Debromination of high impact polystyrene for polymer recycle

聚苯乙烯（PS）是最丰富的热塑性聚合物之一，2016年全球需求量为640万公吨（Mt），每年增长2.3%。聚苯乙烯的应用范围从包装到电子设备（包括通用高抗冲聚苯乙烯-HIPS）到不可生物降解的包装。溴化阻燃剂（BFR）被添加到电子产品中的HIPS中以减少火灾危险，但其环境毒性大于传统的PS，因为它具有生物累积性。2016年，全球废弃电子电气设备（WEBs）达到4470万吨，到2021年将增长到5220万吨。中国禁止进口塑料废物增加了加拿大必须处理的废塑料数量，含有Br-HIPS的废塑料数量将在未来许多年内进入回收流程。因此，技术发展是必要的。找到溴-高抗冲聚苯乙烯脱溴的方法将减少环境负担，提高高抗冲聚苯乙烯的可回收性，防止其进入垃圾填埋场和露天垃圾场，以不可持续的方式处理，同时满足对原始高抗冲聚苯乙烯的需求。* HIPS脱溴技术包括超临界水和热解，可降解HIPS，消除回收的可能性。Lavergne集团抓住了这一机会，创造了一种处理这种废物的商业模式。他们与蒙特利尔理工大学接洽，设想并设计一种可扩展的程序，从HIPS中去除溴，以回收他们在魁北克库存的数千吨（甚至更多）Br-HIPS。我们已经确定并测试了使用溶剂处理对溴-高抗冲聚苯乙烯进行脱溴的技术，该技术可防止聚苯乙烯降解，同时保持其在常规生产线中的可回收性。** 精确测量液相和固相中Br的能力对于该计划的成功至关重要。 然而，很少有分析技术能够精确测量溴。 蒙特利尔地区目前没有任何设施。X射线荧光（XRF）是一种定性和定量的工具，被广泛用于各种含有溴化阻燃剂的报废塑料。事实上，这是符合欧洲联盟（欧盟）和联合国环境规划署（环境署）的分析技术。XRF是一种非破坏性的技术，可以定量从钠到铀的元素，能够在不到30分钟的时间内确定从ppm到100%的浓度，提供可靠的结果，维护成本低。

Polystyrene (PS) ranks among the most abundant thermoplastic polymers with a world demand of 6.4 million metric tons (Mt) in 2016, and it grows 2.3 % every year. PS applications range from packaging to electronic devices (comprising general-purpose high-impact polystyrene -HIPS) to non-biodegradable packaging. Brominated flame retardants (BFR) are added to HIPS in electronics to reduce fire hazard, but its environmental toxicity is greater than traditional PS, since it bioaccumulates. The global waste electric and electronic equipment (WEEE) reached 44.7 million Mt in 2016 and will grow to 52.2 million Mt by 2021. The Chinese ban of plastic waste import has increased the amount of WEEE Canada will have to deal with and the amount of WEEE containing Br-HIPS will reach the recycling stream for many years to come. Technology development is therefore a necessity. Finding a methodology to debrominate Br-HIPS will reduce the environmental burden and increase the recyclability of HIPS, preventing it from reaching landfills and open dumps, treated in an unsustainable manner, while at the same time fulfilling the need for virgin HIPS. ***Techniques to debrominate HIPS include supercritical water and pyrolysis, which degrade HIPS eliminating the possibility of recovering it. Lavergne Group has seized this opportunity and has created a business model to treat this waste. They approached Polytechnique Montréal to conceive and design a scalable procedure to remove bromine from HIPS to recycle the several kilotons (and more) of Br-HIPS that they have in stock in Quebec. We have already identified and tested technology to debrominate Br-HIPS using a solvent-treatment that prevents the degradation of PS, while maintaining its recyclability in regular process lines. ******The ability to measure precisely Br in the liquid phase and solids phase is critical to the success of this program. However, few analytical techniques are capable of measuring bromine precisely. No facilities are available in the Montreal region currently. X-ray fluorescence (XRF) is the qualitative and quantitative tool universally adopted for a variety of end-of-life plastics containing brominated flame retardants. Indeed, it is the analytic technique that is in compliance with European Union (EU) and United Nations Environment Programme (UNEP). XRF is a non-destructive technique to quantify elements from sodium to uranium, able to determine concentrations from the ppm to 100% in less than 30 min, giving reliable results and with low maintenance cost.**