Key Laboratory of Separation Science for Analytical Chemistry , Dalian Institute of Chemical Physics , Chinese Academy of Sciences, Dalian , 116023 , China.
University of Chinese Academy of Sciences , Beijing 100049 , China.
Environ Sci Technol. 2019 Jan 2;53(1):185-193. doi: 10.1021/acs.est.8b05483. Epub 2018 Dec 18.
Thermal scenarios inevitably occur during the lifecycle of engineering plastics laden with brominated flame retardants (BFRs). However, little information on the fate of embedded BFRs during the thermal processes is available. In this study, we measured the release and transformation of a typical BFR, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), during the thermal treatment of acrylonitrile butadiene styrene (ABS) plastics. The possible thermal scenarios were simulated by varying the heating temperature and atmosphere. The maximum release rate of BTBPE was observed at 350 °C. A release kinetic model was developed to explore the mechanism of BTBPE release while heating ABS. Material-phase diffusion was found to be the rate-determining step during release. According to the developed release model, it was estimated that 0.04-0.17% of embedded BTBPE could be released to air during the industrial processing of ABS plastics. When the heating temperature was ≥350 °C, approximately 15-56% of embedded BTBPE decomposed to bromophenols (BPs) and 1,3,5-tribromo-2-(vinyloxy) benzene (TBVOB), and the decomposition followed a first-order kinetics at 350 °C. Polybrominated dibenzo- p-dioxins and dibenzofurans (PBDD/Fs) were also significantly formed at ≥350 °C from BPs and TBVOB via a precursor mechanism. A higher temperature (≥450 °C) was favorable for the formation of PBDFs.
在含有溴系阻燃剂 (BFRs) 的工程塑料的生命周期中，不可避免地会出现热情况。然而，关于嵌入 BFRs 在热过程中的命运的信息很少。在这项研究中，我们测量了典型 BFR 1,2-双（2,4,6-三溴苯氧基）乙烷 (BTBPE) 在丙烯腈丁二烯苯乙烯 (ABS) 塑料热处理过程中的释放和转化。通过改变加热温度和气氛来模拟可能的热情况。在 350°C 时观察到 BTBPE 的最大释放速率。开发了一个释放动力学模型来探索加热 ABS 时 BTBPE 释放的机制。发现材料相扩散是释放过程中的速率决定步骤。根据开发的释放模型，估计在 ABS 塑料的工业加工过程中，约有 0.04-0.17%的嵌入 BTBPE 可能会释放到空气中。当加热温度≥350°C 时，约有 15-56%的嵌入 BTBPE 分解为溴酚 (BPs) 和 1,3,5-三溴-2-(乙烯氧基)苯 (TBVOB)，分解在 350°C 时遵循一级动力学。通过前体机制，BPs 和 TBVOB 还会在≥350°C 时显著形成多溴二苯并-对-二恶英和二苯并呋喃 (PBDD/Fs)。较高的温度（≥450°C）有利于 PBDFs 的形成。
