Flow behavior in a corotating twin-screw extruder of pure polymers and blends: Characterization by fluorescence monitoring technique

The objective of this work was to investigate the flow behavior of pure polymers and blends, especially miscible polymer/polymer systems, in a corotating twin-screw extruder (TSE) using an online fluorescence monitoring device. An immiscible blend was also studied for the sake of comparison. The fluorescence signal was obtained by using synthesized fluorescence tracers added to the melt at very low concentrations. These tracers consisted of two styrene-maleic anhydride copolymers (SMA) labeled with anthracene. The investigated blends were SMA8 (8 wt % of MA in SMA)/polystyrene (PS), SMA14 (14 wt % of MA in SMA)/styrene acrylonitrile copolymer (SAN), and poly(methyl methacrylate) (PMMA)/ethyl acrylate-methyl methacrylate copolymer (PMMAEA). The residence time distribution (RTD), the mean residence time ((t) over bar), the dimensionless variance (sigma(2)(theta)), the Peclet number (Pe) and the fluorescence peak intensity distribution of pure polymers and binary polymer systems were investigated and interpreted in terms of polymers rheological properties. It was observed that polymers presenting higher viscosity or higher pressure showed longer residence time. A difference in behavior was also observed for the RTD of miscible and immiscible blends. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 2304-2312, 2011

[1]  José A. Covas,et al.  On-line monitoring of the residence time distribution along a kneading block of a twin-screw extruder , 2004 .

[2]  Robert Weiss,et al.  Development of an ionomer tracer for extruder residence time distribution experiments , 1989 .

[3]  S. V. Kao,et al.  Residence time distribution in a twin screw extruder , 1984 .

[4]  Bruno Vergnes,et al.  A study of residence time distribution in co-rotating twin-screw extruders. Part II: Experimental validation , 2003 .

[5]  D. Todd.  Residence time distribution in twin-screw extruders , 1975 .

[6]  G. Hu,et al.  Improved apparatus for inline measurement of residence time distribution of thermomechanically complex systems , 2006 .

[7]  P. Cassagnau,et al.  Study of mixing of liquid/polymer in twin screw extruder by residence time distribution , 2005 .

[8]  Sebastião V. Canevarolo,et al.  In‐line optical detection in the transient state of extrusion polymer blending and reactive processing , 2005 .

[9]  Philippe Cassagnau,et al.  An ultraviolet method for the determination of the residence time distribution in a twin screw extruder , 1991 .

[10]  J. White,et al.  Flow Visualization and Residence Time Distributions in a Modular Co-rotating Twin Screw Extruder , 1994 .

[11]  G. Hu,et al.  Preparation of macromolecular tracers and their use for studying the residence time distribution of polymeric systems , 1999 .

[12]  G. C. Walsh,et al.  Mean residence time analysis for twin screw extruders , 2000 .

[13]  Zhongbin Xu,et al.  Assessing local residence time distributions in screw extruders through a new in‐line measurement instrument , 2006 .

[14]  G. C. Walsh,et al.  Residence‐time distribution model for twin‐screw extruders , 1999 .

[15]  C. Tzoganakis,et al.  Measurements of residence time distribution for the peroxide degradation of polypropylene in a single‐screw plasticating extruder , 1989 .

[16]  F. M. Gallant,et al.  Fluorescence monitoring of twin screw extrusion , 1991 .

[17]  K. Jayaraman,et al.  Mixing in reactive extrusion of low-density polyethylene melts: Linear vs. branched , 1995 .

[18]  C. Panayiotou,et al.  Blends of polymers with similar glass transition temperatures: A DMTA and DSC study , 2004 .

[19]  M. Lambla,et al.  Effects of processing parameters on the in situ compatibilization of polypropylene and poly(butylene terephthalate) blends by one-step reactive extrusion , 1996 .

[20]  J. W. Barlow,et al.  Blends of styrene/maleic anhydride copolymers with polymethacrylates , 1991 .

[21]  Guo-Hua Hu,et al.  One-line measurement of the residence time distribution in screw extruders , 1999 .

[22]  W. I. Patterson,et al.  On-line Measurement of Residence Time Distribution in a Twin-screw Extruder , 1995 .

[23]  Sandrine Hoppe,et al.  Local residence time, residence revolution, and residence volume distributions in twin-screw extruders , 2008 .

[24]  A. Ajji,et al.  Miscibility characterization of SMA/SAN and SMA/PMMA blends by differential scanning calorimetry and fluorescence techniques , 2007 .

[25]  J. W. Barlow,et al.  Interactions in SMA‐SAN blends , 1989 .