Analysis of car shredder polymer waste with Raman mapping and chemometrics

Abstract

A novel evaluation method was developed for Raman microscopic quantitative characterization of polymer waste. Car shredder polymer waste was divided into different density fractions by magnetic density separation (MDS) technique, and each fraction was investigated by Raman mapping, which is capable of detecting the components being present even in low concentration. The only method available for evaluation of the mapping results was earlier to assign each pixel to a component visually and to count the number of different polymers on the Raman map. An automated method is proposed here for pixel classification, which helps to detect the different polymers present and enables rapid assignment of each pixel to the appropriate polymer. Six chemometric methods were tested to provide a basis for the pixel classification, among which multivariate curve resolution-alternating least squares (MCR-ALS) provided the best results. The MCR-ALS based pixel identification method was then used for the quantitative characterization of each waste density fraction, where it was found that the automated method yields accurate results in a very short time, as opposed to manual pixel counting method which may take hours of human work per dataset

Comparison of multivariate linear regression methods in micro-Raman spectrometric quantitative characterization

“…The vibrational techniques are widely used for exploration of quantitative information in many fields (e.g. in food industry, plastic industry or art) . In the pharmaceutical industry especially the chemical imaging (CI) is gaining interest currently due to its versatile applicability in pharmaceutical processes .…”

Upgrading of recycled polypropylene by preparing flame retarded layered composite

“…After a comprehensive component analysis (Fourier transform infrared spectroscopy -FTIR, Raman, thermogravimetry -TG, differential scanning calorimetry -DSC) [17], it was found that below the density of 900 kg/m 3 the main polymer component is polypropylene (>#78 %), melt flow rate (MFR) (190°C, 2.16 kg) 2.14 g/10 min and its inorganic filler residue content (determined by heating under mass loss calorimeter with heating wire of 900°C, which means approx. 650°C on the surface of the samples) is lower than 0.75 mass%, containing mainly talc, calcium-carbonate and short glass fibre.…”

Quantitative Evaluation of Drug Distribution in Tablets of Various Structures via Raman Mapping

“…The vibrational spectroscopy such as Raman or NIR is potentially useful to provide qualitative [2] and quantitative [3][4][5][6] information about the studied substances. In addition, the application of imaging procedure allows us to obtain a number of local, pixel-like data in lateral or even vertical directions.…”