Download - 1 Conferencia Magistral - Osswald
-
8/3/2019 1 Conferencia Magistral - Osswald
1/42
Mixing
Distributive and Dispersive Mixing in Extrusion Processes
Polymer Engineering Center
University of Wisconsin-Madison
1
Tim A. Osswald
-
8/3/2019 1 Conferencia Magistral - Osswald
2/42
Mixing
Rayleigh disturbances
Thread formation
Hole formation due tointerfacial instabilities
Pellet
Film ribbon formation
Distribution
Dispersion
Coalescence
Morphology withg
compatibilizer
Morphology withoutcompatibilizer
u
2
-
8/3/2019 1 Conferencia Magistral - Osswald
3/42
Distributive Mixing
3
-
8/3/2019 1 Conferencia Magistral - Osswald
4/42
Distributive Mixing
0
A0
A0A0
A(t)
(t)
4
-
8/3/2019 1 Conferencia Magistral - Osswald
5/42
Distributive Mixing
= 0o
= 90o A(t)
A0= cosGrowth:
Orientation:
Deformation:
90o
90o
=
t
0
dt
5
-
8/3/2019 1 Conferencia Magistral - Osswald
6/42
Distributive Mixing
Erwin/Ng (1980)6
-
8/3/2019 1 Conferencia Magistral - Osswald
7/42
A
A0=
2
2
A
A0=
3
3
A
A0=
NN
A
A0=
A
A0 e
/2
Distributive Mixing
100
2,500
37,000
5E21
100
Erwin/Ng (1980)7
-
8/3/2019 1 Conferencia Magistral - Osswald
8/42
Schematic diagram of a Kenics static mixer
Distributive Mixing
8
-
8/3/2019 1 Conferencia Magistral - Osswald
9/42
Experimental progression of the
layering of colored resins in aKenics static mixer
Entrance
Exit
Distributive Mixing
9
-
8/3/2019 1 Conferencia Magistral - Osswald
10/42
Schematic diagram of a co-kneater
Distributive Mixing
10
-
8/3/2019 1 Conferencia Magistral - Osswald
11/42
Typical pin and slotted flight type
single screw extruder distributive
mixing sections.
Distributive Mixing
11
-
8/3/2019 1 Conferencia Magistral - Osswald
12/42
Unwrapped channel contents of a pin barrel extruder.
Distributive Mixing
12
-
8/3/2019 1 Conferencia Magistral - Osswald
13/42
Distributive Mixing
Boundary Element Model of Static Mixer
Gramann/Osswald (2000)13
-
8/3/2019 1 Conferencia Magistral - Osswald
14/42
Distributive Mixing
Boundary Element Model of Static MixerPressure Distribution
Gramann/Osswald (2000)14
-
8/3/2019 1 Conferencia Magistral - Osswald
15/42Gramann/Osswald (2000)
Boundary Element Model of Static Mixer
Streamlines
Distributive Mixing
15
-
8/3/2019 1 Conferencia Magistral - Osswald
16/42
f(t)
F
(t
)F(t) =
t
0
f(t)dt
0 t
t = 0
t = t
Residence Time Distribution
Residence Time Distribution
Cummulative
Residence Time Distribution
-
8/3/2019 1 Conferencia Magistral - Osswald
17/42
Distributive MixingResidence Time Distribution
The Perfect Mixer
(1 C0)Q
C0Q
Q
Q QQ
Residence Time Distribution
17
-
8/3/2019 1 Conferencia Magistral - Osswald
18/42
Various rhomboidal single screw extruder distributive mixing sections.
Distributive Mixing
Rios/Osswald (2000)18
-
8/3/2019 1 Conferencia Magistral - Osswald
19/42
Distributive Mixing
Rios/Osswald (2000)19
-
8/3/2019 1 Conferencia Magistral - Osswald
20/42
Distributive Mixing
Rios/Osswald (2000)20
-
8/3/2019 1 Conferencia Magistral - Osswald
21/42
Dispersive mixing of a solid agglomerate
Dispersive MixingSolid agglomerates (Carbon black) into a polymer (Rubber)
21
-
8/3/2019 1 Conferencia Magistral - Osswald
22/42
Dispersive Mixing
Felongation = 6r2
22
-
8/3/2019 1 Conferencia Magistral - Osswald
23/42
Schematic diagram of an internal batch mixer
Fraction below 50nm
Dispersive Mixing
Manas/Tadmor (1980)23
-
8/3/2019 1 Conferencia Magistral - Osswald
24/42
PA6 Thread
PS Matrix
Dispersive Mixing (Grace Diagram)Incompatible liquids (Polymer Blends)
Dispersive mixing of incompatible liquids
0 sec 1 sec 2 sec 3 sec 4 sec
Meijer24
-
8/3/2019 1 Conferencia Magistral - Osswald
25/42
Dispersive Mixing (Grace Diagram)Incompatible liquids (Polymer Blends)
Ca 0
Ca < CacritCa = Cacrit
Ca =R
s
= SHEAR FLOW
25
-
8/3/2019 1 Conferencia Magistral - Osswald
26/42
SHEAR FLOW
Cacrit
100
101
02
106
10310
0101
.......................
3.
8
Dispersive Mixing (Grace Diagram)Incompatible liquids (Polymer Blends)
drop
matrix
26
-
8/3/2019 1 Conferencia Magistral - Osswald
27/42
Dispersive Mixing (Grace Diagram)Incompatible liquids (Polymer Blends)
Ca 0
Ca =R
s
=
Ca < CacritCa = Cacrit
ELONGATIONAL FLOW
27
-
8/3/2019 1 Conferencia Magistral - Osswald
28/42
SHEAR FLOW
Cacrit
100
101
02
106
10310
0101
.......................
3.
8
Dispersive Mixing (Grace Diagram)Incompatible liquids (Polymer Blends)
drop
matrix
ELONGATIONAL FLOW
28
-
8/3/2019 1 Conferencia Magistral - Osswald
29/42
Typical single screw extruder distributive mixing sections with dispersive capabilities
Dispersive Mixing
29
-
8/3/2019 1 Conferencia Magistral - Osswald
30/42
Commonly used single screw extruder dispersive mixing section
Dispersive Mixing
30
-
8/3/2019 1 Conferencia Magistral - Osswald
31/42
Twin screw extruders
Dispersive Mixing
31
-
8/3/2019 1 Conferencia Magistral - Osswald
32/42
Dispersive Mixing (Blends)
Co-Rotating Twin screw extruder (Commonly used today)
32
-
8/3/2019 1 Conferencia Magistral - Osswald
33/42
Dispersive Mixing (Blends)
Counter-Rotating Twin screw extruder (Not commonly used today)
33
-
8/3/2019 1 Conferencia Magistral - Osswald
34/42
Schiffer/Osswald 200
-
8/3/2019 1 Conferencia Magistral - Osswald
35/42
Schiffer/Osswald 200
-
8/3/2019 1 Conferencia Magistral - Osswald
36/42
Schiffer/Osswald 200
-
8/3/2019 1 Conferencia Magistral - Osswald
37/42
Schiffer/Osswald 200
-
8/3/2019 1 Conferencia Magistral - Osswald
38/42
Schiffer/Osswald 200
-
8/3/2019 1 Conferencia Magistral - Osswald
39/42
Krawinkel/Osswald 2
-
8/3/2019 1 Conferencia Magistral - Osswald
40/42
Krawinkel/Osswald 2
-
8/3/2019 1 Conferencia Magistral - Osswald
41/42
Schiffer/Osswald 200
-
8/3/2019 1 Conferencia Magistral - Osswald
42/42
Distributive mixing governed by deformation
and orientation
Dispersive mixing governed by stresses
Elongational flows are preferred for both
distributive and dispersive mixing
Elongational flows lead to lower energy
consumption and consequently lower viscousheating
CONCLUSIONS