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Keywords. Derive from title Multiple word “keywords” e.g. polysilsesquioxane low earth orbit Brain storm synonyms Without focus = too many unrelated hits If you haven’t already, get it to me today. Research paper topics. 3D Stereolithography with polymers - PowerPoint PPT Presentation
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Keywords
• Derive from title
• Multiple word “keywords”
• e.g. polysilsesquioxane low earth orbit
• Brain storm synonyms
• Without focus = too many unrelated hits
• If you haven’t already, get it to me today.
Research paper topics• 3D Stereolithography with polymers• Plastic concrete – preparation, properties & applications.• Biocompatibility of silicones• Teflon and fluoropolymers –from Heaven or Hell?• Piezoelectric polymers- how they are made, why they are piezoelectric , and
applications.• Plastic in the oceans. How long do plastics last and where do they end up?• Plastic hermetic seals• Gas separation membranes through phase inversion• Thermally induced phase separation of polymeric foams.• The strongest plastic• Major catastrophe(s) due to a polymer• Replacing ivory with plastic (comparison of composition, structure and properties)• Plastic explosives and rocket fuels
•Polymers from soybeans•Furan based polymers from corn•Bacterial and fungal attack on polymers•Conducting polymers, new metallic materials•Semiconducting polymers for PV •Semiconducting polymers for OLED’s•Polymers for stealth •Polymers for fire protection•Smart polymers that change properties with external stimuli•Reworkable, healable or removable polymers•Photoresists
Homework
• Name files with your last name, and HWK#
• Within file, your name, HWK title, descriptive information (like the title of you paper topic)
-Never make your audience work
Bibliography homework
• Due on 27th at 11:59 PM• Based on your keyword search• J. Am. Chem. Soc. format with title
e.g. Doe, J., Smith, J. “Proper bibliographies for Professor Loy’s class,” J. Obsc. Academ. B. S. 2012, 1, 234.
Recommend endnote or pages or biblio.
Pseudoscience
An established body of knowledge which masquerades as science in an attempt to claim a legitimacy which it would not otherwise be able to achieve on its own terms; it is often known as fringe- or alternative science. The most important of its defects is usually the lack of the carefully controlled and thoughtfully interpreted experiments which provide the foundation of the natural sciences and which contribute to their advancement.
Johathan Hope: Theodorus' Spiral (2003)
Examples of pseudoscience:Intelligent design, polywater, cold fusion, N-rays,
Creationism, holistic medicine, etc…
Detecting Baloney
1. The discoverer pitches the claim directly to the media.• No peer review or testing of claims is possible
2. The discoverer says that a powerful establishment is trying to suppress his or her work.
3. The scientific effect involved is always at the very limit of detection.
• At signal noise & no one else can replicate• Requires unique instrumentation or experience
4. Evidence for a discovery is anecdotal.5. The discoverer says a belief is credible because it has endured
for centuries. 6. The discoverer has worked in isolation.7. The discoverer must propose new laws of nature to explain an
observation.
Polymer Phase Diagrams
Solid: amorphous glass (below glass trans) or crystalline& Liquid (above melting point)
Polymer Tacticity: Stereochemical configuration• typical for addition or chain growth polymers• not for typical condensation or step growth polymers
Me Me Me MeH H H HH H H HMe Me Me Me Me
H
Me Me H HH H Me Me MeH Me Me Me HH H H Me MeH
atactic
isotactic syndiotactic
MeO
OMe
n
Polymer Tacticity: Polymethylmethacrylate (PMMA)
Free radical - atacticAnionic - isotactic
Me Me Me MeO
O O OOOOO
MeMe Me Me
Me Me Me MeO
O O OOOOO
MeMe Me Me
Me
O
Me
O
isotactic syndiotactic
Why is this important?• Tacticity affects the physical properties
– Atactic polymers will generally be amorphous, soft, flexible materials
– Isotactic and syndiotactic polymers will be more crystalline, thus harder and less flexible
• Polypropylene (PP) is a good example– Atactic PP is a low melting, gooey material– Isoatactic PP is high melting (176º), crystalline,
tough material that is industrially useful– Syndiotactic PP has similar properties, but is
very clear. It is harder to synthesize
Step Growth Configurations
HN
O
HN 12
3
4
5
6
OHN
O
NH
O
HN
O n
Nylon-6
Step Growth Configurations
HN
NH
O
O1
2
3
4
5
6
NH O
O
NH
NH
1
O
2
3
4
56
O
HN
HNO
NH
O
NH
HN
O
O n
Nylon 6,6
mp 265 °Ctg 50 °C
Chapter 2: Synthesis of Polymers
1) Step Growth
2) Chain Growth
Two major classes of polymerization mechanisms
Step Growth Polymerization: Condensation
HO2C CO2H
HOOH
terephthalic acid
ethylene glycol
O
O O
O
n
1:1 monomer ratio
Poly(ethylene terephthalate)or PET or PETE = polyester
Two equivalents of water is lost or condensed for each equivalent of monomers
Dacron if a fiber
Step Growth Polymerization: Condensation
HO2C CO2H
HOOH
terephthalic acid
ethylene glycol
O
HO O
OOH
O
HO O
OOH
HOOH
O
O O
OOH
HO
-H2O
-H2O
Biaxially stretched PETE is “Mylar”
Step growth systems• Epoxies• Polyurethanes & ureas• Nylon & polyesters• Kevlar• Polyaryl ethers (PEEK)• Polysulphones• Polyimides• Polythiophenes & Photovoltaic polymers• Polysulfides and polyphenyl ether
H2NR NH2
R'
O
Cl
O
Cl
AA BB
Mechanics of Step Growth: • Many monomers• All are reactive
Each has functionality of 2;Can make two bonds
R'
O
O
NH
R
HN
nLinear, soluble Nylon polymer
Mole fraction Conversion = 1 – [COCl]/[COCl]0
Mechanics of Step Growth:
NH2
R
H2N
R'
O
Cl
O
Cl
H2NR
NH2
H2NR NH2
NH2
R
H2N
H2N R NH2
H2N R NH2
H2N
R
NH2
H2NR
NH2
R'
O
Cl
O
Cl
R'
O
Cl
O
Cl
R'
O
Cl
O
Cl
R'
O
Cl
O
ClR'
O
Cl
O
Cl
R'
O
Cl
O
Cl
R'
O
Cl
O
Cl
R'
O
Cl
O
Cl
H2NR
NH2
H2N
R
NH2
R'
O
Cl
O
Cl
NH2
R
H2N
H2N R NH2
H2NR
NH2
R'
O
Cl
O
ClR'
O
Cl
O
Cl
R'
O
Cl
O
Cl
H2NR
NH2
R'
O
Cl
O
Cl
NH2R
H2N
R'
O
Cl
O
Cl
NH2
R
H2N
R'
O
Cl
O
Cl
H2NR
NH2
R' O
Cl
O
Cl
34 COCl groups; p = 1 - [COCl]/[COCl]0 = 0 conversion
Mechanics of Step Growth: Monomer & Dimers
NH2
R
H2N
R'
O
Cl
O
Cl
H2NR
NH2
H2NR NH2
NH2
R
HN
H2N R NH
H2N R NH2
H2N
R
NH2
H2NR
NH2
R'
O
Cl
O
Cl
R'
O
Cl
O
Cl
R'
O
O
Cl
R'
O
Cl
O
ClR'
O
Cl
O
Cl
R'
O
Cl
O
Cl
R'
O
O
Cl
R'
O
Cl
O
Cl
H2NR
NH2
H2N
R
NH2
R'
O
Cl
O
Cl
NH2
R
HN
H2N R NH2
H2NR
NH2
R'
O
Cl
O
ClR'
O
Cl
O
Cl
R'
O
O
Cl
H2NR
NH2
R'
O
Cl
O
Cl
NH2R
H2N
R'
O
Cl
O
Cl
NH2
R
H2N
R'
O
Cl
O
Cl
H2NR
NH
R' OO
Cl
30 reactive groups p = 1 - [COCl]/[COCl]0 = 1-30/34 = 0.11
NH
R
HN
R'
O
O
H2NR
NH2
HNR
NH2
NHR
HN
H2N R NH
HN R NH2
H2N
R
NH
H2NR
NH2
R'O
Cl
O
R'
O
Cl
O
Cl
R'
O
O
Cl
R'O
O R'
O
Cl
O
R'
O
O
Cl
R'
O
O
Cl
R'
O
O Cl
H2NR
NH2
H2N
R
HN
R'OO
Cl
NH2
R
HN
H2N RHN
HNR
NH2
R'
O
Cl
O
Cl
R'
O
O Cl
R'
O
O
Cl
HNR
NH2
R'
O
Cl
O
Cl
NH2R
H2N
R'
O
O
Cl
NH2
R
HN
R'
O
Cl
O
Cl
H2NR
NH
R' OO
Cl
Mechanics of Step Growth: Monomer & Dimers & Trimers
19 reactive groups p = 1 - [COCl]/[COCl]0 = 1-19/34 = 0.44
Mechanics of Step Growth: Monomer, Dimers, Trimers, & Tetramers
13 reactive groups p = 1 - [COCl]/[COCl]0 = 1-13/34 = 0.62
NH
R
HN
R'
O
O
HN
RNH2
HNR NH2
NHR
HN
H2N R NH
HN R NH2
H2N
R
NH
H2NR
NH2
R'O
Cl
O
R'
O
Cl
O
Cl
R'
O
O
Cl
R'O
O
R'
O
Cl
O
R'
O
O
Cl
R'
O
O
R'
O
O
H2NR
NH2
H2N
R
HN
R'OO
Cl
NH2
R
HN
H2N RHN
HNR
NH
R'O
Cl
O
R'
O
O Cl
R'
O
O
HNR
NH
R'
O
Cl
O
NH2R
NH
R'
O
O
Cl
HN
R
HN
R'
O
O Cl
HNR
NH
R' OO
Cl
7 reactive groups p = 1 - [COCl]/[COCl]0 = 1-7/34 = 0.80
NH
R
HN
R'
O
O
HN
RNH2
HNR
NHNHR
HN
H2NR
HN
HN R NH2
H2N
R
NH
HN
R
NH2
R'OO
R'
O
O
Cl
R'
O
OR'
OO
R'
O
O
R'
O
O
Cl
R'
O
O
R'
O
O
NHR
NH
H2N
R
HN
R'OO
NH2
R
HN
HNR
NH
HNR
NH
R'O
Cl
O
R'O
O
ClR'
O
O
HNR
NH
R'
O
Cl
O
NH
RNH
R'
O
O
NH
R
NH
R'
O
OCl
HNR
HN
R'
O
O Cl
Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher
3 reactive groups p = 1 - [COCl]/[COCl]0 = 1-3/34 = 0.91
Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher
NH
RHN
R'
O
O
HNR
NH
HNR
NH
HNR
HN
H2NR
HN
HN RNH
H2N
R
NH
NH
R NH2
R'
O
O
R'
O
O
R'
O
O
R'O
O R'
O
O
R'
O
OCl
R'O
O
R'
O
O
NHR
NH
HN
R
HN
R'OO
HN
RNH
HN
RNH
HNR
NH
R'O
O
R'
O
O
R'
O
O
HNR
NH
R'
O
O
NH
RNH
R'
O
O
NH
R
NH
R'
O
OCl
RNH
R'
O
OCl
1 reactive groups p = 1 - [COCl]/[COCl]0 = 1-1/34 = 0.97
Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher
NHRHN
R'
O
O
HN
R
NH
HNR
NH
HNR
NH
HNR
HN
HNR
H2N
R
NH
NH
R
NH
R'
O
O
R'
O
O
R'
O
O
R'O
O
R'
O
O
R'
O
OCl
R'
O
O
R'
O
O
NHR
NH
HN
R
HN
R'OO
HN
RNH
HN
RNH
HN R NH
R'
O
O
R'
O
O
R'
O
O
HNR
NH
R'
O
O
NH
RNH
R'
O
O
NH
R
NH
R'
O
O
RNH
R'
O
O
1 reactive groups p = 1 - [COCl]/[COCl]0 = 1-1/34 = 0.97
Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher
NHRHN
R'
O
O
HN
R
NH
HNR
NH
HNR
NH
HNR
HN
HNR
H2N
R
NH
NH
R
NH
R'
O
O
R'
O
O
R'
O
O
R'O
O
R'
O
O
R'
O
OCl
R'
O
O
R'
O
O
NHR
NH
HN
R
HN
R'OO
HN
RNH
HN
RNH
HN R NH
R'
O
O
R'
O
O
R'
O
O
HNR
NH
R'
O
O
NH
RNH
R'
O
O
NH
R
NH
R'
O
O
RNH
R'
O
O
If R = R’ = Phenylene = KevlarMw = 4014 g/mol
Step-Growth Polymerization• Because high polymer does not form until the end of the
reaction, high molecular weight polymer is not obtained unless high conversion of monomer is achieved.
€
Xn =1
1− p
Xn = Degree of polymerizationp = mole fraction monomer conversion
1
10
100
1000
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Mole Fraction Conversion (p)
Degree of Polymerization
Degree of Polymerization for step growth polymers
X = [COCl]0/[COCl] = 1/1-p
X or DP = 1/(1-p) = 1/1-0.97 = 1/0.03 = 33
Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher
NHRHN
R'
O
O
HN
R
NH
HNR
NH
HNR
NH
HNR
HN
HNR
H2N
R
NH
NH
R
NH
R'
O
O
R'
O
O
R'
O
O
R'O
O
R'
O
O
R'
O
OCl
R'
O
O
R'
O
O
NHR
NH
HN
R
HN
R'OO
HN
RNH
HN
RNH
HN R NH
R'
O
O
R'
O
O
R'
O
O
HNR
NH
R'
O
O
NH
RNH
R'
O
O
NH
R
NH
R'
O
O
RNH
R'
O
O
If R = R’ = Phenylene = KevlarMw = 4014 g/mol
Impact of percent reaction, p, on DP
if p = DP =
0.5 2
0.7 3.3
0.9 10
0.95 20
0.99 100
0.999 1000
Degree of Polymerization, D.P. = No / N = 1 / (1 - p)Assuming perfect stoichiometry
DPmax= (1 + r) / (1 - r) where r molar ratio of reactants
if r = [Diacid] / [diol] = 0.99, then DPmax= 199
Effect of Extent of reaction on Number distribution
Effect of Extent of reaction on weight distribution
Problems in Achieving High D. P.
1. Non-equivalence of functional groups
a. Monomer impurities1. Inert impurities (adjust stoichiometry)2. Monofunctional units terminate chain
b. Loss of end groups by degradation
c. Loss of end groups by side reactions with media
d. Physical losses e. Non-equivalent reactivity
f. Cyclization
. Unfavorable Equilibrium Constant
Impact of Thermodynamics
• Esters from Acids and alcohols Keq = 1-10
• Amides from Acids and amines Keq = 10-1000
• Amides or esters from acid chlorides, Keq >104
Interfacial Polymerization: Nylon Rope trick
Diamine, NaOH, in H2O
Adipoyl chloridein hexane
Nylon 6,6
Driving Reactions forward with physics
O
Cl
O
ClH2N
NH2
hexane-1,6-diaminehexanedioyl dichloride
or adipoyl chloride
O
O
HNNH n
Biaxially stretched PETE is “Mylar”
Tg = 70 °CTm = 265 °C
O
O O
O
n
OO
O
O n
Tg < 0 °CTm = 50 °C
O
HO O
OOH
O
O O
O
HO
O
HO O
OOH
-H2O
O
OH
OO
Step Growth Polymerization: Condensation
Each reaction occurs at approximately the same rate.Any monomer or growing oligomer can participate
O
HO
O
O O
O
HO
O
HO O
OOH
-H2O
OO
Step Growth Polymerization: Condensation
Impurities will kill growth and limit molecular weightDelayed commercialization of condensation polymers
Dr. Wallace Hume CaruthersHead of DuPont Organic research Labs50 patents
NylonPolyesterPolychoroprene (Neoprene)
The Guy who got the ball rolling
More Step Growth (Condensation) Polymers & their monomers
HO2C CO2H
terephthalic acid
diaminobenzene
O
NH O
HN
n
Kevlar
NH2H2N
Tg = NATm = 500 °C
Nomex and Technora
Twaron (AKZO)Stephanie Louise Kwolek (DuPont)
Polyaramides
O
HN
HN
On
Polyamides via Condensation -- Nylon 66
C-(CH2)4-C
OO
OOH
H
CH2-(CH2)4
-CH2 NH2NH2
+
slight excess
C-(CH2)4-C
OO
O- O-
(CH2)4
CH2 CH2
NH3+ NH3
+
Nylon Salt
60% Slurry
200 C, 15 Atm. 1 hr
NH3+(CH2)6
-NH-C-(CH2)4-C-NH-(CH2)6
-NH-C-(CH2)4-C
O
OO
OO-
8-10
270-300 C, 1hr
- H2O
NH-(CH2)6-NH-C-(CH2)4
-C
O
O
Nylon 6 6
mp. 265C, Tg 50C, MW 12-15,000Unoriented elongation 780%
More Step Growth (Condensation) Polymers & their monomers
Tg = 150 °CTm = 267 °C
Me
Me
HO OH
Cl Cl
O
Bisphenol A
phosgene
Me
Me
O O
O
n
PolycarbonateLexan
Two phase: interfacial polymerization
More Step Growth (Condensation) Polymers & their monomers
Tg = 200 °C; Films pressed at 250 °CUse temperature < 175 °CStable in air to 500 °CSelf-extinguishing
Me
Me
O O
S ClClO
O
Me
Me
O O S
O
O n
Na
Na
-2n NaCl
Polysulfone
Mw = 60-250K
More Step Growth (Non-condensation) Polymers & their monomers
ONC CNO
n
PolyurethaneHO OH
HN
HN
OO
O O
isocyanates
Polyphenylene Oxide (PPO)
R1
R2
OH + n/2 O2
R1
R2
O O
R2
R1
+ n H2O
cat
cat =
NN
CH3
CH3N
CH3
CH3
3 : 1
or
10:1
Cu+
Amine Complex
Noryl is a blend with polystyrene
Oxidative Coupling Process
Mn 30,000 to 120,000Amorphous , Tg 210C Crystalline, Tm 270CBrittle point -170CThermally Stable to 370C
Step Growth Polymers
• Polyesters, polyamides, engineering plastics such as polysulfones, polyetherether ketones (PEEK), polyurethanes.
• Condensation often occurs.
• Polymerization affords high MW late in the game
Me
NCO
HO OH
OCNMe
NH
NH
O
O
O
On
Step-GrowthNon-Condensation Polymerization
Polyurethanes
1,4-toluenediisocyanate + 1,3-propanediol
[RCO2]2SnBu2
OCN
OCN
NCO
HO OH
OH
NH
HN
NH
O
O
O
OO
O
O O
O
O
NH
HN
NH
O O
O
O O
O
1 1
Functionalities > 2: Crosslinking into networks
f = 3
Polyurethanes(thermoset)
Thermosets
• Urethanes
• Epoxies
• Polyesters (2-stage)
• Formaldehyde-aromatic
• Melamine-formaldehyde
Generally: Start as low viscosity liquids (low Mw)And set or cure to form glassy “vitrified” solids.
Gelation: f > 2
• If f > 2
• No cyclics form
then an infinite network is possible
(unless it phase separates!!!)
f = 3f = 4
f = 4
f = 3
f = 4 f = 6
f = 6
f = 4 f = 8
f = 8 f = 8 f = 14
Functionality Higher than Two
Phase separation = gels, glasses, or precipitates
Due to chemical bonding
Functionality = Two: Linear polymers
f = 2f = 2
f = 2
f = 2
f = 2 f = 2
Physical gels may form due to poor solubility of polymer
Functionality = Three: Cyclization
Lowers functionality & delays (or even prevents) gelation
f - 14 f = 8
Gel point = 1/(f -1) = 1/2 or 50% conversionIf cyclics present, gel point is higher.
Addition Polymerizations
R Rn
1) Catalyzed polymerization free radicalcationicanioniccoordination
2) Active group on end of polymer3) MW increases more rapidly4) Cheap & easier than step growth5) Enthalpically favorable
Free Radical Polymerizations
• Initiators (catalyst): – Thermal: azo compounds, peroxides, – Redox: persulfates– Photochemical: azo, peroxides,
amine/ketone mixtures
• Monomers
R R
R
R
R
RR
R
R
RR
R
R
R
Usually polymerize
Almost never polymerize
Polymerize fine Almost never polymerize
Seldom polymerize
Free radical Mechanism
Initiation: N
NNC
NC
Δ
NC CN
N2
or hν
Ea = 140 – 160 kJ mol-1
Kd = 8 x 10-5 s-1
t1/2 = 10 h at 64 °C
Propagation:
RR
NCkp
R
CN
R
Termination:
R
CN
R R
NC
R R
CN
R
R
NC
R
R
CN
R R
NC
R R
CN
R
R
NC
R
H
H
]M][•M[kR pp =
kp = 102 - 104 L/mol s
kt = 106 - 108 L/mol s
2tt ]•M[k2R =
Free Radical Polymerization Kinetics
MW
TIME
•MOST POLYMERS FORM IN SECONDS OR LESS• POLYMERIZATIONS TAKE HRS
Rp [M]; R∝ p [I]∝ 1/2
Living Radical Polymerizations:
1) Atom TransfeR Polymerization (ATRP)2) Polymerization (RAFT)3) TEMPO
MW increases linearly with timeNarrow Mw distributionsBlock copolymers
Lower concentration of propagating species Lower termination rate
Cationic Polymerizations:
R
cat
R
cat Rcat
R R
catR R
catR R
-H+
R = OR, NR2, Ph, vinyl, alkyl
H+O OH
O
HO OO n
Ring opening polymerization
Vinyl polymerization
Anionic Polymerizations:
R Rn
R = Ph, vinyl, CO2R, CN
Rn
nR
R
H, Me,
cat
cat
cat = Alkyl or aryl Lithium, sodium naphalide, alkyl Grignard, some alkoxides
Vinyl polymers
Diene polymers
Anionic Polymerizations:
OR
HO
Rn
cat.
R = H, Alkyl
O
R
cat
R = H, MeO
Rn
Polyacetals or carbonyls
Poly ethers
Anionic Polymerizations:
Si
OSi O
Si
OSiO
MeMe
Me
Me
MeMeMe
Me SiO
SiO
SiO
SiO
Me Me Me MeMe MeMe Me
n
Alkoxides
Polysiloxanes
Coordination Polymerizations:
Transition Metal Mediated Polymerizations-Ziegler Natta polymerizations (Early TM)-ring opening metathesis polymerization (metal Alkylidenes)-Insertion polymerizations (mid to late TM’s)
Ziegler Natta Polymerizations
• ZN are heterogeneous; solid catalysts• Catalytic polymerizations• Early TM halide, AlR3 on MgCl2• Polypropylene and HDPE• Highly productive: 106g polymer/gram
catalyst-hour• 10,000 turn overs/second (enzyme like
speed)-diffusion limited• Stereochemical control:
RR
nTiCl4, AlMe3
Karl Ziegler (1898-1973)
Giulio Natta (1903-1979)iso or syndiotactic polymers
Ziegler Natta Monomers
R
α-olefinsstyrenes
R
R = alkyl, aryl
Not compatible with heteroatoms (O,N,S,etc)
Polymers Synthesized with Complex Coordination Catalysts
Plastics• Polyethylene, high
density (HDPE)
• Polypropylene, isotactic
• Polystyrene, syndiotactic
Bottles, drums, pipes, sheet, film, etc.
Automobile and appliance parts, rope, carpeting
Specialty plastics
Ring Opening Metathesis
• Strained Rings with C=C bonds
• Metal alkylidene catalysts– Ti, Mo, W alkylidenes (Schrock catalysts)– Ruthenium alkylidenes (Grubbs catalysts)
• Living polymerizations
Ru
PCy3
Ph
NN
ClCl
n
Examples of ROMP
Me
No Reaction
R
Rn
R ≠ OH, NH, CO2H,
No strain, no polymer
n
OO
n
Acyclic Diene Metathesis Polymerization
R
Schrock or Grubbs catalyst
-CH2=CH2
Rn
Coordination-Condensation polymerizationEthylene gas is producedNot commerciallized
Redox Polymerizations
HN
anodic oxidativepolymerization
HN
n
HN
HN
n
[O]HN N
H
N
H
N
H
N
HH
H
N
H
N
HH
H
-2H+ N
H
N
H
Polypyrrole
Redox Polymerizations
-2H+
NH2 NH2 NH2 N NH2
H
H
H
N NH2
H
N NH2
H
n
Polyaniline
When acid doped: conducting polymer
Polymerization Techniques
• Bulk-no solvent just monomer + catalysts
• Solution Polymerization-in solvent
• Suspension-micron-millimeter spheres
• Emulsion-ultrasmall spheres
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
Plasma Polymerization
Characterization of Polymers
• 1H & 13C Nuclear Magnetic Resonance spectroscopy (NMR)
• Infrared spectroscopy (Fourier Transform IR)
• Elemental or combustion analyses
• Molecular weight
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)
