Study On Identification Technology Of Recycled Plastics

Recycled plastic comes from waste plastic, contained sorts of harmful substances. These substances may originate from the residues of packing contents, the additives which were used in production or the degradation products of polymers or additives. Hence, plastic packaging materials that directly don't contact with drugs and foods must be made from virgin materials rather than recycled materials. However, there are neither corresponding regulatory policies about recycled plastics, nor specific authoritative methods to identify the recycled plastics. At present appearance inspection is frequently used to detect the recycled plastics, but it is so difficult to accomplish this task, especially for the recycled plastics similar to virgin plastics in color. In this thesis, a series of analytical methods have been developed to identify recycled plastics in contrast with virgin plastics.First, the definition of recycled plastics, waste plastics and virgin plastics has been discussed. Secondly, five common kinds of virgin materials (PE, PP, ABS, PVC and TPU) and their recycled plastic resins have been characterized in this paper. Using infrared spectrometry and thermal analysis (DSC and TG) methods, many kinds of virgin resins and recycled plastic resins have been contrastively analyzed, a series of fingerprints spectra of virgin resins and recycled resins have been established. In order to characterize the components in PVC recycled plastics, TGA-IR and GC-MS analyses have been utilized, in addition to conventional methods, such as IR spectroscopy.