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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

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Keywords

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

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


Keywords

  • 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

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

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.


Keywords

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

Detecting Baloney

  • The discoverer pitches the claim directly to the media.

    • No peer review or testing of claims is possible

  • The discoverer says that a powerful establishment is trying to suppress his or her work.

  • 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

  • Evidence for a discovery is anecdotal.

  • The discoverer says a belief is credible because it has endured for centuries.

  • The discoverer has worked in isolation.

  • The discoverer must propose new laws of nature to explain an observation.


Keywords

Polymer Phase Diagrams

Solid: amorphous glass (below glass trans) or crystalline

& Liquid (above melting point)


Keywords

Polymer Tacticity: Stereochemical configuration

• typical for addition or chain growth polymers

• not for typical condensation or step growth polymers


Keywords

Polymer Tacticity: Polymethylmethacrylate (PMMA)

Free radical - atactic

Anionic - isotactic

isotactic

syndiotactic


Why is this important

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


Keywords

Step Growth Configurations


Keywords

Step Growth Configurations


Chapter 2 synthesis of polymers

Chapter 2: Synthesis of Polymers

Two major classes of polymerization mechanisms

1) Step Growth

2) Chain Growth


Step growth polymerization condensation

Step Growth Polymerization: Condensation

Poly(ethylene terephthalate)

or PET or PETE = polyester

Two equivalents of water is lost or condensed for each equivalent of monomers


Keywords

Dacron if a fiber


Step growth polymerization condensation1

Step Growth Polymerization: Condensation

Biaxially stretched PETE is “Mylar”


Step growth systems

Step growth systems

  • Epoxies

  • Polyurethanes & ureas

  • Nylon & polyesters

  • Kevlar

  • Polyaryl ethers (PEEK)

  • Polysulphones

  • Polyimides

  • Polythiophenes & Photovoltaic polymers

  • Polysulfides and polyphenyl ether


Keywords

Mechanics of Step Growth:

• Many monomers

• All are reactive

Mole fraction Conversion = 1 – [COCl]/[COCl]0

Each has functionality of 2;

Can make two bonds

Linear, soluble Nylon polymer


Keywords

Mechanics of Step Growth:

34 COCl groups; p = 1 - [COCl]/[COCl]0 = 0 conversion


Keywords

Mechanics of Step Growth: Monomer & Dimers

30 reactive groups p = 1 - [COCl]/[COCl]0 = 1-30/34 = 0.11


Keywords

Mechanics of Step Growth: Monomer & Dimers & Trimers

19 reactive groups p = 1 - [COCl]/[COCl]0 = 1-19/34 = 0.44


Keywords

Mechanics of Step Growth: Monomer, Dimers, Trimers, & Tetramers

13 reactive groups p = 1 - [COCl]/[COCl]0 = 1-13/34 = 0.62


Keywords

Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher

7 reactive groups p = 1 - [COCl]/[COCl]0 = 1-7/34 = 0.80


Keywords

Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher

3 reactive groups p = 1 - [COCl]/[COCl]0 = 1-3/34 = 0.91


Keywords

Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher

1 reactive groups p = 1 - [COCl]/[COCl]0 = 1-1/34 = 0.97


Keywords

Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher

If R = R’ = Phenylene = Kevlar

Mw = 4014 g/mol

1 reactive groups p = 1 - [COCl]/[COCl]0 = 1-1/34 = 0.97


Step growth polymerization

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 = Degree of polymerization

p = mole fraction monomer conversion


Keywords

Degree of Polymerization for step growth polymers

X = [COCl]0/[COCl] = 1/1-p


Keywords

Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher

If R = R’ = Phenylene = Kevlar

Mw = 4014 g/mol

X or DP = 1/(1-p) = 1/1-0.97 = 1/0.03 = 33


Impact of percent reaction p on dp

Impact of percent reaction, p, on DP

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


Keywords

Effect of Extent of reaction on Number distribution


Keywords

Effect of Extent of reaction on weight distribution


Problems in achieving high d p

Problems in Achieving High D. P.

1. Non-equivalence of functional groups

a. Monomer impurities

1. 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

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


Keywords

Interfacial Polymerization: Nylon Rope trick

Driving Reactions forward with physics


Keywords

Biaxially stretched PETE is “Mylar”

Tg = 70 °C

Tm = 265 °C

Tg < 0 °C

Tm = 50 °C


Step growth polymerization condensation2

Step Growth Polymerization: Condensation

Each reaction occurs at approximately the same rate.

Any monomer or growing oligomer can participate


Step growth polymerization condensation3

Step Growth Polymerization: Condensation

Impurities will kill growth and limit molecular weight

Delayed commercialization of condensation polymers


Keywords

The Guy who got the ball rolling

Nylon

Polyester

Polychoroprene (Neoprene)

Dr. Wallace Hume Caruthers

Head of DuPont Organic research Labs

50 patents


More step growth condensation polymers their monomers

More Step Growth (Condensation) Polymers & their monomers

Polyaramides

Tg = NA

Tm = 500 °C

Twaron (AKZO)

Stephanie Louise Kwolek (DuPont)

Nomex and Technora


Polyamides via condensation nylon 66

Polyamides via Condensation -- Nylon 66

mp. 265C, Tg 50C, MW 12-15,000

Unoriented elongation 780%


More step growth condensation polymers their monomers1

More Step Growth (Condensation) Polymers & their monomers

Tg = 150 °C

Tm = 267 °C

Two phase: interfacial polymerization


More step growth condensation polymers their monomers2

More Step Growth (Condensation) Polymers & their monomers

Mw = 60-250K

Tg = 200 °C; Films pressed at 250 °C

Use temperature < 175 °C

Stable in air to 500 °C

Self-extinguishing


More step growth non condensation polymers their monomers

More Step Growth (Non-condensation) Polymers & their monomers

isocyanates


Polyphenylene oxide ppo

Polyphenylene Oxide (PPO)

Oxidative Coupling Process

Mn 30,000 to 120,000

Amorphous , Tg  210C Crystalline, Tm  270C

Brittle point -170C

Thermally Stable to  370C

Noryl is a blend with polystyrene


Step growth polymers

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


Keywords

Step-Growth

Non-Condensation Polymerization

Polyurethanes

[RCO2]2SnBu2

1,4-toluenediisocyanate + 1,3-propanediol


Keywords

Functionalities > 2: Crosslinking into networks

Polyurethanes

(thermoset)

f = 3


Thermosets

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

Gelation: f > 2

  • If f > 2

  • No cyclics form

    then an infinite network is possible

    (unless it phase separates!!!)


Keywords

Functionality Higher than Two

Phase separation = gels, glasses, or precipitates

Due to chemical bonding


Keywords

Functionality = Two: Linear polymers

Physical gels may form due to poor solubility of polymer


Keywords

Functionality = Three: Cyclization

Lowers functionality & delays (or even prevents) gelation

Gel point = 1/(f -1) = 1/2 or 50% conversion

If cyclics present, gel point is higher.


Addition polymerizations

Addition Polymerizations

1) Catalyzed polymerization

free radical

cationic

anionic

coordination

2) Active group on end of polymer

3) MW increases more rapidly

4) Cheap & easier than step growth

5) Enthalpically favorable


Free radical polymerizations

Free Radical Polymerizations

  • Initiators (catalyst):

    • Thermal: azo compounds, peroxides,

    • Redox: persulfates

    • Photochemical: azo, peroxides, amine/ketone mixtures

  • Monomers


Free radical mechanism

Free radical Mechanism

Initiation:

Ea = 140 – 160 kJ mol-1

Kd = 8 x 10-5 s-1

t1/2 = 10 h at 64 °C

Propagation:

kp = 102 - 104 L/mol s

Termination:

kt = 106 - 108 L/mol s


Free radical polymerization kinetics

Free Radical Polymerization Kinetics

Rp ∝ [M]; Rp ∝ [I]1/2

MW

•MOST POLYMERS FORM IN SECONDS OR LESS

• POLYMERIZATIONS TAKE HRS

TIME


Living radical polymerizations

Living Radical Polymerizations:

MW increases linearly with time

Narrow Mw distributions

Block copolymers

  • Atom TransfeR Polymerization (ATRP)

  • Polymerization (RAFT)

  • TEMPO

Lower concentration of propagating species

Lower termination rate


Cationic polymerizations

Cationic Polymerizations:

Vinyl polymerization

Ring opening polymerization


Anionic polymerizations

Anionic Polymerizations:


Anionic polymerizations1

Anionic Polymerizations:


Anionic polymerizations2

Anionic Polymerizations:


Coordination polymerizations

Coordination Polymerizations:

Transition Metal Mediated Polymerizations

-Ziegler Natta polymerizations (Early TM)

-ring opening metathesis polymerization (metal

Alkylidenes)

-Insertion polymerizations (mid to late TM’s)


Keywords

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:

Karl Ziegler (1898-1973)

iso or syndiotactic polymers

Giulio Natta (1903-1979)


Ziegler natta monomers

Ziegler Natta Monomers

Not compatible with heteroatoms (O,N,S,etc)


Polymers synthesized with complex coordination catalysts

Plastics

Polyethylene, high density (HDPE)

Polypropylene, isotactic

Polystyrene, syndiotactic

Polymers Synthesized with Complex Coordination Catalysts

Bottles, drums, pipes, sheet, film, etc.

Automobile and appliance parts, rope, carpeting

Specialty plastics


Ring opening metathesis

Ring Opening Metathesis

  • Strained Rings with C=C bonds

  • Metal alkylidene catalysts

    • Ti, Mo, W alkylidenes (Schrock catalysts)

    • Ruthenium alkylidenes (Grubbs catalysts)

  • Living polymerizations


Keywords

Examples of ROMP


Acyclic diene metathesis polymerization

Acyclic Diene Metathesis Polymerization

Coordination-Condensation polymerization

Ethylene gas is produced

Not commerciallized


Redox polymerizations

Redox Polymerizations

Polypyrrole


Redox polymerizations1

Redox Polymerizations

Polyaniline

When acid doped: conducting polymer


Polymerization techniques

Polymerization Techniques

  • Bulk-no solvent just monomer + catalysts

  • Solution Polymerization-in solvent

  • Suspension-micron-millimeter spheres

  • Emulsion-ultrasmall spheres


Less common polymerization techniques

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

Plasma Polymerization


Characterization of polymers

Characterization of Polymers

  • 1H & 13C Nuclear Magnetic Resonance spectroscopy (NMR)

  • Infrared spectroscopy (Fourier Transform IR)

  • Elemental or combustion analyses

  • Molecular weight


Polymerization techniques1

Polymerization Techniques

  • Bulk-no solvent just monomer + catalysts

  • Solution Polymerization-in solvent

  • Suspension-micron-millimeter spheres

  • Emulsion-ultrasmall spheres


Bulk polymerizations

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


Keywords

Storage of vinyl monomers in air = peroxide initiated polymerizations

Tankcar of styrene

2005 in Ohio


Solution polymerization

Solution Polymerization

• Better control of reaction temperature

• Better control of polymerization

• Slower

• Not very green-residual solvent


Suspension polymerization

Suspension Polymerization

  • Oil droplets dispersed in water

  • Initiator soluble in oil

  • Greener than solution polymerization

Filter off particles of polymer


Emulsion polymerization

Emulsion Polymerization

Still oil in water (or the reverse)

Initiator in water

Smaller particles (latex)

Excellent control of temp

Solution turns white

Polystyrene latex


Keywords

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 water

Initiator in water


Less common polymerization techniques1

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

Solid State Polymerizations

Heating Oligomeric Condensation Polymers

Tg < X < Tm

Tg = 67 °C and Tm = 265 °C

Nylons, Polyesters

Nylon 66 Tg = 70 °C and Tm = 264 °C


Solid state polymerizations1

Solid State Polymerizations

Topological Polymerizations: Polymerization of crystals

Quinodimethane polymerizations

Di- and Triacetylene polymerizations

In single crystals


Solid state polymerizations of fullerenes

Solid State Polymerizations of Fullerenes

Topological polymerization in 3-D


Gas phase polymerization

Gas Phase Polymerization

Light olefins

Parylenes


Light olefins

LIGHT OLEFINS

Ethylene and propylene

• Food Packaging

• Hygiene & Medical

• Consumer & Ind. Liners

• Stretch Films

• Agricultural Films

• HDSS

Film

2004 Global PE Demand: 136 Billion Pounds


Keywords

Types of Polyethylene

LLDPE (0.860-0.926)

“Linear Low Density”

HDPE (0.940-0.965)

“High Density”

O

O

O

C-OH

O

O

O

O

O

O

O

O

LDPE (0.915-0.930)

“Low Density”

High Pressure Copolymers

(AA, VA, MA, EA)


Gas phase polymerization light olefins

Gas Phase Polymerization: Light olefins

Oxygen initiator

2-3K atmospheres

250 °C


Gas phase polymerization light olefins1

Gas Phase Polymerization: Light olefins

Fluidized bed polymerization

MORE FLEXIBLE


Gas phase polymerization paralene

Gas Phase Polymerization: Paralene

Gas phase

Polymerizes on contact

Conformal coatings

Pinhole free

Preserving artifacts (paper)

Microelectronics

Medical devices


Plasma polymerization1

Plasma Polymerization

  • 500 Å - 1 micron thick films

  • Continuous coatings

  • Solvent free

  • High cohesion to surface

  • Highly cross-linked

  • Generally amorphous


Plasma polymerization2

Plasma Polymerization

Monomers: Hydrocarbons

Double or triple bonds nice, not necessary

Fluorocarbon

Tetraalkoxysilanes (for silica)


Plasma polymerization3

Plasma Polymerization

Fig 2. Tubular-type reactors

Fig1. Bell-jar type reactors

P- pumps; PS-power supply; S-substrate

M-feed gas inlet; G-vacuum gauge


Plasma polymerization4

Plasma Polymerization

PET [Poly(Ethylene Terephthalate)]

Multi-layer bottles

No loss of fizz


Characterization of polymers1

Characterization of Polymers

  • 1H & 13C Nuclear Magnetic Resonance spectroscopy (NMR)

  • Infrared spectroscopy (Fourier Transform IR)

  • Elemental or combustion analyses

  • Molecular weight


Keywords

13C NMR is a very powerful way to determine the microstructure of a polymer.

13C NMR spectrum of CH3 region of atactic polypropylene


Infrared spectroscopy bond vibrations

Infrared Spectroscopy: Bond vibrations

polystyrene

C=C-H

C=C

stretch

C-H

2-16 Micron wavelength range


Infrared spectroscopy bond vibrations1

Infrared Spectroscopy: Bond vibrations

C-H bend

C=O

C-O

C-H

stretch

Poly(methyl methacrylate)


Types of addition polymerizations

Types of Addition Polymerizations


Chemical modification of polymers

Chemical Modification of Polymers

Hydrolysis

2) Oxidation

3) Photochemistry

(can be oxidation or not)

4) Chemical crosslinking

5) Chemical modification

See next slide


Keywords

Chemical Modification of Polyvinyl Alcohol to make Polyvinyl butyral for safety glass

No PVB

With PVB


Keywords

Bullet Proof Glass


Keywords

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.


Keywords

Polycarbonate is

Strong Material

Young's modulus (E) 2-2.4 Gpa

Tensile strength (σt) 55-75 Mpa


Exploding cd s

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


Keywords

Nalgene


Polycarbonate properties

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


Keywords

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 Science-Based 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

Nalgene Substitutes-food and water

  • Glass (blender, pitchers, glasses)

  • Metal (water bottles)

  • Polyethylene (water bottles)

  • Polyamide or Nylon (baby bottles)


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