Mechanical recycling of PET containing mixtures of phosphorus flame retardants  

作　　者：Jiuke Chen Sithiprumnea Dul Sandro Lehner Milijana Jovic Sabyasachi Gaan Manfred Heuberger Rudolf Hufenus Ali Gooneie 

机构地区：[1]Empa,Swiss Federal Laboratories for Materials Science and Technology,Laboratory of Advanced Fibers,St.Gallen,Switzerland [2]ETH Zurich,Department of Materials,Switzerland [3]Circular Plastics,Department of Circular Chemical Engineering,Faculty of Science and Engineering,Maastricht University,Urmonderbaan 22,6162 AL Geleen,The Netherlands

出　　处：《Journal of Materials Science & Technology》2024年第27期167-179,共13页材料科学技术(英文版)

摘　　要：Flame-retarded polymers,such as polyester textiles and sheets,are attracting attention with regard to their sustainability.Mechanical recycling is currently the most frequently used technique for improving the circularity of plastics.However,one complication of mechanical recycling is associated with the(still)inevitable mixtures of polymers and additives,which can influence material stability and significantly de-teriorate the mechanical properties of recycled products.In this study,we aim to specifically investigate the interactions between mixtures of phosphorus flame retardants(FRs)in polyethylene terephthalate(PET)and evaluate their potential role in the mechanical recycling of melt-spun fibers.Two highly rel-evant commercial FRs,namely a DOPO-derivative(DOPO-PEPA or DP)and Aflammit PCO 900(AF),are added to PET compounds as additives using a melt compounder.The melt stability of PET/FR compounds over extended processing time is assessed by chemical,thermal,and rheological measurements.DP shows a molecular lubrication effect,lowering the melt viscosity of PET,while AF promotes chemical changes(i.e.,chain branching/crosslinking).Interestingly,a PET compound containing hybrid mixtures of DP/AF 20/80(wt.%/wt.%)shows the most stable behavior at high temperatures under both nitrogen and air at-mospheres,thus showing a synergistic effect.Most importantly,in a recycling scenario,the stabilization effect persists at diluted concentrations below the typical FR contents in PET.Multiple extrusion cycles are used to assess the repeated processing behavior of the compounds,and the mechanical properties and fire behavior of melt-spun fibers are compared before and after recycling.The results reveal that DP can maintain the mechanical performance of recycled PET/FR fibers,even if it is mixed(contaminated)with AF.

关 键 词：PET Mechanical recycling Melt spinning Phosphorus flame retardant 

分 类 号：TG1[金属学及工艺—金属学]