Turbidimetric method for the determination of particle sizes in polypropylene/clay-composites during extrusion

Becker, Wolfgang; Guschin, Viktor; Mikonsaari, Irma; Teipel, Ulrich; Kölle, Sabine; Weiß, Patrick

doi:10.1007/s00216-016-0038-3

Cited by 11 publications

(8 citation statements)

References 24 publications

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“…Turbidity can be used to analyze the dispersion of solid particles in polymers, because they act as scattering obstacles to the passage of light. Particles can also be taken as tracers, for example, revealing their position in a flowing medium [ 37 ]. Due to the appearance of multiple scattering effects at large numbers of particles, the detection is limited to low volume concentrations of the disperse phase, typically up to 5% w/w, under which the linearity of the detector signal is obtained.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…Optical techniques are quite attractive for in-process monitoring, since they have fast response times and do not disturb the environment being analyzed. Small-angle light scattering (SALS) yields spatial information on flow-induced structures [ 32 ], whereas light beam attenuation, measured as birefringence or turbidity, is related to orientation [ 33 ] or dispersion of a second phase [ 34 ], providing information on shape [ 35 ] or size [ 36 , 37 ] of dispersed particles.…”

Section: Introductionmentioning

confidence: 99%

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On-Line Optical Monitoring of the Mixing Performance in Co-Rotating Twin-Screw Extruders

2022

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The use of real-time techniques to evaluate the global mixing performance of co-rotating twin-screw extruders is well consolidated, but much less is reported on the specific contribution of individual screw zones. This work uses on-line flow turbidity and birefringence to ascertain the mixing performance of kneading blocks with different geometries. For this purpose, one of the barrel segments of the extruder was modified in order to incorporate four sampling devices and slit dies containing optical windows were attached to them. The experiments consisted in reaching steady extrusion and then adding a small amount of tracer. Upon opening each sampling device, material was laterally detoured from the local screw channel, and its turbidity and birefringence were measured by the optical detector. Residence time distribution curves (RTD) were obtained at various axial positions along three different kneading blocks and under a range of screw speeds. It is hypothesized that K, a parameter related to the area under each RTD curve, is a good indicator of dispersive mixing, whereas variance can be used to assess distributive mixing. The experimental data confirmed that these mixing indices are sensitive to changes in processing conditions, and that they translate the expected behavior of each kneading block geometry.

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Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On-Line Optical Monitoring of the Mixing Performance in Co-Rotating Twin-Screw Extruders

2022

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“…Becker et al [50] used inline-visible spectrophotometry to determine particle size distribution density of polypropylene/clay composites. Particle distribution density was obtained from transmission spectra and using numerical linear equation systems.…”

Section: Uv/visible Spectrophotometrymentioning

confidence: 99%

An update on the contribution of hot-melt extrusion technology to novel drug delivery in the twenty-first century: part I

Kallakunta

Sarabu

Bandari

et al. 2019

Expert Opinion on Drug Delivery

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Introduction: Currently, hot melt extrusion (HME) is a promising technology in the pharmaceutical industry, as evidenced by its application to manufacture various FDA-approved commercial products in the market. HME is extensively researched for enhancing the solubility and bioavailability of poorly water-soluble drugs, taste masking, and modifying release in drug delivery systems. Additionally, its other novel opportunities or pharmaceutical applications, and capability for continuous manufacturing are being investigated. This efficient, industrially scalable, solvent-free, continuous process can be easily automated and coupled with other novel platforms for continuous manufacturing of pharmaceutical products. Areas covered: This review focuses on updates on solubility enhancement of poorly watersoluble drugs and process analytical tools such as UV/visible spectrophotometry; near-infrared spectroscopy; Raman spectroscopy; and rheometry for continuous manufacturing, with a special emphasis on fused deposition modeling 3D printing. Expert opinion: The strengths, weakness, opportunities, threats, (SWOT) and availability of commercial products confirmed wide HME applicability in pharmaceutical research. Increased interest in continuous manufacturing processes makes HME a promising strategy for this application. However, there is a need for extensive research using process analytical tools to establish HME as a dependable continuous manufacturing process.

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“…[26,27] A series of studies exist in the literatures that characterize the dispersion state using NIR spectroscopy. Becker et al [28] installed transmission NIR probes at the extruder die and monitored nanoparticle size distribution of a polypropylene (PP)/clay-composite by a turbidimetric method. Barbas et al [29] used on-line oscillatory rheometer and in-line NIR spectroscopy to investigate the dispersion evolution of a polymer-clay system during compounding.…”

Section: Introductionmentioning

confidence: 99%

In‐line characterization of dispersion uniformity evolution during a twin‐screw blending extrusion based on near‐infrared spectroscopy

Zhang

Lei

et al. 2020

Polymer Engineering & Sci

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Properties of an immiscible polymer blend have been proved to be closely related to dispersion uniformity of the minor phase. At present, dispersion uniformity is difficult to evaluate during the blending process, resulting in hysteretic feedback. Aiming at this problem, this work utilized near‐infrared (NIR) spectroscopy to in‐line characterize dispersion uniformity evolution during a twin‐screw extrusion. A multichannel NIR measurement system was set up and applied to evaluate the blending process of polypropylene and polyolefin elastomer (POE). Based on the NIR spectra collected at different positions of the extruder, five prediction models of POE content were established using the light gradient boosting machine algorithm. Dispersion uniformity was characterized through the fluctuation of the predicted content. The evolution of dispersion under such processing parameters was consistent with scanning electron microscopy.

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Turbidimetric method for the determination of particle sizes in polypropylene/clay-composites during extrusion

Cited by 11 publications

References 24 publications

On-Line Optical Monitoring of the Mixing Performance in Co-Rotating Twin-Screw Extruders

On-Line Optical Monitoring of the Mixing Performance in Co-Rotating Twin-Screw Extruders

An update on the contribution of hot-melt extrusion technology to novel drug delivery in the twenty-first century: part I

In‐line characterization of dispersion uniformity evolution during a twin‐screw blending extrusion based on near‐infrared spectroscopy

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