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 27 th 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

Polymer Tacticity: Polymethylmethacrylate (PMMA) Free radical - atactic Anionic - isotactic isotacticsyndiotactic

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

Chapter 2: Synthesis of Polymers 1) Step Growth 2) Chain Growth Two major classes of polymerization mechanisms

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

Dacron if a fiber

Step Growth Polymerization: Condensation 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

Mechanics of Step Growth: Many monomers All are reactive Each has functionality of 2; Can make two bonds Linear, soluble Nylon polymer Mole fraction Conversion = 1 – [COCl]/[COCl] 0

Mechanics of Step Growth: 34 COCl groups; p = 1 - [COCl]/[COCl] 0 = 0 conversion

Mechanics of Step Growth: Monomer & Dimers 30 reactive groups p = 1 - [COCl]/[COCl] 0 = 1-30/34 = 0.11

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

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

1 reactive groups p = 1 - [COCl]/[COCl] 0 = 1-1/34 = 0.97 Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher

1 reactive groups p = 1 - [COCl]/[COCl] 0 = 1-1/34 = 0.97 Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher If R = R’ = Phenylene = Kevlar Mw = 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. X n = Degree of polymerization p = mole fraction monomer conversion

Degree of Polymerization for step growth polymers X = [COCl] 0 /[COCl] = 1/1-p

X or DP = 1/(1-p) = 1/ = 1/0.03 = 33 Mechanics of Step Growth: Monomer, Dimers, Trimers, Tetramers & Higher If R = R’ = Phenylene = Kevlar Mw = 4014 g/mol

Impact of percent reaction, p, on DP if p =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

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 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 lossese. Non-equivalent reactivity f. Cyclization. Unfavorable Equilibrium Constant

Impact of Thermodynamics Esters from Acids and alcohols K eq = 1-10 Amides from Acids and amines K eq = Amides or esters from acid chlorides, K eq >10 4

Interfacial Polymerization: Nylon Rope trick Driving Reactions forward with physics

Biaxially stretched PETE is “Mylar” T g = 70 °C T m = 265 °C T g < 0 °C T m = 50 °C

Step Growth Polymerization: Condensation Each reaction occurs at approximately the same rate. Any monomer or growing oligomer can participate

Step Growth Polymerization: Condensation Impurities will kill growth and limit molecular weight Delayed commercialization of condensation polymers

Dr. Wallace Hume Caruthers Head of DuPont Organic research Labs 50 patents Nylon Polyester Polychoroprene (Neoprene) The Guy who got the ball rolling

More Step Growth (Condensation) Polymers & their monomers T g = NA T m = 500 °C Nomex and Technora Twaron (AKZO) Stephanie Louise Kwolek (DuPont) Polyaramides

Polyamides via Condensation -- Nylon 66 mp. 265C, Tg 50C, MW 12-15,000 Unoriented elongation 780%

More Step Growth (Condensation) Polymers & their monomers T g = 150 °C T m = 267 °C Two phase: interfacial polymerization

More Step Growth (Condensation) Polymers & their monomers T g = 200 °C; Films pressed at 250 °C Use temperature < 175 °C Stable in air to 500 °C Self-extinguishing Mw = K

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

Polyphenylene Oxide (PPO) Noryl is a blend with polystyrene 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

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

Step-Growth Non-Condensation Polymerization Polyurethanes 1,4-toluenediisocyanate + 1,3-propanediol [RCO 2 ] 2 SnBu 2

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!!!)

Functionality Higher than Two Phase separation = gels, glasses, or precipitates Due to chemica l bonding

Functionality = Two: Linear polymers Physical gels may form due to poor solubility of polymer

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 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 Initiators (catalyst): –Thermal: azo compounds, peroxides, –Redox: persulfates –Photochemical: azo, peroxides, amine/ketone mixtures Monomers

Free radical Mechanism Initiation: E a = 140 – 160 kJ mol -1 K d = 8 x s -1 t 1/2 = 10 h at 64 °C Propagation: Termination: k p = L/mol s k t = L/mol s

Free Radical Polymerization Kinetics MW TIME MOST POLYMERS FORM IN SECONDS OR LESS POLYMERIZATIONS TAKE HRS R p ∝ [M]; R p ∝ [I] 1/2

Living Radical Polymerizations: 1)Atom TransfeR Polymerization (ATRP) 2)Polymerization (RAFT) 3)TEMPO MW increases linearly with time Narrow Mw distributions Block copolymers Lower concentration of propagating species Lower termination rate

Cationic Polymerizations: Ring opening polymerization Vinyl polymerization

Anionic 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)

Ziegler Natta Polymerizations ZN are heterogeneous; solid catalysts Catalytic polymerizations Early TM halide, AlR 3 on MgCl 2 Polypropylene and HDPE Highly productive: 10 6 g polymer/gram catalyst-hour 10,000 turn overs/second (enzyme like speed)-diffusion limited Stereochemical control: Karl Ziegler ( ) Giulio Natta ( ) iso or syndiotactic polymers

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 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

Examples of ROMP

Acyclic Diene Metathesis Polymerization Coordination-Condensation polymerization Ethylene gas is produced Not commerciallized

Redox Polymerizations Polypyrrole

Redox Polymerizations 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 1 H & 13 C 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 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

SuspensionEmulsionMini-emulsionMicro-emulsion Monomer in oil Initiator in oilInitiator 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 T g < X < T m Nylons, Polyesters Nylon 66 T g = 70 °C and T m = 264 °C T g = 67 °C and T m = 265 °C

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 2004 Global PE Demand: 136 Billion Pounds Food Packaging Hygiene & Medical Consumer & Ind. Liners Stretch Films Agricultural Films HDSS Film

Types of Polyethylene O O O O O O O O O O C-OH O HDPE ( ) “High Density” LLDPE ( ) “Linear Low Density” LDPE ( ) “Low Density” 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)

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

PET [Poly(Ethylene Terephthalate)] Multi-layer bottles No loss of fizz

Characterization of Polymers 1 H & 13 C Nuclear Magnetic Resonance spectroscopy (NMR) Infrared spectroscopy (Fourier Transform IR) Elemental or combustion analyses Molecular weight

13 C NMR is a very powerful way to determine the microstructure of a polymer. 13 C NMR spectrum of CH 3 region of atactic polypropylene

Infrared Spectroscopy: Bond vibrations 2-16 Micron wavelength range polystyrene C=C-H C-H C=C stretch

Infrared Spectroscopy: Bond vibrations Poly(methyl methacrylate) C=O C-O C-H stretch C-H bend

Types of Addition Polymerizations

Chemical Modification of Polymers 1)Hydrolysis 2) Oxidation 3) Photochemistry (can be oxidation or not) 4) Chemical crosslinking 5) Chemical modification See next slide

Chemical Modification of Polyvinyl Alcohol to make Polyvinyl butyral for safety glass 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) Gpa Tensile strength (σt) 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: 1.2 g/cc Young's modulus (E) Gpa Tensile strength (σt) Mpa Elongation break % Glass transition (Tg) 150 °C Melting (Tm) 267 °C Upper working temperature °C $7.3-11/kg

Bisphenol and Endocrine System  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, 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: , 2005.

Nalgene Substitutes-food and water Glass (blender, pitchers, glasses) Metal (water bottles) Polyethylene (water bottles) Polyamide or Nylon (baby bottles)