Flame Retardant,Toughening And Strengthening Modification Of Recycled PET Flakes

As an excellent engineering plastics,polyethylene terephthalate(PET)is widely used in films,fibers,bottles,electrical appliances,etc.In particular,with the development of the food and beverage industry,PET plastic bottles have become the most important packaging materials for mineral water,juices and tea beverages.Because PET plastic bottles are mostly disposable products,they will cause serious white pollution after discarding,and recycled PET bottles can be used as new raw material resources to ease the shortage of PET raw materials.However,the recycled PET has poor mechanical properties and is easily hydrolyzed.Moreover,the recycled PET bottles are mostly used for spinning to make fibers,which require high flame retardancy.For this reason,the pursuit of effective methods to modify recycled PET(rPET),making rPET highly flame-retardant and high mechanical properties is the key to expanding the use of rPET.Therefore,in this paper,flame-retardant PET composite with excellent flame retardant and mechanical properties were prepared by a twin-screw extruder using a melt-blending method.The specific methods are as follows:1.Using four environmentally friendly halogen-free phosphorus flame retardants and rPET for melt blending,and then testing the flame retardancy of the composite.Among them,the flame retardant EPFR-100A has the best flame retardant effect,and the limiting oxygen index(LOI)of the flame retardant composite added with 15wt%is 27.8%.The flame retardant was surface-treated with different ratios of titanate coupling agent,and the best effect of modifying the flame retardant was 4wt%of titanate coupling agent.2.The modification of the composite is performed with a maleic anhydride modified POE for toughening modification.When the added POE content was 5wt%,the mechanical properties of the composite were the best.3.Halloysite nanotubes(HNTs)were added into rPET composite and its properties were studied.After adding HNTs,the mechanical properties of the composite decreased but the flame retardancy was enhanced,and the LOI of the composite reached 29.4%.Moreover,the melting point and crystallization temperature of the composite are reduced,which can reduce the pr~oessing temperature of the composite.4.Glass fiber(GF)was added into the composite to strengthen the composite.The mechanical properties of the composite are best when the proportion of GF is 30wt%.The tensile strength,flexural strength and impact strength of the composite were 21.5 MPa,25.6MPa,and 3.1 kJ/m~2.The LOI of the composite was 29.7%.