Polymer waste, analysis

Dutch law has indicated NAA as the technique of choice for the analysis of polymer waste (recycling). INAA has been recommended as the analysis technique for the determination of cadmium in industrial products. 

This book is a collection of invited, reviewed, contributed and poster papers presented at the conference. The typical presentation is multidisciplinary, containing a blend of chemistry, physics, materials processing and technology applications. The result is a comprehensive overview of polymer-related topics, including innovative synthetic techniques, electronic properties, processing, device applications, material recovery, and waste analysis. Both review and research papers are included. The review papers should assist in the cross-fertilization of different areas, while the research papers will serve as useful reference materials summarizing the current status of individual topics and projecting future directions. 

Automatic polymer waste sorting plants based on NIR identification are operative (c/r. Chp. 1.2.2). For identification and sorting of carpets a portable NIR spectroscopic system - CarPID - was developed [139]. Other reported NIRS applications are to be found in the quantitative analysis of copolymers or blends the near-IR range allows for accurately monitoring of the monomer ratio and residual monomer content. Ikeda [140] used near-IR spec-trochemical analysis in controlled manufacture of polyester plasticisers. Jones et al. [141] similarly described the use of NIR analysis for controlling plasticiser ester formation the esterification of phthalic anhydride by isodecyl alcohol was exemplified. 

In contrast to Raman and IR spectroscopy, only few chemical functionalities (CH, OH, and NH) have a signature in the NIR spectra. Thus, the use of NIR spectra as stmctural interpretation tool is strongly limited. For raw material control or discrimination purposes, however, such as the sorting of polymer waste into a selected numher of commodities (e.g., polyethylene, polypropylene, polystyrene, poly(ethylene ter-ephthalate) (PET), and poly(vinyl chloride) (Figure 51), qualitative chemometric evaluation techniques (such as principal component analysis (PCA)) can he applied. ... 

The purpose of the study was to determine the optimum conditions of operation of pyrolysis equipment by the combined solution of equations relating to the technological and economic analysis of the process. The material considered was poly(methyl methacrylate) one of the most popular types of plastic waste. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. 

Identification and sorting of plastics in waste materials were reviewed [19,31]. Garbassi [32] has stressed the important role played by polymer analysis and characterisation in plastics recycling. 

Contaminants in recycled plastic packaging waste (HDPE, PP) were identified by MAE followed by GC-MS analysis [290]. Fragrance and flavour constituents from first usage were detected. Recycled material also contained aliphatic hydrocarbons, branched alkanes and alkenes, which are also found in virgin resins at similar concentration levels. Moreover, aromatic hydrocarbons, probably derived from additives, were found. Postconsumer PET was also analysed by Soxhlet extraction and GC-MS most of the extracted compounds (30) were thermally degraded products of additives and polymers, whereas only a few derived from the original contents... 

Metal derivatives (Ti, Zn, Cd, Sn, Sb, Pb) and bromine from additives in recycled thermoplasts from consumer electronic waste were determined by dissolving the samples in an organic solvent, followed by TXRF analysis [56], The procedure proved considerably less time-consuming than conventional digestion of the polymer matrix. Results were validated independently by INAA. 

Several existing protocols require a solvent (acetone, methanol, isopropanol) rinse as part of equipment decontamination for VOC sampling and 1 10 percent hydrochloric or nitric acid rinse for metal analysis sampling (DOE, 1996 USACE, 1994). These practices, successful as they may be in removing trace level contaminants, create more problems than they are worth. Organic solvents are absorbed by the polymer materials used in sampling equipment construction and appear as interferences in the VOC analysis. Acid destroys the metal surfaces of soil sampling equipment and induces corrosion. The use of solvents and acids is a safety issue and it also creates additional waste streams for disposal. 

Some general applications of TG-FTIR are evolved gas analysis, identification of polymeric materials, additive analysis, determination of residual solvents, degradation of polymers, sulphur components from oil shale and rubber, contaminants in catalysts, hydrocarbons in source rock, nitrogen species from waste oil, aldehydes in wood and lignins, nicotine in tobacco and related products, moisture in pharmaceuticals, characterisation of minerals and coal, determination of kinetic parameters and solid fuel analysis. 

The most creative application of the secondary cathode approach was described by Schelles and Van Grieken [24], who investigated its ability to determine the elemental constituents of polymeric materials. Mass spectrometric analysis has almost exclusively been directed at the determination of molecular weights and disparity characteristics secondary ion mass spectrometry (SIMS) [53,54] and matrix assisted laser desorption ionization (MALDI) [55,56] have carried the major share of the workload. Growing concerns over the fate of polymeric materials in the environment and the leaching of heavy metals into ground waters have necessitated the development of methods that permit the elemental analysis of bulk polymers. In addition, the use of polymers as immobilization media for waste remediation is also pressing these developments. 

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