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Chapter 2c. Bibliography due on Friday 11:59 PM Upload file on D2L. Office hours: Tuesday 1pm Monday & Wednesday 12-1 or e-mail for an appointment Old Chem 309 [email protected]. Polymerization Techniques. Bulk-no solvent just monomer + catalysts - PowerPoint PPT Presentation
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Chapter 2c
Office hours: Tuesday 1pmMonday & Wednesday 12-1or e-mail for an appointmentOld Chem 309
Bibliography due on Friday 11:59 PMUpload file on D2L.
Polymerization Techniques
• Bulk-no solvent just monomer + catalysts
• Solution Polymerization-in solvent
• Suspension-micron-millimeter spheres
• Emulsion-ultrasmall spheres
Bulk Polymerizations
RareOverheat & explode with scale upNo solvent-just monomerPolymer usually vitrifies before doneBroad MW distribution
Acrylic sheets by Bulk polymerization of MMA
Storage of vinyl monomers in air = peroxide initiated polymerizations
Tankcar of styrene2005 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 waterSmaller particles (latex)Excellent control of tempSolution turns white
Polystyrene latex
Suspension Emulsion Mini-emulsion Micro-emulsion
Monomer in oil Monomer in oil Monomer in oil Monomer in oil
Initiator in oil Initiator in water Initiator in waterInitiator 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
Nylons, Polyesters
O
O
O
O
O
HO O
O
O
n
O
O
O
O
O
O O
O
On
OH
250 °C
HOOH
Nylon 66 Tg = 70 °C and Tm = 264 °C
Tg = 67 °C and Tm = 265 °C
Solid State Polymerizations
Topological Polymerizations: Polymerization of crystals
Quinodimethane polymerizations
Di- and Triacetylene polymerizationsIn single crystals
Solid State Polymerizations of Fullerenes
Topological polymerization in 3-D
Gas Phase Polymerization
1) Light olefins2) Parylenes
LIGHT OLEFINS
Ethylene and propylene
2004 Global PE Demand: 136 Billion Pounds
• Food Packaging• Hygiene & Medical• Consumer & Ind. Liners• Stretch Films• Agricultural Films• HDSS
Film
SOURCE: Nexant/ChemSystems 2005, PTAI 1/05
Types of Polyethylene
O
OOO
O O
OO
O
O
C-OH
O
HDPE (0.940-0.965)“High Density”
LLDPE (0.860-0.926)“Linear Low Density”
LDPE (0.915-0.930)“Low Density”
High Pressure Copolymers(AA, VA, MA, EA)
Gas Phase Polymerization: Light olefins
Oxygen initiator2-3K atmospheres250 °C
Gas Phase Polymerization: Light olefins
Fluidized bed polymerization
MORE FLEXIBLE
Gas Phase Polymerization: Paralene
Gas phasePolymerizes on contactConformal coatingsPinhole freePreserving artifacts (paper)MicroelectronicsMedical 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: HydrocarbonsDouble or triple bonds nice, not necessaryFluorocarbonTetraalkoxysilanes (for silica)
P- pumps; PS-power supply; S-substrate
M-feed gas inlet; G-vacuum gauge
Fig1. Bell-jar type reactors Fig 2. Tubular-type reactors
Plasma Polymerization
Plasma Polymerization
PET [Poly(Ethylene Terephthalate)]Multi-layer bottlesNo loss of fizz
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.
13C NMR shift is sensitive to the two stereocenters on either side on sptectrometers > 300 MHz. This is called pentad resolution.
r mm rmr
mmrm pentad
m = meso (same orientation)r = racemic (opposite orientation)
12 1 2
13C NMR spectrum of CH3 region of atactic polypropylene
Infrared Spectroscopy: Bond vibrations
2-16 Micron wavelength range
polystyreneC=C-H
C-H
C=Cstretch
Infrared Spectroscopy: Bond vibrations
Poly(methyl methacrylate)
C=O
C-O
C-Hstretch
C-H bend
Types of Addition Polymerizations
Ph
Anionic
C3H7 Li C4H9
Ph
Li+ Phn
C4H9
Ph Ph
Li+
n
Ph
Radical
PhCO2•Ph
n
Ph
Cationic
Cl3Al OH2H
PhHOAlCl3
Phn
H
Ph Phn
HOAlCl3
PhCO2
PhPhCO2
Ph Phn
Chemical Modification of Polymers
1) Hydrolysis
2) Oxidation
3) Photochemistry (can be oxidation or not)
4) Chemical crosslinking
5) Chemical modification
O
OCH3
n NaOH
H2O OHn
O
O
H3Cn
Na+
Polyvinylacetate polyvinyl alcohol
On
H
Poly ethylene oxidehv, O2
or ascorbic acid
Me
O
H
SiSi
SiSi
SiR R
R R
R R
R R
R R
Polysilane
hν: UV
O2
SiOSi O
SiO
SiO
R RR
R
RR
R
R
H
polybutadiene
S8
Δ SS
S
See next slide
Chemical Modification of Polyvinyl Alcohol to make Polyvinyl butyral for safety glass
polyvinyl alcohol
OH OH OH OH OH
CH3CH2CH2CHO
O O OH O O
poly vinyl butyral
No PVB
With PVB
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.
Making bullet proof glass
Polycarbonate is Strong Material
Young's modulus (E) 2-2.4 Gpa
Tensile strength (σt) 55-75 Mpa
Exploding CD’s
Mythbusters:> 23,000 rpm CD will shatterScratches or defects are the culprit
52X drive -MAX: 27,500 rpm typical: 11,000 rpm
10,000 RPM = 65 m/s = 145 mph7200 gravities of accelerationAnd approx. 5 MPa stressYield Strength 60 MPa
Nalgene
Polycarbonate Properties
Density: 1.2 g/cc
Young's modulus (E) 2-2.4 Gpa
Tensile strength (σt) 55-75 Mpa
Elongation (ε) @ break 80-150%
Glass transition (Tg) 150 °C
Melting (Tm) 267 °C
Upper working temperature 115-130 °C
$7.3-11/kg
Bisphenol and Endocrine System
100-250 g bisphenol per Liter water in water bottles20 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 Science-Based Guidelines for Laboratory Animal Care, National Academies Press, Washington DC, 65-69, 2004.
Immune systemAntioxidant enzymesDecreases plasma testosteroneLearning 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)
