactivation of thermally labile chain-end functionalities.
View Article and Find Full Text PDFEnviron Sci Technol Lett
August 2025
Department of Chemistry and Chemical Biology, College of Science, Northeastern University, Boston, Massachusetts 02115, United States.
Although the relationship between plastics and their embedded small molecules has been previously hypothesized, direct and systematic evidence remains limited. Herein, we introduced an innovative approach to validate this relationship by screening specific small molecules as markers to decode plastic information. Given the mature techniques available for polymer identification, enabling subsequent validation, this study focused on screening polymer-specific small molecule markers.
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