• Title/Summary/Keyword: polymer rheology

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In-line measurement of residence time distribution in twin-screw extruder using non-destructive ultrasound

  • Lee, Sang-Myung;Park, Jong-Cheol;Lee, Sang-Mook;Ahn, Young-Joon;Lee, Jae-Wook
    • Korea-Australia Rheology Journal
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    • v.17 no.2
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    • pp.87-95
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    • 2005

  • In this study, we performed RTD measurement at the die exit of co-rotating twin-screw extruder using a non-destructive ultrasonic device. The ultrasonic device was attached at slit die and was composed of a steel buffer rod and 10 MHz longitudinal piezoelectric ultrasonic transducer. This in-line ultrasonic monitoring method is based on the ultrasonic response of $CaCO_3$ filled in polymer. The RTD is evaluated by variation of ultrasonic attenuation with time caused by change of the tracer concentration during extrusion. The ultrasonic tracer, pellet type of compounded $CaCO_3$ in polymer was used in this study. The effects of tracer concentration on RTD and flow patterns were studied. Evaluation for the residence functions at different screw speeds, feeding rates and screw configurations were also carried out.

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Scaling analysis of electrorheological poly(naphthalene quinone) radical suspensions

  • Min S. Cho;Park, Hyoung J.
    • Korea-Australia Rheology Journal
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    • v.12 no.3_4
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    • pp.151-155
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    • 2000

  • A semiconducting poly(naphthalene quinone) radical (PNQR) was synthesized from Friedel-Craft acylation between naphthalene and phthalic anhydride and used as dispersing particles of a dry-base electrorheological (ER) material in silicone oil. Under an applied electric field (E), the dynamic yield stress (${\tau}_{dyn}$) of this ER fluid, obtained from a steady shear experiment with a controlled shear rate mode, was observed to increase with $E^{1.45}$ Based on this relationship, we propose a universal correlation curve for shear viscosity, which is independent of E using a scaling analysis.

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Reaction Kinetics and Morphological Changes at Polymer-polymer Interface measured by Rheological Properties (유변학적 성질 측정으로 측정한 고분자 계면에서의 반응 kinetics와 morphology 변화)

  • Kim, Hwang-Yong;Unyong Jeong;Kim, Jin-Kon
    • Proceedings of the Korean Society of Rheology Conference
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    • 2002.05a
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    • pp.25-27
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    • 2002

  • In this study we investigated the reaction kinetics by a convenient but useful method-rheology to characterize the interface between two immiscible blends with a Reactive compatibilizer. Also, we made an attempt to correlate changes of interface roughness with rheological properties. The blend systems employed in this study was mono-carboxylated polystyrene (PS-mCOOH) and an poly(methyl methacrylate-ran-glycidylmethacrylate) (PMMA-GMA). PS-mCOOH was synthesized by an anionic polymerization and PMMA-GMA by a free radical polymerization. We prepared two plates of each polymer using compression molding with a smooth surface molder, then put one upon another. As soon as these two plates welds together inside a rheometer under nitrogen environment, the torque and moduli were obtained with reaction time at different temperatures. Through the analysis of this modulus change with reaction time, we estimated interfacial reaction and roughening. The increment of modulus in initial state can be correlated to the extent of reaction. We obtained the reaction kinetic constant by fitting appropriate kinetic equation into experimental data. We also showed that increment of modulus in later state was due to by roughened interface.

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