Polymers, plastics & macromolecules
Plastic = Polymer + additives
Processability: Mechanical properties: Other:
Anti-oxidants Fillers Stabilizers Sulphur Weakeners - lubricants Colorants Fire retardants Blowing agents Nucleating agents
Macromolecule = well-defined large molecule (dendrimers) and/or a very well-defined polymer (proteins) Materials
gasses liquids solids
ceramics polymers metals
natural polymers synthetic polymers
polypeptides polysacharides polynucleotides thermoplast thermoset Nature’s use of polymers:
Polysacharides. Cellulose (wood, cotton) Starch (potatoes, corn) Chitin
Polypeptides. (Spider) Silk Enzymes Collagen Horn Ivory
Polynucleotides. DNA, RNA History of synthetic polymers
Goodyear: Natural rubber - Used for over 3,500 years.
Charles Goodyear
Natural rubber 1839
1800 1900 2000
D S
S S S S n History of synthetic polymers
ONO2 ONO2
ONO2 ONO2 O2NO O O2NO O O O O O O O2NO O O2NO ONO2 ONO2 ONO2 ONO2
Natural rubber 1839
1800 1900 2000
Parkesine 1862
Parkes: Parkesine (based on cellulose nitrate) – first colorful plastic.
Alexander Parkes History of synthetic polymers
Cellulose based plastics (nitrate, acetate, xanthate)
Charles Frederick Cross JohnEdward Wesley John Hyatt Bevan
Cellulose acetate, Rayon Natural rubber 1892 1839 Celluloid 1868
1800 1900 2000
Parkesine 1862
ONO2 ONO2 O2CMe O2CMe
ONO2 ONO2 O2NO O2CMe O O2NO O2CMe O MeCO2 O MeCO2 O O O O O O O O O O O2NO O O2NO O OMeCO2 O MeCO2 ONO2 ONO2 O2CMe O2CMe ONO2 ONO2 O O2CMe O2CMe History of synthetic polymers OH
OH OH
HO OH 'the material of a thousand uses'
OH
Cellulose acetate, Rayon Natural rubber 1892 1839 Celluloid 1868
1800 1900 2000
Parkesine Bakelite 1862 1907
Baekeland: Bakelite - First fully synthetic polymer.
Leo Hendrick Baekeland History of synthetic polymers RignaultSemon: (1835),Baumannplasticized polyvinylchloride (1872), Klatte (1913) polyvinylchloride
Henry Victor Rignault WaldoFriederich Semon Klatte Eugen Baumann
Cellulose acetate, Rayon Natural rubber 1892 1839 Celluloid PVC 1868 1913
1800 1900 2000
PVC Parkesine PVC Bakelite Plasticized PVC 1835 1862 1872 1907 1926
O
Cl Cl Cl Cl O
O
O Polystyrene - 1839: E. Simon - 1845: A.W. Hofmann, J.Blyth - 1912: I Ostromislenskii - 1922: Staudinger
Cellulose acetate, Rayon Definition of Polystyrene Natural rubber 1892 polymers E. Simon 1839 Celluloid PVC 1839 Polystyrene 1868 1913 Hofmann & Blyth 1845 1800 1900 2000
Polystyrene production PVC Parkesine PVC Bakelite Plasticized PVC ~ 1935 1835 1862 1872 1907 1926
Staudinger: Plastics defined as a chain molecule wherein the monomeric blocks are linked together by covalent bonds. So called polymers (poly meros = many parts)
Hermann Staudinger History of synthetic polymers Cl Cl Cl Cl D
Cl Cl n Cl Cl
Cl Cl
Cellulose acetate, Rayon Definition of Polystyrene Natural rubber 1892 polymers Neoprene E. Simon 1839 Celluloid PVC 1839 Polystyrene 1868 1913 1931 Hofmann & Blyth 1845 1800 1900 2000
Polystyrene production PVC Parkesine PVC Bakelite Plasticized PVC ~ 1935 1835 1862 1872 1907 1926
Carothers: neoprene.
Wallace Hume Carothers History of synthetic polymers Fawcett/Gibson: Low density polyethylene (LDPE).
Rigenald Gibson Eric Fawcett
Cellulose acetate, Rayon Definition of Polystyrene Natural rubber 1892 polymers Neoprene E. Simon 1839 Celluloid PVC 1839 Polystyrene 1868 1913 1931 Hofmann & Blyth LDPE 1845 1933 1800 1900 2000
Polystyrene production PVC Parkesine PVC Bakelite Plasticized PVC ~ 1935 1835 1862 1872 1907 1926 History of synthetic polymers
O H O N N N H O H
Cellulose acetate, Rayon Definition of Nylon 66 Polystyrene Natural rubber 1892 polymers 1935 Neoprene E. Simon 1839 Celluloid PVC 1839 Polystyrene 1868 1913 1931 Hofmann & Blyth LDPE 1845 1933 1800 1900 2000
Polystyrene production PVC Parkesine PVC Bakelite Plasticized PVC ~ 1935 1835 1862 1872 1907 1926
Carothers: nylon 66.
Wallace Hume Carothers History of synthetic polymers Schlack: Nylon 6 – Perlon (IG-Farben) Dickson & Whinfield: poly(ethylene terephtalate)
Paul Schlack J.T. Dickson J.R. Whinfield
Cellulose acetate, Rayon Definition of Nylon 66 Polystyrene Natural rubber 1892 polymers 1935 Neoprene E. Simon 1839 Celluloid PVC 1839 Polystyrene 1868 1913 1931 Hofmann & Blyth LDPE 1845 1933 1800 1900 2000
1938- 1943 - PTFE Polystyrene - Polyurethanes production - Nylon 6 PVC Parkesine PVC Bakelite Plasticized PVC ~ 1935 - PET -Silicones 1835 1862 1872 1907 1926 - ….. Bayer: Polyurethanes (IG-Farben, Bayer) Plunkett: Teflon (Du Pont)
Otto Bayer Roy J. Plunkett History of synthetic polymers Ziegler: High density polyethylene
Karl Ziegler
Cellulose acetate, Rayon Definition of Nylon 66 Polystyrene 1892 1935 Natural rubber polymers HDPE i-PP HDPE LLDPE E. Simon Celluloid PVC Neoprene 1839 1953 1954 Phillips Cat 1978 1839 Polystyrene 1868 1913 1931 Hofmann & Blyth LDPE 1958 1845 1933 1800 1900 2000
1938- 1943 - PTFE Polystyrene - Polyurethanes production - Nylon 6 PVC Parkesine PVC Bakelite Plasticized PVC ~ 1935 - PET -Silicones 1835 1862 1872 1907 1926 - ….. Natta: isotactic polypropylene
Giulio Natta PMMA
KevlarLLDPE
Plexiglas Velcro
Biodegradable Polymers
Polycarbonate Fleece Spandex Semiconducting Polymers Lycra Classification of polymers
Structure Thermal behavior Thermoplast Linear
Branched
Crosslinked OH Thermoset
OH OH
S HO OH S S S
OH Classification of polymers
Composition Polymerization method
homo polymer Stepgrowth proces Polycondensation (PET, PC, nylon 66) block copolymer
Alternating copolymer Chaingrowth process Radical polymerization (PVC, PS) cationic/anionic polymerization (polyisobutene, PAN) random copolymer Coordination polymerization (PE, PP) Ring opening polymerization (nylon 6, polylactides)
graft copolymer Classification of polymers
Chain atom configurations
Poly(cis-1,4-isoprene), ‘natural rubber’
Poly(trans-1,4-isoprene), ‘gutta-percha’
Tacticity
atactic isotactic syndiotactic Requirements for polymerization.
∆G = ∆GPolymer – ∆GMonomers S S S S S S S S S S S S ∆G = ∆H – T·∆S S S o T > 160 C Floor temperature ~ 160oC Mostly ∆H < 0 en ∆S < 0 ΔG‡
Only when ∆Go < 0 polymerization takes place. monomers And the activation energy shouldn’t be too high.
ΔGo
polymer Polymerization takes place only when T ·│∆S│ < │∆H│
When T ·│∆S│ = │∆H│ à Tc = ∆H/∆S is the ceiling temperature
Above the ceiling temperature (T ·│∆S│ > │∆H│) depolymerization takes place. Ceiling temperature.
K Mn-1 + M Mn
K = [Mn] / [Mn-1] [M] ≈ 1/ [M]
Equilibrium condition: ∆G = 0 ∆G = ∆Go + R·T·LnK = ∆Go + R·T·Ln(1/[M]) ∆Go = ∆Ho – T·∆So = R·T·Ln[M]
o o Tc = ∆H / (∆S + R·ln[Mc]) Tc mostly given for [M] = 1 mol/L
The ceiling temperature is dependent on the monomer concentration. Stepgrowth proces Mw - Polycondensation
Characteristics: • all present molecules react with one another during the entire reaction • usually no termination • degree of polymerization increases in time 0 100% • usually a small molecule is split off monomer consumption
O O O OH - n H O OH 2 + HO HO O O O n
H O OH - n H2O O N + H2N NH2 HO O N O n H O O - n HCl OH + O O Cl Cl
n O H O OH O C N N C O + HO N N O H
O n Chaingrowth process Mw Radical polymerization (PVC, PS) cationic/anionic polymerization (polyisobutene, PAN) Coordination polymerization (PE, PP) Ring opening polymerization (nylon 6, polylactides) 0 100% monomer consumption
R • R R• • n
Characteristics: • no splitting off of small molecules • polymerization by addition of monomers to a growing chain • initiation required • several termination mechanisms • growth between initiation and termination only for a few seconds • degree of polymerization decreases in time Radical polymerization.
O O O - CO2 Initiation. ½ • O O O •
X X Propagation. R• • + • R X X n
Termination. X X • R Combination of radicals 2 R R X X n n X X n
H H • Disproportionation R + R R + R • X X X X X X X X n m n m Chain transfer
To monomer X • X R + R + H • X X X X n n
To polymer - intermolecularly X H X • n R + R R + R • R X X X H X X X X X X X n m n m m Leads to long chain branching
• To polymer - intramolecularly
• • CH2 CH2 CH CH3 CH CH3
CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 Leads to short chain branching cationic polymerization
+ - - + - + H [MeOBF3] [ROBF3] [ROBF3] n
anionic polymerization
N N N N C C N C C C + - NH2 + - + - K K NH2 K NH2 n Coordination/insertion polymerization
CH3 CH3
[Ti]-CH3 [Ti]-CH3 [Ti] [Ti] n
O O P P [Pd] [Pd]
C O O O O [Zn] P O O O [Zn] P
O CO2 n
O
O O
n Ring opening polymerization
O O H H H+ N N Acid catalyzed H n
O
[Zn] OMe O O Metal catalyzed O (coordination polymerization) n O O O
[Zn] OMe O O O O n O
O O O [Al] OMe
n Molecular weight and molecular weight distribution.
n n = 10,000
n+1
In a polymer sample the chains hardly ever have the same length. They have an average length.
Exceptions are for example proteins. Number average molecular weight.
Number of chains with length i Ni Mole fraction ni = = Total number of chains ΣNi
Σni = 1
ΣNi·Mi Ni M = = ·M = Σn ·M n Σ ( ) i i i ΣNi ΣNi Weight average molecular weight.
Weight of chains with length i ni·Mi ni·Mi Weight fraction w = = = i Total weight of all chains Σni·Mi Mn
Σwi = 1
2 Σni·Mi Mw = Σwi·Mi = Σni·Mi
ΣNi·Mi Compare: Mn = Σni·Mi = ΣNi An example:
City Population Amsterdam 1,000,000
Groningen 200,000
Schiermonnikoog 1,000
Average population:
1/3 x 1,000,000 Mn = Σni·Mi 1/3 x 200,000 1/3 x 1,000
= 400,333
We can say that the average person lives in a city of about 400,000. An example:
Weighted average: This is an average that would account for the fact that a large city like Amsterdam holds a larger percentage of the total population of the three cities than Schiermonnikoog.
City Population Amsterdam 1,000,000
Groningen 200,000
Schiermonnikoog 1,000
Mw = Σwi·Mi 1,000,000 1,000,000 x 1,201,000 = 1,000,000 x 0.8326 = 832,600 200,000 200,000 x = 200,000 x 0.1665 = 33,300 1,201,000 1,000 x 1,000 = 1,000 x 0.0008 = 0.8 1,201,000 + 865,900.8
We can say that the average person lives in a city of about 866,000. Calculating Mn & Mw.
M1 = 100
M2 = 10
n1 = ½
n2 = ½
Mn = Σni·Mi = ½ · 100 + ½ · 10
= 50 + 5 = 55
n ·M w 1 1 1 = = ½ · 100 / 55 = 10/11 Mn n ·M w 2 2 2 = = ½ · 10 / 55 = 1/11 Mn
Mw = Σwi·Mi = 10/11 · 100 + 1/11 ·10
= 90.9 + 0.9 = 91.8 Calculating Mn & Mw.
M1 = 100
M2 = 10
n1 = 1/11
n2 = 10/11
Mn = Σni·Mi = 1/11 · 100 + 10/11 · 10 = 18.2
n ·M w 1 1 1 = = 1/11 · 100 / 18.2 = ½ Mn n ·M w 2 2 2 = = 10/11 · 10 / 18.2 = ½ Mn
Mw = Σwi·Mi = ½ · 100 + ½ ·10 = 50 + 5 = 55 M1 = 100
M2 = 10 ΣNi·Mi Σn ·M Mn = i i = n1 = 1/11 n2 = 10/11 ΣNi Mn = Σni·Mi = 1/11 · 100 + 10/11 · 10 = 18.2
n1·M1 w1 n ·M n ·M w /M = = 1/11 · 100 / 18.2 = ½ w i i i i i i M i = = ni = n n ·M w /M n ·M Σ i i Mn Σ i i w 2 2 2 = = 10/11 · 10 / 18.2 = ½ Mn
Mw = Σwi·Mi = ½ · 100 + ½ ·10 = 50 + 5 = 55 n ·M 2 Σ i i w ·M w ·M 1 1 Mw = Σ i i = z1 = = ½ · 100 / 55 = 10/11 Σni·Mi Mw
w2·M2 z2 = = ½ · 10 / 55 = 1/11 M w ·M n ·M z /M w z i i i i i i M = i = = wi = z Σzi·Mi = 10/11 · 100 + 1/11 ·10 = 91.8 Σwi·Mi Mw Σzi/Mi Mn
n ·M 3 Σ i i Nr of M = Σzi·Mi = z 2 Σni·Mi Chains Mw
Mz
Mw What determines the properties of a polymer?
hardness, softness, brittleness, toughness transparance, adhesion
Mw, MWD & topology composition functionality mocrostructure linear X homo polymer end-capped
X X telechelics substituted block copolymer
MWD=1 MWD>>1 X X X X X random copolymer functional branches atactic star polymeer X X X X X isotactic X X X X X X syndiotactic hyper branched graft copolymer hyper functionalized Effect of chain length. H H C H
H n n state use 1-4 gas energy (heater, stove) 5-24 Volatile to viscous liquid energy (car - plane- ship) 25-50 Brittle solid parafine (candles) 103-104 Elastic-tough solid buckets, bags >105 Very tough solid medical implants, fibres, bullet-proof vests As a comparison: polyethylene for bucket: spaghetti with a length of >100 meter
Polyethylene for medical implant: spaghetti with a length of ± 1 km Entanglements make a polymer strong. Above Mc, the viscosity increases dramatically with increasing molecular weight
for Mw
3.4
1
Mc log Mw
Entanglements increases the viscosity which hampers the processability. Effect of chain structure.
Lineair: Thermoplast
HDPE UHMWPE Branched: Elastomer
Cross-linked: thermoset LDPE LLPE Modifications - copolymers.
• acryl = poly-acrylonitrile-methylmethacrylate
C O C O O N N O x y z
• HIPS (high impact polystyrene) = poly-styrene-butadiene
Polystyrene matrix +
Poly(butadiene) spheres Block crack propagation Modifications - composits.
§ Blends en composits. - other polymers - glasfibres - hessian/hemp Plastic recycling
mechanic recycling - re-use - 'downcycling'
thermal depolymerization & hydrolytic depolymerization - feedstock recycling: yields different chemicals - chemical recycling (depolymerization): yields monomers
energy
landfill Re-use: Plastic recycling - mechanic recycling Down cycling:
Solvay’s Vinyloop process Plastic recycling - mechanic recycling Plastic recycling – mechanochemical recycling
HSM Technology (High Stress Mixer) – A new development in melting the tire Mountain. Plastic recycling - Chemical recycling Depolymerisatie.
Unzipping: Pn Pn-1 + M
•CH2 C• + Mw O O O O O O O O O O O O O H N
C• + O O O O 0 100% Formed monomers ─ = unzipping Random chain scission: ─ = random chain scission Pn Pn-x + Px
MeOH MeOH O O MeOH O O O O O O O O O O O O O O n MeOH MeOH MeOH Plastic recycling - Feedstock recycling
Thermal depolymerization
Imitates geological processes of fossil fuel formation.
Longest chains are C18. Currently applied for turkey waste, with energy efficiency of 85% Estimated efficiency for polymers is estimated to be > 95%!!!
260°C, 40 bar
15 min.
Me (85 kg) 19 kg oil, 3.5 kg gas, 3.5 kg minerals, 62 L distilled water Polymer Characterization.
DSC – Tg, Tm, Cp
GPC/SEC – Mn, Mw, Mz
Intrinsic viscosity – Mv
XRD/SAXS/WAXS – crystallinity, unit cell parameters, space group, morphology, ….
NMR – tacticity, end group analysis Differential scanning calorimetry (DSC)
DSC is widely used to measure Cp, Tg, Tm, Tc, crystallinity, purity, etc.
Power Compensation DSC (S=sample, R Heat-flux DSC (disk-type) S=sample, R = reference, = reference, 1 = micro furnace with heater, (1) disk, (2) furnace, (3) lid, (4) temperature sensors, 2 = temperature sensor). (5) controller and programmer. Typical DSC-curve of a polymer. (1, 3, 5: heat capacity dominating part of the curve, 2: glass transition region, 4: interpolated baseline, 6: melting peak).
Effect of heating rate on melting temperature. The effect of sample mass (thickness) on the DSC melting curves of PE. Gel Permeation Chromatography (GPC) – Size Exclusion Chromatigraphy (SEC)
Mn Ditection methods: UV, Light scatering, refractive index, M Nr of v
Chains Mw
Mz
Mw Intrinsic viscosity (IV). Polymer molecules in solution experience friction depending on their form and size.
h ~ M → viscosity measurements gives the molecular weight, Mv.
to = flow time of the solvent ho = viscosity of the solvent t = flow time of the solution h = viscosity of the solution
hrel = h/ho = t/to = relative viscosity
hsp = (h-ho)/h = hrel-1 = specific viscosity
hsp -1 [η] = lim ≡ lim c ·ln ηrel intrinsic viscosity C→0 c C→0
Mark-Houwink relation:
a [η] = K·Mv K and a are characteristic constants for a specific combination of polymer, solvent and temperature. Ubbelohde
plot of hsp/c (•) and ln hrel/c (○) versus concentration. XRD – SAXS – WAXS
Typical polymer and polymer liquid crystal structures and their respective diffraction patterns. (a) non- crystalline, (b) oriented nematic, (c) oriented smectic-A, (d) a type of oriented smectic-C, (e) two- dimensional crystallinity, chains packed on a hexagonal lattice, (f) three-dimensional crystallinity. NMR
Atactic poly(4-methyl-1-pentene)
50 48 46 44 42 40 38 36 34 32 30 28 26 24 22 ppm
Isotactic poly(4-methyl-1-pentene)
50 48 46 44 42 40 38 36 34 32 30 28 26 24 22 ppm -Overview of polymerization catalysis
Different coordination polymerization mechanisms: ROP, ROMP, (meth)acrylate polymerization, olefin polymerization.
Different catalysts: Metal-based catalysts, organic catalysts and enzymes.
56 Ring Opening Polymerization (ROP) Ring opening polymerization is a versatile process to polymerize a wide range of cyclic monomers. For example:
Why would such polyesters be formed?
Enthalpy or entropy driven?
57 Ring Opening Polymerization (ROP) Not only for cyclic esters, also for example for cyclic ethers and the combination of different cyclic molecules can be ring opened. For example:
58 ROP of cyclic esters.
What are the requirements of the catalyst?
- + d d OMe Metal O O
Ancillary ligand n
Robust and tunable ancillary ligand system Electrophilic metal center (can be cationic) Polarized metal-polymer bond Vacant coordination site to bind monomer 59 Catalysts for ROP of cyclic esters.
Examples of catalysts for ring opening polymerization of cyclic esters.
O O Nu Sn N Nu M N O O N N t-Bu N N M O N t-Bu t-Bu H t-Bu i O PrO O O M = Al, Cr, Mn, Co N Al OiPr Zn + - + - i Cocat: [Ph PNPPh ] Cl , NEt Br , PrO O O O 2 2 4 H N
Me Ph O O O Ph THF X t-Bu Ph Ph M M N t-Bu M O N O N i M O Pr O OMe N N t-Bu t-Bu M = Mg, Ca, M = Y, La M = Mg, Zn Zn 60 Ring Opening Polymerization – mechanism ROP of e-caprolactone.
O O Al O O O O n O n
‡
O O O O δ+ O δ+ O δ+ O Al δ+ O Al Al δ− − Al δ − − O O δ δ− δ O δ− O O O O O
− − + δ δ δ O δ+ O O O
61 Ring Opening Polymerization – mechanism ROP of e-caprolactone. ‡
O O O δ− δ− O δ+ δ+ O O δ+ O Al O Al O Al δ− O O O + O δ O δ− − O δ
O O O n O
O
O O xs O O Al Al O O O O O n O O H+ n O O O O O O 62 H O n Polyhydroxybutyrates
Catalyst requirements: Lewis acidic metal. Free coordination site. Sometimes a cocatalyst is required.
63 Ring Opening Polymerization – mechanism
64 Oxirane-based (co-)polymers
65 Oxirane – carbon monoxide copolymers O O R O R O C O
[catalyst] O [catalyst] O O R n R yields an AB-polymer
O O O R O R O [catalyst] + O O R R n O
[catalyst] 2 C O
yields an AABB-polymer O
R Two similar but different synthetic polymers. 66 Step growth versus chain growth
Mw
0 100% monomer consumptio n ─ = step growth polymerization ─ = chain growth polymerization 67 Oxirane – carbon monoxide copolymers Inversion of configuration
68 Oxirane – carbon monoxide copolymers Inversion of configuration
69 Oxirane – anhydride copolymers
70