In‐line characterization of polypropylene nanocomposites using FT‐NIR

Abstract

The morphology of polymer nanocomposites is usually characterized by various methods like X-ray diffraction (XRD) or transmission electron microscopy (TEM). In this work, a new approach for characterizing nanocomposites is developed: the results of small angle x-ray scattering, on-line extensional rheometry (level of melt strength) and Young's modulus out of tensile test are correlated with those of near infrared (NIR) spectroscopy. The disadvantages of the common characterization methods are high costs and very time consuming sample preparation and testing. In contrast, NIR spectroscopy has the advantage to be measured inline and in real time directly in the melt. The results were obtained for different aggregate states (NIR spectroscopy and on-line rheotens test in melt state, tensile test, and XRD in solid state). Therefore, important factors like crystallization could not be considered. Nevertheless, this work demonstrates that the NIR-technology is perfectly suitable for quantitative in-line characterization. The results show that, by the installation of a NIR spectrometer on a nanocomposite-processing compounder, a powerful instrument for quality control and optimization of compounding process, in terms of increased and constant quality, is available.

Characterization of polymer nanocomposites based on layered silicates

“…Normally a gallery period of the nanofiller is determined on a powder sample. Figure 4.1 shows the sax curves for an intercalated and an exfoliated nanocomposite [4]. To determine the gallery period, scattering curves are corrected for background scatter and a Lorenz correction is afterward applied.…”

“…[4], the NIR spectroscopy was used for characterizing polyethylene nanocomposites with the help of reference values out of small-angle X-ray scattering, online extensional rheometry (level of melt strength) and Young's modulus (obtained from tensile tests. [4], the NIR spectroscopy was used for characterizing polyethylene nanocomposites with the help of reference values out of small-angle X-ray scattering, online extensional rheometry (level of melt strength) and Young's modulus (obtained from tensile tests.…”

Process monitoring and visualization solutions for hot-melt extrusion: a review

“…Witschnigg et al [67] developed an NIR method where the results of on-line extensional rheometry (on-line measurements of drawing force performed by on-line Rheotens equipment), Young's modulus (calculated out of tensile tests) and interlayer distance (determined by small-angle X-ray scattering) are correlated with in-line NIR spectra. A mixture of 90% polypropylene (PP), 5% organoclay and 5% compatibilizer (w/w) was extruded in a corotating twin-screw extruder that had a bypass system to create a melt string for on-line rheotens measurements.…”

Rapid and nondestructive quantitative analysis of natural rubber blends regardless of geographical origin and harvest time of the natural rubber

“…Because the absorptivities of vibrational overtone and combination bands in NIR region are orders of magnitude lower than that of vibrational fundamental bands in infrared region, this can greatly increase penetration depth 23 (usually from 5 to 10 mm), and improve the accuracy and precision of the results. NIR has been used for quantitative analysis for plastic [24][25][26][27] and single synthetic rubber, 23,28,29 and SBR (styrenebutadiene rubber)/NBR (acrylonitrile-butadiene rubber) as well. 6 However, up to date, little work has been reported on NIR analysis towards natural rubber (NR) blend.…”