Tetrabromobisphenol-A (TBBA) is the most common brominated fire retardant. In this study, a TBBA containing paper laminated printed circuit board (PCB) prepared from novolac was pyrolysed by both TGA and in a quartz glass reactor between 40 and 1,000 degrees C. The products were online detected by MS. It was found that the PCB degraded in three steps. Step one (<270 degrees C) consisted of the evolution of water and CO(2) from the paper laminate. In the second step, between 270 and 370 degrees C, the fire retardant decomposed, releasing HBr and brominated aromatics. In the third step, at temperatures above 370 degrees C, the phenol resin decomposed and char was formed. Compared to pure TBBA, which mainly produces brominated phenols, the brominated products enclosed in the char released HBr during the last degradation step as well as during the second step. Most of the bromine left the resin in the form of HBr, with about 14% of the bromine being fixed in brominated aromatics and less than 2% remaining in the residue.
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http://dx.doi.org/10.1016/j.chemosphere.2007.11.033 | DOI Listing |
IDCases
December 2024
Department of Cardiac and Thoracic Surgery, The Military Hospital of Instruction of Tunis, Tunisia.
Hydatid disease is endemic in Tunisia. Whereas uncomplicated pulmonary hydatid cysts are easily diagnosed on radiological findings, complicated and atypical forms may be misdiagnosed and confused with other pulmonary lesions, mainly lung malignancies. We report a case of a 47-year-old woman, who presented with a 3-month history of hemoptysis.
View Article and Find Full Text PDFEcotoxicol Environ Saf
January 2025
School of Public Health, Xinjiang Medical University, Urumqi, China. Electronic address:
Objectives: Perchlorates, nitrates, and thiocyanates constitute environmental endocrine disruptors; however, health damage caused by absorption through the respiratory tract remains poorly studied. We investigated the effects of inhalation of these pollutants on thyroid function and structure and serum metabolomics in pregnant rats.
Methods: We established a Sprague-Dawley pregnant rat model exposed to perchlorate, nitrate, and thiocyanate at different gestational stages and compared maternal serum thyroid function levels, foetal development, thyroid morphology, and pathological changes between exposed and non-exposed groups at different concentrations.
Polymers (Basel)
December 2024
Collage of Mechanical & Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
The curing distortion is a critical determinant of the quality of integrally manufactured composite structures, playing a pivotal role in the design and fabrication of composite. This paper presents two simplified methods in predicting the curing distortion for large-scale composite aircraft structures manufactured through the autoclave process. Firstly, the refined finite element models of the two simplified methods were developed.
View Article and Find Full Text PDFMolecules
December 2024
Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China.
Ta/Re layered composite material is a high-temperature material composed of the refractory metal tantalum (Ta) as the matrix and high-melting-point, high-strength rhenium (Re) as the reinforcement layer. It holds significant potential for application in aerospace engine nozzles. Developing the Ta/Re potential function is crucial for understanding the diffusion behavior at the Ta/Re interface and elucidating the high-temperature strengthening and toughening mechanism of Ta/Re layered composites.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Department of Mechanical Engineering, North Carolina A & T State University,1601 E. Market Street, Greensboro, NC 27411, USA.
Damage in composite laminates evolves through complex interactions of different failure modes, influenced by load type, environment, and initial damage, such as from transverse impact. This paper investigates damage growth in cross-ply polymeric matrix laminates under tensile load, focusing on three primary failure modes: transverse matrix cracks, delaminations, and fiber breaks in the primary loadbearing 0-degree laminae. Acoustic emission (AE) techniques can monitor and quantify damage in real time, provided the signals from these failure modes can be distinguished.
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