March 13, 2025 – Unraveling the composition of mixed plastics is a complex and intricate task that marries a variety of separation techniques with advanced analytical instruments. Through the expert reverse engineering by technicians, both qualitative and quantitative analyses of unknown sample components are achieved. Among the myriad of analytical methods, Infrared Spectroscopy (IR) stands out as a favorite. By capturing the infrared spectral signatures of plastic samples using an infrared spectrometer and comparing them against known standards or libraries, this technique swiftly and non-destructively identifies the plastic components within the sample, accommodating various forms of plastic materials.
Another potent analytical tool is Thermogravimetric Analysis coupled with Gas Chromatography-Mass Spectrometry (TGA-GC/MS). This method involves thermally decomposing plastic samples at high temperatures to release volatile compounds, which are then meticulously analyzed and identified using GC-MS technology. Particularly suitable for complex plastic mixtures, TGA-GC/MS provides comprehensive component information.
According to AsiaMB, Liquid Chromatography (LC) also plays a pivotal role in the analysis of mixed plastic components. By dissolving plastic samples in appropriate solvents and utilizing LC technology, this method effectively separates and analyzes the various constituents in the sample. It is especially advantageous for plastic components that are difficult to volatilize or are unstable in gas chromatography.
Furthermore, Nuclear Magnetic Resonance (NMR) Spectroscopy is a significant analytical technique. Employing an NMR spectrometer to test plastic samples, it accurately determines the components by deeply interpreting the NMR spectra of the samples. Elemental Analysis, on the other hand, measures the content of various elements in plastic samples using elemental analysis instruments, thereby inferring the possible plastic components present. This method is particularly useful for confirming the presence of specific elements in plastics.
The techniques for analyzing mixed plastic components find widespread application in the testing of various plastic products, including food packaging, beverage bottles, plastic containers, plastic bags, plastic toys, electronic product casings, household items, and plastic fibers in clothing. They provide robust support for quality control and product development in the plastic industry.