The potential of near-infrared diffuse reflectance spectroscopy as a tool for characterizing the particle size of dispersion phase in polymer blends

In this study, we investigated the impact of the particle size of dispersion phase in polymer blends on the near-infrared (NIR) diffuse reflectance spectrum. Polypropylene/Polystyrene (PP/PS) blends with different particle sizes of dispersion phase were prepared at the weight ratio of 80/20. When compared to the spectra of the virgin PP, PS, and two-layer sheet of PP-PS, a clear baseline tilt is revealed by the spectrum of the PP/PS blends. By combining the diameter data of the particle size of the PS phase counted by SEM image, the reflectance of the spectrum decreases as the diameter of the particle size of the PS phase increases. In the Monte Carlo simulation results, the number of received scattering photons decreases with an increase in particle size and wavelength respectively, which can well explain the actual spectra variation. The volume mean diameter (Dv) predicted model was built through principal component regression, and the model showed good performance which correlation coefficient (R2) was 0.9532 and root mean square errors of calibration (RMSEC) was 0.2792 μm. [Display omitted] •The effect of particle size of dispersion phase of polymer blends on near-infrared diffused reflectance spectroscopy is studied.•The reflectance of the spectrum decreases as the diameter of the particle size of the dispersion phase increases.•Monte Carlo simulation results can well explain the actual spectra variation.•The volume mean diameter (Dv) predicted model was built through principal component regression which showed good performance.