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In-line turbidity monitoring of the second phase droplets deformation during extrusion

Authors

  • L. Zborowski,

    1. PPG-CEM, UFSCar, Graduate Program in Materials Science and Engineering, Federal University of São Carlos, São Paulo, Brazil
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  • S.V. Canevarolo

    Corresponding author
    1. DEMa, UFSCar, Department of Materials Engineering, Federal University of São Carlos, São Paulo, Brazil
    • DEMa, UFSCar, Department of Materials Engineering, Federal University of São Carlos, São Paulo, Brazil. E-mail: caneva@ufscar.br

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Abstract

The dispersion and deformation of the second phase during extrusion of polymer mixtures were in real-time characterized using an in-line turbidimeter. Three polymer mixtures with constant concentration but very different viscosity ratios (1/4, 1, and 4) were reprocessed up to three times in a twin-screw extruder. After that they were processed again, having the extruder exit being blocked by an on/off valve, which controls the hold-on and discharge. The melt turbidity, a variable dependent of the droplets size and shape, was recorded during processing and controlled die-head pressure discharge. The deformation of the droplets is high and reversible in mixture having viscosity ratio close to 1, indicating no droplet breakup and/or coalescence. In contrast, for high viscosity ratios and high matrix elasticity a hysteresis is formed during deformation/recovery of the droplets. POLYM. ENG. SCI., 53:2422–2428, 2013. © 2013 Society of Plastics Engineers

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