摘要
聚对苯二甲酸乙二醇酯(PET)是一种广泛使用的高分子材料,但由于其不能自然降解,废旧PET对环境造成的压力越来越大,而对其进行解聚处理是一种环保有效的措施。介绍了PET的4种主要解聚方法,即醇解法、糖酵解法、水解法、胺解/氨解法的特点,以及PET解聚辅助方法的研究进展。醇解法以一元醇为降解剂使PET解聚成对苯二甲酸二甲酯(DMT),但回收成本和能耗较高;糖酵解法以二元醇为降解剂使PET解聚成苯二甲酸乙二醇酯(BHET),但BHET提纯困难;水解法以水为降解剂使PET解聚成对苯二甲酸(PTA),但酸性、碱性条件下需考虑设备腐蚀问题,而中性条件下PTA提纯困难;胺解/氨解法以乙二胺、乙醇胺等伯胺或氨水为降解剂使PET解聚,回收得到的解聚产物可用于合成高附加值产品,但反应时间较长、能耗较高。引入微波技术、超临界流体等辅助措施,或改进催化体系可缩短反应时间、降低能耗,得到高产率、高品质的回收产物。未来PET解聚体系的改进将体现在加热方式的转变,以及催化体系的改进上。
Poly(ethylene terephthalate)(PET)is a kind of widely used polymer material.However,the waste PET will bring more and more pressure to the environment because it cannot be degraded naturally.The depolymerization of PET is an effective environmental protection measure.The characteristics of four kinds of main PET depolymerization methods,namely alcoholysis,glycolysis,hydrolysis and amination/ammonolysis,were introduced,as was the research progress of assistant PET depolymerization methods.The alcoholysis method uses monohydric alcohol as a degradation agent to depolymerize PET into dimethyl terephthalate(DMT),but needs a high recycling cost and energy consumption.The glycolysis method uses glycol as a degradation agent to depolymerize PET into bis(2-hydroxyethyl)terephthalate(BHET),but it is difficult to purify BHET.The hydrolysis method uses water as a degrading agent to depolymerize PET into terephthalic acid(PTA),but the problem of equipment corrosion must be considered under acidic and alkaline conditions because PTA is difficult to be purified under neutral conditions.Amination/ammonolysis method uses primary amines such as ethylenediamine and ethanolamine or ammonia water as degradation agents to depolymerize PET,which requires long reaction time and high energy consumption although the recovered depolymerization products can be used to synthesize high value-added products.The introduction of microwave technology,supercritical fluid and other auxiliary measures,or the improvement of the catalytic system can shorten the reaction time,reduce energy consumption,and obtain high-yield high-quality recovered products.In the future,the improvement of PET depolymerization system will be reflected in the transformation of heating method and the improvement of catalytic system.
作者
邢玉静
严玉蓉
吴松平
曹泳琳
郭熙桃
马俊滨
马义忠
XING Yujing;YAN Yurong;WU Songping;CAO Yonglin;GUO Xitao;MA Junbin;MA Yizhong(School of Materials Science and Engineering,South China University of Technology,Guangzhou 510640;Guangdong Qiusheng Resources Co.,Ltd,Puning 515300)
出处
《合成纤维工业》
CAS
2020年第5期48-55,共8页
China Synthetic Fiber Industry
基金
国家重点研发计划项目(2018YFF0215500)。
关键词
聚对苯二甲酸乙二醇酯
解聚
催化剂
回收
微波技术
超临界流体
polyethylene terephthalate
depolymerization
catalyst
recovery
microwave technology
supercritical fluid