Application Progress of Near-Infrared Spectroscopy in the Polymer Field

Near-infrared (NIR) spectroscopy analytical technology has been applied more and more widely in polymer field, since it can provide rich information about structure and composition of samples, and has the prominent feature of fast analysis without dealing with the sample. This article reviewed the research progress of the application of NIR spectroscopy in all aspects in polymer's entire life, which involves polymer synthesis, processing and recycling. NIR analytical technology can be used in quantitatively measurement of important material parameters during the polymer synthesis and processing, what's more, due to the good chemical and thermal stability of the optical fiber, it can realize the in-line real-time measurement in environment with strong corrosion, high temperature and high pressure. As for polymer synthesis, the research progress in real-time measurement of polymerization conversion, polymer particle size and copolymer composition with NIR spectroscopy was discussed. With regard to polymer processing, the discussion on application of NIR spectroscopy for in-line measurement of important parameters which reflects the processing state of the material during the reactive extrusion process, such as the polymer molecular weight, the content of residual monomer and the polymer grafting degree, was mainly made. In the recycling of plastics, NIR can be applied for the qualitative classification and identification of waste plastic products, the article analyzed the research status of this application at home and abroad. In addition, the problems in the application of NIR analytical technology in polymer analysis and corresponding suggestions were pointed out. Finally, the development direction of this technology in polymer field was discussed. It is believed that, NIR spectroscopy will have a wider application prospect in polymer field with the deepening of research work and the development of in-line measurement instruments.