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Raman spectroscopy is used for material characterization by analyzing molecular or crystal symmetrical vibrations and rotations that are excited by a laser, and exhibit vibrations specific to the molecular bonds and crystal arrangements in the molecules. Raman technology is a valuable tool in distinguishing different polymorphs. Examples of portable Raman spectroscopy for identification of polymorphs and in monitoring the polymorphic transiton of citric acid and its hydrated form are presented.

Research laboratories must expand their capabilities to routinely analyze candidate microplastics from environmental samples to determine their origin and help predict biological impacts. Spectroscopic techniques are well suited to polymer identification. Laboratory Raman spectroscopy is an alternative to confocal Raman microscopes and Fourier transform infrared (FTIR) microscopes for quick identification of polymer materials. Raman microscopy was used to identify very small microplastic particles in this Application Note.

Quantitation of the functionalization of a water-soluble polymer was achieved using a portable Raman spectrometer. The Raman spectrum provides strong, unique bands for both the initial and fully reacted polymer. This enables development of a simple, robust quantitative analysis of the percent polymer functionalization. This method is now routinely used in a manufacturing plant's quality control laboratory.

This Application Note describes the determination of copolymer levels in polyethylene (PE) and polyvinylacetate (PVA) pellets using NIRS. The determination of the composition of the polymer blends takes less than 30 seconds and requires no sample preparation. The second derivative spectra are analyzed by means of the linear least-squares regression method.

This Application Note shows that NIR spectroscopy is an excellent tool for determining low concentrations of additives in finished polypropylene pellets. This is demonstrated by monitoring the UV stabilizer Tinuvin 770 and the antioxidant Irganox 225. The application of multiple linear regression (MLR) models minimizes interferences that originate from different coating thicknesses and interferences in the polymer pellets.

This Application Note demonstrates how NIR spectroscopy can be used to determine the content of coatings on nylon fibers, quickly and without requiring either sample preparation or the use of reagents. In order to suppress the effects arising from scattering on the surface coatings, one forms the second derivative spectra; the linear least-squares regression method is used to calculate the calibration function.

This Application Note describes how NIR spectroscopy can be used to determine residual lignin content in wood pulp. Using the major absorbance peaks of both lignin and cellulose in the second derivative spectra, the residual lignin content in wood pulp can be monitored during paper production.

Determination of sodium laureth sulfate (SLES), cocamidopropyl betaine (CABP), cocamidopropylamine oxide (CAW), cocamide diethanolamine (DEA), and carbopol in shampoo is a cost- and time-intensive process due to the use of large volumes of chemicals per analysis. This application note demonstrates that the DS2500 Solid Analyzer operating in the visible and near-infrared spectral region (Vis-NIR) provides a cost-efficient and fast solution for a simultaneous determination these parameters in shampoo. With no sample preparation or chemicals needed, Vis-NIR spectroscopy allows for the complete analysis in less than a minute.

Polyvinyl alcohol (PVA) is a linear polymer, used in a variety of medical products (e.g. eye drops). Here, the degree of alcoholysis is an important index for the water solubility, viscosity, and adhesion of the product. The degree of alcoholysis is defined as the percentage of hydroxyl functional groups compared to the total functional groups accessible in the molecule. Conventional alcoholysis determination can take up to six hours per sample. Compared to the primary method, analysis with near-infrared spectroscopy (NIRS) only takes one minute. The following application note describes the determination of the degree of alcoholysis by NIRS.

Polydextrose is a low-calorie, synthetic polymer made of glucose. It is a recognized additive for foodstuffs. Hot water is used to extract the polydextrose from the foodstuff, after which it is centrifuged. Subsequent fermentation removes maltooligomers and fructans. Afterwards, the polydextrose is quantified using anion-exchange chromatography with pulsed amperometric detection.