Transcript Chapter 2c - Loy Research Group

Chapter 2c
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Old Chem 309
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Polymerization Techniques
• Bulk-no solvent just monomer +
catalysts
• Solution Polymerization-in solvent
• Suspension-micron-millimeter spheres
• Emulsion-ultrasmall spheres
Bulk Polymerizations
Rare
Overheat & explode with scale up
No solvent-just monomer
Polymer usually vitrifies before done
Broad MW distribution
Acrylic sheets by Bulk polymerization of MMA
Storage of vinyl monomers in air = peroxide initiated
polymerizations
Tankcar of styrene
2005 in Ohio
Solution Polymerization
• Better control of reaction temperature
• Better control of polymerization
• Slower
• Not very green-residual solvent
Suspension Polymerization
• Oil droplets dispersed in water
• Initiator soluble in oil
• Greener than solution polymerization
Filter off particles of polymer
Emulsion
Polymerization
Still oil in water (or the reverse)
Initiator in water
Smaller particles (latex)
Excellent control of temp
Solution turns white
Polystyrene latex
Suspension
Monomer in oil
Initiator in oil
Emulsion
Mini-emulsion
Monomer in oil
Monomer in oil
Initiator in water
Initiator in water
Micro-emulsion
Monomer in oil
Initiator in water
Less Common Polymerization
Techniques
• Solid state polymerization
– Polymerization of crystalline monomers
• Diacetylene crystals
• Gas Phase polymerization
– Parylene polymerizations
• Plasma polymerization
– Put anything in a plasma
Solid State Polymerizations
Heating Oligomeric Condensation Polymers
Tg < X < Tm
O
O
O
HO
O
O
O
O
O
n
O
OH
HO
OH
O
O
250 °C
O
Tg = 67 °C and Tm = 265 °C
Nylons, Polyesters
Nylon 66 Tg = 70 °C and Tm = 264
°C
O
O
O
O
n
O
Solid State Polymerizations
Topological Polymerizations: Polymerization of crystals
Quinodimethane polymerizations
Di- and Triacetylene polymerizations
In single crystals
Solid State Polymerizations of Fullerenes
Topological polymerization in 3-D
Gas Phase Polymerization
1) Light olefins
2) Parylenes
LIGHT OLEFINS
Ethylene and propylene
Rotational Molding
1%
Blow Molding
14%
Other Extrusion Wire and Cable
2%
3%
Pipe and Conduit
7%
Sheet
2%
Extrusion Coating
4%
Film
• Food Packaging
• Hygiene & Medical
• Consumer & Ind. Liners
• Stretch Films
• Agricultural Films
• HDSS
Injection Molding
12%
Other Non-Extrusion
3%
Film
51%
2004 Global PE Demand: 136 Billion Pounds
Types of Polyethylene
HDPE (0.940-0.965)
“High Density”
LLDPE (0.860-0.926)
“Linear Low Density”
O
O
O
C-OH
O
O
O
LDPE (0.915-0.930)
“Low Density”
O
O
O
O
O
High Pressure Copolymers
(AA, VA, MA, EA)
Gas Phase Polymerization: Light olefins
Oxygen initiator
2-3K atmospheres
250 °C
Gas Phase Polymerization: Light olefins
Fluidized bed polymerization
MORE FLEXIBLE
Gas Phase Polymerization: Paralene
Gas phase
Polymerizes on contact
Conformal coatings
Pinhole free
Preserving artifacts (paper)
Microelectronics
Medical devices
Plasma Polymerization
•500 Å - 1 micron thick films
•Continuous coatings
•Solvent free
•High cohesion to surface
•Highly cross-linked
•Generally amorphous
Plasma Polymerization
Monomers: Hydrocarbons
Double or triple bonds nice, not necessary
Fluorocarbon
Tetraalkoxysilanes (for silica)
Plasma Polymerization
Fig1. Bell-jar type reactors
Fig 2. Tubular-type reactors
P- pumps; PS-power supply; S-substrate
M-feed gas inlet; G-vacuum gauge
Plasma Polymerization
Multi-layer bottles
No loss of fizz
PET [Poly(Ethylene Terephthalate)]
Characterization of Polymers
• 1H & 13C Nuclear Magnetic Resonance
spectroscopy (NMR)
• Infrared spectroscopy (Fourier
Transform IR)
• Elemental or combustion analyses
• Molecular weight
13C
NMR is a very powerful way to determine
the microstructure of a polymer.
2
1
1
2
13C
NMR shift is sensitive to the two
stereocenters on either side on sptectrometers
> 300 MHz. This is called pentad resolution.
r
m
m
r
m
r
mmrm pentad
m = meso (same orientation)
r = racemic (opposite orientation)
13C
NMR spectrum of CH3 region
of atactic polypropylene
Infrared Spectroscopy: Bond vibrations
C=C-H
polystyrene
C-H
C=C
stretch
2-16 Micron wavelength range
Infrared Spectroscopy: Bond vibrations
C-H bend
C=O
C-O
C-H
stretch
Poly(methyl methacrylate)
Types of Addition Polymerizations
Anionic
Ph
C3H7
Li
n
Li+
C4H9
Ph
Li+
C4H9
n
Ph
Ph
Ph
Radical
PhCO2•
Ph
n
Ph
PhCO2
n
Ph
Cationic
Ph
Cl3Al OH2
PhCO2
Ph
Ph
n
Ph
H
HOAlCl3
H
Ph
HOAlCl3
n
Ph
Ph
Chemical Modification of Polymers
1) Hydrolysis
polyvinyl alcohol
Polyvinylacetate
NaOH
n
O
O
2) Oxidation
n
O
H3C
OH
H2O
O
n
CH3
Poly ethylene oxide
O
hv, O2
O
H
3) Photochemistry
(can be oxidation or not)
4) Chemical crosslinking
Na+
Me
n
Polysilane
R R R R
Si
Si
Si
Si
Si
R R R R R R
H
h: UV
O2
S8

polybutadiene
5) Chemical modification
See next slide
H
or ascorbic
acid
R
R O Si R
Si
O
R
O
Si R
Si O R
R
R
S
S
S
Chemical Modification of Polyvinyl Alcohol to make
Polyvinyl butyral for safety glass
polyvinyl alcohol
poly vinyl butyral
CH3CH2CH2CHO
OH
OH OH
O
OH OH
O
OH
O
No PVB
With PVB
O
Bullet Proof Glass
Making bullet proof glass
glass, laminates and polycarbonate sheets
are interlaid in a clean room to ensure
clarity. In our large autoclave, superheated
steam seals the layers together.
Polycarbonate is
Strong Material
Young's modulus (E)
Tensile strength (σt)
2-2.4 Gpa
55-75 Mpa
Exploding CD’s
Mythbusters:
> 23,000 rpm CD will shatter
Scratches or defects are the culprit
52X drive -MAX: 27,500 rpm
typical: 11,000 rpm
10,000 RPM = 65 m/s = 145 mph
7200 gravities of acceleration
And approx. 5 MPa stress
Yield Strength 60 MPa
Nalgene
Polycarbonate Properties
Density:
Young's modulus (E)
Tensile strength (σt)
Elongation (ε) @ break
Glass transition (Tg)
Melting (Tm)
Upper working temperature
$7.3-11/kg
1.2 g/cc
2-2.4 Gpa
55-75 Mpa
80-150%
150 °C
267 °C
115-130 °C
Bisphenol and Endocrine System
100-250 g bisphenol per Liter water in water bottles
20 g/Liter per day can disrupt mouse development
vom Saal, F.S., Richter, C.A., Ruhlen, R.R. Nagel, S.C. and Welshons, W.V. Disruption of laboratory
experiments due to leaching of bisphenol a from polycarbonate cages and bottles and uncontrolled variability
in components of animal feed. Proceedings from the International Workshop on Development of ScienceBased Guidelines for Laboratory Animal Care, National Academies Press, Washington DC, 65-69, 2004.
Immune system
Antioxidant enzymes
Decreases plasma testosterone
Learning disabilities
vom Saal, F.S., Nagel, S.C., Timms, B.G. and Welshons, W.V. Implications for human health of the extensive bisphenol A
literature showing adverse effects at low doses: A response to attempts to mislead the public. Toxicology, 212:244-252,
2005.
Nalgene Substitutes-food and water
•
•
•
•
Glass (blender, pitchers, glasses)
Metal (water bottles)
Polyethylene (water bottles)
Polyamide or Nylon (baby bottles)