Study On The Identification Of Recycled Plastics

Plastics have been used for a variety of applications in pharmaceutical package such as polyolefin infusion bottles, non-polyvinylchloride multilayer polymer infusion bags, PP bottles for oral drugs due to their low density, high tenacity, easy manufacturing and relatively low cost. Recycled plastics investigated in this thesis are defined as new articles processed from postconsumer plastics waste. In order to ensure drug safety, plastic packaging containers that directly contact with drugs should be made of virgin materials rather than postconsumer recycled materials. The harmful or deleterious substances in postconsumer recycled plastic materials may cause serious damage to health when they contaminate the drug products. However, compared with virgin plastics, postconsumer recycled plastics made from plastic wastes are usually cheaper so that it is considerably attractive to adulterate high-value products with less expensive recycled resins.There is no specific authoritative method to detect the adulteration, and only appearance inspection is frequently used to detect the adulteration of plastic products, but it is difficult to accomplish this task, especially when the postconsumer recycled plastic is quite similar to virgin plastic in color. To ensure the safety of drugs, a series of analytical methods were developed to identify pharmaceutical plastic packaging containers adulterated with postconsumer recycled plastics in this paper.The characteristic quality properties including the degree of mixing contaminants, the degree of oxidation and degradation, and the presence of low molecular weight compounds were evaluated to distinguish the virgin plastics and the recycled plastics. The analytical methods of NIR, thermal analysis, IR, and X-Ray fluorescence spectrometry were applied for identification and could be used by two steps. In the first step, near-infrared spectroscopy coupled with conformity test was applied to screen the adulteration of pharmaceutical plastic packaging containers with postconsumer recycled plastics. Samples passed the NIR models were released, and samples rejected by the NIR models were taken back to labs for further verification. In the second step, technologies of thermal analysis, infrared spectroscopy, X-Ray fluorescence spectrometry and YBB legal measuring methods were applied to confirm whether the suspicious samples were adulterated. These methods for verification use complemented the YBB legal measuring methods and verified mutually.All spiked PP bottles with the minimum spiking level of20%and HDPE bottles with the minimum spiking level of10%were identified correctly by these analytical methods, and an unqualified sample in practice was identified by these analytical methods. Therefore, the developed methods are feasible to identify both the modeled adulterants and the practical adulteration derived from other adulterants. These strategies represent promising analytical methods for identifying the adulteration of pharmaceutical plastic packaging containers with postconsumer recycled plastics.The methods of NIR, DSC, and X-Ray fluorescence spectrometry were first applied to identify the PP adulterated bottles and HDPE adulterated bottles. The results have been published in the journal of Analytic Chimica Anta and have applid for a patent about the rapid test by NIR method.