Polymer Processing
References
•Billmeyer* Ch. 17, 18
•Elias** Ch. 14
*Textbook of Polymer Science 2nd Ed.
Wiley-Interscience, New York (1962,1971)
**An Introduction to Polymer Science
VCH, New York (1997)
Legacy Lecture of Fall 2000
This lecture was contributed by the MS-I class of Fall 2000.
Left to Right
Nhan Thai, Lee Madsen, Lu Ziqiang, Zu Yichuan, Nikhil Gupta
Simon Mwongela, Andrea Dupre, Mariah McMasters, Vera Verdree, Angela Davis
Nadia Edwin, Thomas Morgan, Amy Morara, Xiaoming Liang
Missing: Justin Mecomber
Not just one polystyrene
Selected PS grades from BASF. VEF=very easy flow; HM=high molar mass; HR = heat resistant.
Taken from Elias, Ch. 14. Processing engineers select grades using data such as these, perhaps relying
on such numbers more than the molecular data such as M or Rg that chemists are used to.
Physical
Property
Viscosity
Number
Heat
Distortion
Temp B
Heat
Distortion
Temp B
Vicat
Temp A
Vicat
Temp B
Young's
Modulus
Creep
Modulus
Tensile
strength
Fracture
elongation
Impact
strength
Notched
Impact
Strength
Test
Condition
?
Unit
Grade
VEF
74
EF
96
HM
119
HR
96
HM-HR
119
0.45 MPa
o
80
82
84
98
98
1.8 MPa
o
70
72
76
86
86
10 N
o
88
88
92
106
106
50 N
o
84
84
89
101
101
1 mm/min
MPa
3150
3200
3150
3200
3250
1000 h
MPa
?
2300
2830
2700
2850
5 mm/min
MPa
46
50
56
50
63
5 mm/min
%
1.5
2
2
2
3
-30 to + 23 oC
kJ/m2
6
9
11
10
13
-30 to + 23 oC
kJ/m2
2
2
2
2
2
mL/g
C
C
C
C
Note how completely unmolecular!
What molecular properties do
you suppose correspond to EF,
HR or HM?
Back to the Beginning
Early in the course, we tried several ways to categorize polymers, such as
condensation vs. addition, etc. From a processing point of view, the main
classes are:
Thermoplastic: the resin is heated to make a viscous liquid and then
processed into a usable object without much additional chemistry. Example:
polyethylene, polystyrene.
Thermoset: upon heating, further reaction occurs to make molecules “set up”
into a useful product. Chemistry occurs, so these are sometimes called
“reactive polymers”. The resin may be provided as either small molecules or
“prepregs”—partially polymerized stuff. Example: polyurethanes, phenolformaldehyde, melamine-formaldehyde, epoxy glue.
Compression Molding
Heat and
Cooling
Heat and
Cooling
Compound to be molded
Platen
Mold
Plunger
Guide
Pins
Mold
Cavity
Platen
Hydraulic
Pressure
Hydraulic
Plunger
Redrawn by Nikhil Gupta and Yichuan Xu from Billmeyer Fig. 17-1
Injection Molding
Nozzle
Feed hopper,
contains polymer pellets
Hydraulic
Pressure
Redrawn by Ziqiang Lu and Andrea Dupre from Billmeyer Fig. 17-2
Blow Molding—e.g. milk bottle
Plastic
Extruded ParisonMold Open
Mold Closed and Bottle
Blown
Redrawn by Thomas Morgan from Billmeyer Fig.17-3
Finished Bottle
Removed from Mold
Four-roll calender
Wad of plastic
To conditioning
equipment
Based on Billmeyer Fig. 17-4 (references Winding 1961)
A Plastics Extruder—e.g. tubing
Feed hopper
Heaters
Cores for
cooling water
Drive shaft
Die
Screw
Redrawn from Billmeyer 17-5 by Xiaoming Liang
Fiber Drawing
Heater (Optional)
Stretching Zone
Drive roll
Control
rolls
Snubbing
pin
2
(2 > 1)
1
Skewed idler roll
Drawn yarn to
bobbin
Undrawn
pretwisted yarn
Redrawn by Nadia Edwin from Billmeyer 18-5 (Riley 1956)
Melt Spinner
Polymer
Chips/Beads
Melting
Zone
Heating Grid
Pool
Metered
Extrusion
(controlled
flow)
Pump
Filter and
Spinneret
Air Diffuser
Extruded Fiber Cools
and Solidifies Here
Moisture
Conditioning
Steam
Chamber
Lubrication
by oil disk
and trough
Feed
rolls
Packaging
Redrawn by Lee Madsen
From Billmeyer 18-4, citing Riley 1956
Yarn
driver
Bobbin
Bobbin drive
Dry Spinning
Filtered
polymer
solution
Dry Spinning of Fibers
from a Solution
Feed
Metered
extrusion
Pump
Filter and
spinneret
Solidification
by solv ent
evaporation
Heated
chamber
Feed roll
and guide
Lubric ation
Air
inlet
Yarn driv ing
Balloon guide
Packaging
Ring and traveler
Bobbin transverse
Spindle
Wet Spinning (e.g. Kevlar)
Cotton
Dry Spun Acetate
Need tenacity vs. Elongation
Plot—a Student Project like
Billmeyer 18-1
Fiber properties for textile use
Chemical
Stability to:
 Acid
 Base
 Bleach
 Solvents
 Heat
 Sunlight
 Aging
Flammability
Ease of drying
Physical
Mechanical
 Tenacity
 Elongation
 Stiffness
 Flex cycles
 Abrasion
resistance
 Work recovery
 Tensile recovery
Thermal
 Melting Point
 Softening Point
 Tg
 Tdecompose
Biological
Toxicological
Dematological
Resistance:
 Bacteria
 Molds
 Insects
Fabric Qualities
Appearance
 Drape
 Hand
 Luster
(Kawabata machine
can measure)
Permeability
 Can protect
against
biotoxins?
Comfort
 Warmth
 Water sorption
 Moisture
retention
 Wicking
Electrical
 Surface
resistivity
(static)
Sensors
 Can detect
pathogens?
Stability
 Shape
 Shrinkage
 Felting
 Pilling
 Crease
resistance or
retention
Wetability
Adapted from Billmeyer Table 18-1.