Compounding and Mixing Methodology for Good Performance of EPDM in Tire Sidewalls

Shi

Environ. Sci. Technol. Lett.

et al. 2021

148

The substituted p-phenylenediamines (PPDs) represent a suite of effective antioxidants broadly applied in rubber industries. However, knowledge of their environmental occurrences and fate remains extremely limited. Herein, we explored the occurrence of six major PPD antioxidants and one newly defined transformation product in dust particles from different environments, including roads, underground parking lots, vehicles, and houses. The majority of the PPDs exhibited ubiquitous occurrence in these environments. Median concentrations of total PPDs were determined to be 226 ng/g in road dust, 232 ng/g in parking lot dust, and 156 ng/g in vehicle dust, orders of magnitude greater than those in house dust (14.0 ng/g). Different composition profiles of PPDs were also found between house dust and vehicle-related dust, likely indicating the influence of vehicle tires or other rubber products. In addition, a major ozonation product of N-(1,3-dimethylbutyl)-N′-phenyl-1,4-phenylenediamine (6PPD), 6PPD-qunione, was also identified in dust with levels (median range of 32.2–80.9 ng/g) comparable to that of 6PPD except in house dust. To the best of our knowledge, this is the first systematic investigation of the occurrence of major PPD antioxidants and 6PPD-qunione in various dust matrices. Our findings would attract attention to their environmental fate and ecological and human health risks.

Section: Resultsmentioning

confidence: 99%

Occurrence of Substituted p-Phenylenediamine Antioxidants in Dusts

Shi

Environ. Sci. Technol. Lett.

et al. 2021

148

“…The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.est.2c07652. Physicochemical properties as well as overall persistence and long-range transport potential (Pov, CTD, and TE) of seven PPDs and four PPD-Qs (Table S1); optimized ESI (+)-MS/MS parameters (Table S2); summarized QA/QC results (Table S3); detailed concentration data (Table S4); Spearman's correlation analysis (Table S5); MRM chromatograms and MS 2…”

Section: * Sı Supporting Informationmentioning

confidence: 99%

“…p -Phenylenediamines (PPDs) are an important class of synthetic antioxidants that are used as additives in rubber-related products, mostly in rubber tires. , Among the globally used PPDs, N -(1,3-dimethylbutyl)- N ′-phenyl- p -phenylenediamine (6PPD) is the most frequently used tire antioxidant and has been listed as a high production volume (HPV) chemical by the Organization for Economic Co-operation and Development (OECD) . In China, the current annual production of 6PPD alone is 200,000 tons, accounting for approximately 54% of the total production of all current-use rubber antioxidants .…”

Section: Introductionmentioning

confidence: 99%

Widespread Occurrence and Transport of p-Phenylenediamines and Their Quinones in Sediments across Urban Rivers, Estuaries, Coasts, and Deep-Sea Regions

Zeng

Sun

et al. 2023

Environ. Sci. Technol.

p-Phenylenediamines (PPDs) are widely used as antioxidants in tire rubber, and their derived quinone transformation products (PPD-Qs) may pose a threat to marine ecosystems. A compelling example is N-(1,3-dimethylbutyl)-N′phenyl-p-phenylenediamine (6PPD)-derived quinone, called 6PPD-Q, as the causal toxicant for stormwater-linked acute mortality toward coho salmon. However, the knowledge of the cooccurrences of PPDs and PPD-Qs and their transport from freshwater to oceanic waterbodies on a large geographical scale remains unknown. Herein, we performed the first large-scale survey of these chemicals in sediments across urban rivers, estuaries, coasts, and deep-sea regions. Our results demonstrated that seven PPDs and four PPD-Qs are ubiquitously present in riverine, estuarine, and coastal sediments, and most of them also occur in deep-sea sediments. The most dominant chemicals of concern were identified as 6PPD and 6PPD-Q. Total sedimentary concentrations of PPDs and PPD-Qs presented a clear spatial trend with decreasing levels from urban rivers (medians: 39.7 and 15.2 ng/g) to estuaries (14.0 and 5.85 ng/g) and then toward coasts (9.47 and 2.97 ng/g) and deep-sea regions (5.24 and 3.96 ng/g). Interestingly, spatial variation in the ratios of 6PPD to 6PPD-Q (R 6PPD/6PPD-Q ) also presented a clear decreasing trend. Our field measurements implied that riverine outflows of PPDs and PPD-Qs may be an important route to transport these tire rubber-derived chemicals to coastal and open oceans.

“…Substituted para -phenylenediamines (PPDs), as a class of anthropogenic antioxidants, have been largely produced and applied in the rubber industry due to their capability for the protection of rubber materials against flex cracking, heat degradation, and ozone cracking. 1 However, massive production and consumption of these PPD antioxidants have caused increasing concern regarding their emissions and potential influence on the aquatic and terrestrial ecosystems. Emerged evidence indicated that these chemicals can be ubiquitously detected in receiving waters, 2 , 3 dusts, 4 , 5 sediments, 6 and air particles.…”

Section: Introductionmentioning

confidence: 99%

“…9,10 In addition, N-isopropyl-m′-phenyl-p-phenylenediamine (IPPD) was defined as predominantly occupational allergens, causing allergic contact dermatitis through direct contact with industrial rubber. 11 A test report from the U.S. EPA has illustrated the acute toxicity of N,N′-bis (1,4-dimethylpentyl)-p-phenylenediamine (77PD) to rats through inhalation with a LC 50 of 400 mg/m 3 . 12 In addition to PPDs, the environmental emissions and acute toxicity of their derived quinones (PPD-Qs) have attracted great attention lately.…”

Section: ■ Introductionmentioning

confidence: 99%

Beyond Substituted p-Phenylenediamine Antioxidants: Prevalence of Their Quinone Derivatives in PM_2.5

Wang

Cao

Zhang

et al. 2022

Environ. Sci. Technol.

Substituted para -phenylenediamine (PPD) antioxidants have been extensively used to retard oxidative degradation of tire rubber and were found to pervade multiple environmental compartments. However, there is a paucity of research on the environmental occurrences of their transformation products. In this study, we revealed the co-occurrence of six PPD-derived quinones (PPD-Qs) along with eight PPDs in fine particulate matter (PM 2.5 ) from two Chinese megacities, in which N , N ′-bis(1,4-dimethylpentyl)- p -phenylenediamine quinone (77PD-Q) was identified and quantified for the first time. Prevalent occurrences of these emerging PPD-Qs were found in Taiyuan (5.59–8480 pg/m 3 ) and Guangzhou (3.61–4490 pg/m 3 ). Significantly higher levels of PPDs/PPD-Qs were observed at a roadside site, implying the possible contribution of vehicle emissions. Correlation analysis implied potential consistencies in the fate of these PPD-Qs and suggested that most of them were originated from the transformation of their parent PPDs. For different subpopulation groups under different exposure scenarios, the estimated daily intakes of PPD-Qs (0.16–1.25 ng kg bw –1 day –1 ) were comparable to those of their parent PPDs (0.19–1.41 ng kg bw –1 day –1 ), suggesting an important but overlooked exposure caused by novel PPD-Qs. Given the prolonged exposure of these antioxidants and their quinone derivatives to traffic-relevant occupations, further investigations on their toxicological and epidemiological effects are necessary.