(163bs) Recyclability of Flame Retardant Polycarbonate: Comparison of Non-Halogenated to Halogenated Flame Retardants

Plastic waste from Electrical and Electronic Equipment (WEEE) is an increasing problem. Plastics, such as, HIPS, ABS and polycarbonate (PC) must often be disposed of as hazardous waste because of contact with heavy metals in WEEE. Consequently, it is desirable to separate and recycle these plastics. The main focus of this presentation will be on polycarbonate. One of the concerns here is keeping or enhancing the flame retardant properties of PC so that the material can be reused in equipment housings. Using data on potassium diphenylsulfone sulfonate (KSS) as a flame retardant, it is shown that the flame retardancy of recycled PC can be enhanced. One major advantage of using KSS is that it is non-halogenated, playing an important role as the government eliminates the use of halogenated flame retardants because of potential unhealthy environmental effects. In this study, a PC containing KSS and one containing a halogenated FR are put through a recycling process -- drying, extrusion, pelletizing, drying, injection molding, and granulating. This process is repeated up to eight times. Mechanical results were assessed by Izod impact and tensile tests. Thermogravimetric analysis and capillary rheometry were also performed. Results show that the non-halogenated flame retardant polycarbonate holds up just as well as the halogenated flame retardant polycarbonate. It is concluded that potassium diphenylsulfone sulfonate is likely to be an excellent non-halogenated flame retardant for recycled polycarbonate.