Innovative on-line near-infrared (NIR) spectroscopy to estimate content of each phase in composite polymer particles prepared by seeded emulsion polymerization

How to on-line analyze the morphology of composite polymer particles is a great challenge to develop the high-performed polymer nanoparticle materials, not only academia aspect but also industrial applications. We aim to on-line detect the weight fraction of each phase in composite polymer particles with a multilayered structure during emulsion polymerization. This work is also hoped to contribute to the development of on-line analysis on the morphology of composite polymer particles in the future. The weight fractions of core phase, interfacial layer, and shell layer (W-c, W-i, and W-s, respectively) in the multilayered composite polymer particles prepared by semi-continuous seeded emulsion terpolymerization of styrene (St), butyl acrylate (BA), and methyl methacrylate (MMA) with the existence of St-BA copolymer seed particles were successfully analyzed by using on-line near-infrared (NIR) spectroscopy for the first time on the basis of the results obtained by multi-frequency temperature-modulated differential scanning calorimetry (TOPEM-DSC), where NIR calibration models on W-c, W-i, and W-s were successfully established. By using NIR spectroscopy and the established models, the values of W-c, W-i, and W-s could be accurately on-line detected. It is suggested that there is a possibility to estimate the formation of unique morphology in composite polymer particles by on-line NIR measurement. (C) 2018 Elsevier B.V. All rights reserved.