Pyrolysis of used tires is a promising method for recovering valuable chemicals. However, the conventional high-temperature pyrolysis of natural rubber (polyisoprene)-based tires suffers from a low-selective isoprene recovery, heavy carbon black (CB) damage, and coke formation on the CB. In this paper, we report on characteristics of the low-temperature pyrolysis of CB-containing polyisoprene-based tire rubber that is vulcanized with sulfur. The low-temperature pyrolysis of the tire rubber cleaves the main chain and cross-linking bonds, which allows for the recovery of low-molecular-weight tire rubbers, tire rubber dissolution into the solvent, and CB isolation from the rubber matrix. The maximum liquid rubber recovery rate was 76.7% after 1 h of heating at 282 °C. In addition, the molecular weight of the thermally treated rubber substantially decreased from 340,000 to approximately 20,000 after 1 h of heating at 282 °C. Furthermore, the maximum isoprene skeleton retention rate of the recovered rubber was 83% at 267 °C after 1 h of heating. The remaining rubber matrix on the recovered CB surface was nearly eliminated at temperatures above 320 °C. In conclusion, we believe that the low-temperature pyrolysis of tire rubber is a promising pretreatment method for recovering CB without thermal damage and reducing the molecular weight of tire rubber, which will improve the recovery of isoprene.
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http://dx.doi.org/10.1021/acsomega.4c09456 | DOI Listing |
Water Environ Res
March 2025
Environmental Science Center, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Uncertainties in the quantification of microplastics in various products arise from the applied pretreatment processes. Road dust, a significant source of microplastics, requires precise quantification methods to ensure accuracy. In this study, we examined the impact of pretreatment processes on the accuracy of microplastic quantification in road dust, specifically focusing on tire rubber particles.
View Article and Find Full Text PDFACS Omega
March 2025
Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
Pyrolysis of used tires is a promising method for recovering valuable chemicals. However, the conventional high-temperature pyrolysis of natural rubber (polyisoprene)-based tires suffers from a low-selective isoprene recovery, heavy carbon black (CB) damage, and coke formation on the CB. In this paper, we report on characteristics of the low-temperature pyrolysis of CB-containing polyisoprene-based tire rubber that is vulcanized with sulfur.
View Article and Find Full Text PDFWaste Manag
March 2025
Specialized Center of Rubber and Polymer Materials in Agriculture and Industry (RPM), Department of Materials Science, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; Hub of Talents in Natural Rubber, National Research Council of Thailand (NRCT), Bangkok 10900, Thailand. Electronic address:
This study explores the use of fly ash (FA), a waste material, to partially replace zinc oxide (ZnO) as an activator in tire tread processing. Reducing ZnO addresses its environmental risks, particularly the impact of ZnO leakage into aquatic ecosystems throughout the tire's life cycle. The FA was altered by including rubber compound with and without ZnO, using ZnO-to-FA ratios of 3:0 (control), 2:1, 1:2, 0:3, or 0:5 parts per hundred of rubber (phr).
View Article and Find Full Text PDFComp Biochem Physiol C Toxicol Pharmacol
March 2025
Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Global Institute for Water Security, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
6PPD-quinone, an environmental oxidation product of the rubber tire antioxidant 6PPD, has recently gained recognition as a chemical of concern. Frequently detected in road runoff and surface waters, studies have reported this compound to cause acute lethality in several salmonid species at extremely low concentrations, including lake trout (Salvelinus namaycush; 24-h LC = 0.51 μg/L).
View Article and Find Full Text PDFJ Chem Phys
February 2025
The Yokohama Rubber Company, 2-1 Oiwake, Hiratsuka, Kanagawa 254-8601, Japan.
We study the wear rate (mass loss per unit sliding distance) of a tire tread rubber compound sliding on concrete paver surfaces under dry and wet conditions, at different nominal contact pressures of σ0 = 0.12, 0.29, and 0.
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