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Output
(kg/h)
Actual
Speed
(RPM)
Actual
Torque
(Nm)
Actual
Specific
Energy
(kWh/kg)
Calculated
Mean
Residence
Time(s)
Calculated
Number of
Turns
Calculated
Mean
Shear Rate
(1/s)
Actual
Tensile
Strength
(Mpa)
Actual
Impact
Strength
(J/m)
200
560
248
0.119
14.4
134
235
27.7
29.8
300
800
270
0.13
9.6
128
335
28.2
30.5
400
1200
286
0.154
7.2
144
503
25.7
41.7
500
1500
340
0.174
6.48
162
628
24.6
42.8
900
1500
497
0.134
4
100
628
28.6
36.1
-7-
Game Changing
Technological Innovations in
MELT COMPOUNDING
THE EXTRUDER TIMES / ISSUE 10 / AUGUST 2010
Figure 7
Process Parameters vs Properties for PP
CoPolymer (11 MFI) with 40%Talc
It can be seen from the data that increase in tensile strength is correlated with the number of turns. It can also be seen that impact strength
is affected by the work done (specific energy). The process parameters exert a considerable amount of influence on physical properties to
the extent of 15 to 25%. It is possible to deduce from the data that certain behavior that is inherent to the material will finally limit further
improvements in properties. It should be noted that except at 200 RPM, all other outputs were run at residence time of less than 10
seconds.
This data helps bring into focus that other effects apart from shear are significant – for instance at low speeds, specific energy has marginal
influence on impact strength and it is possible that kneading action apart from shearing action has a role in affecting impact strength.