Einführung in die Technische Chemie · high branching, low density (910 -930 kg/m3) soft melting...

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D. Vogt Einf. In die Techn. Chemie

Dieter Vogt

Prof. Dr. Dieter VogtFakultät Bio- und Chemieingenieurwesen

Lehrstuhl für Technische Chemie

Einführung in die Technische Chemie

Montag, 12-06-2017

Polymerisationen I


Polymers

Definitions:

[Elias 97] Polymers are a group of chemical substances composed of macromolecules, which in turn is a molecule composed of a largenumber of atoms

International union of pure & applied chemistry (IUPAC)polymer molecule = macromolecule

[Frank 96] Plastics are technical materials comprised of macromoleculeswith organic groups which are obtained by chemical conversion. Theirmolecular weight lies between 8 000 and 6 000 000 g/mol

For a nice introduction to polyethylene catalysis:http://www.uyseg.org/catalysis/polyethene/poly1.htm

http://www.fbv.fh-frankfurt.de/mhwww/KKC-Vorlesung/inhalt-KKC.htmSlide collection (in German)

last change: 170531

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Konstitution von Polymeren

Art der Monomeren (Ethen, Propen, Butadien, ...

Sequenz der Monomeren (alternierend, statistisch, ...

Art und Länge der Verzweigungen (lang, kurz, ...

Molmassenverteilung

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Polymere

Macromolekulare Verbindungen mit Molmassen von 104-106

1. Allgemeines zur Klassifizierung1.1 Polymer-Typen (Monomere = Baueinheiten)

Unipolymere

Copolymere

alternierend

statistisch

Blockcopolymere

Pfropfcopolymere

Terpolymere

A A A A A A A

A B A B A B A

A B A A B B A

A A A A A A A B B B B B B

A A A A A A A

B

B

B

B

B B B B

A B C

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Typen von Polymerverzweigungen

Kurzkettenverzweigung

Langkettenverzweigung

Netzwerke (vernetzte Polymere)

ungeordnet

geordnet, z.B. Leiterpolymere

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Branching Forms

Linear chain Cyclic molecule Three-limbed star

Comb molecule Tree-like molecule Dendrimer

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Polymer Architecture

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Configuration of Polymers

Tacticity

isotactic

syndiotactic

atactic

cis- and trans-tacticity

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Conformation of Polymers

RH

HR

RH

RH

HR

Spacial arrangement of the polymer chain

e.g. for isotactic polypropylene

3/1-helix, 3 monomer units in 1 turn

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b

Helical form of stereoregulated polymers(e.g. isotactic PP)

Helix form crystallisation

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Polymer Architecture


Polymerization

Polymers are complex materials:

chemistry (monomer components)

molecular weight distribution

branching, cross-linking, end groups

tacticity, crystallinity, morphology of the crystals

for copolymers: monomer ratio, order of the monomers,

statistics of the inclusion

for heterogeneous polymerisation: particle shape and size

distribution, distribution of polymer phases

additives and impurities

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Types of Polymerisation Reactions

1) radical polymerisation

2) anionic polymerisation

3) cationic polymerisation

4) metal complex catalysed polymerisation

5) group transferring polymerisation

6) (co-polymerisation)

e.g.: - Philips catalyst- Ziegler-(Natta) catalyst - metallocenes

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D. Vogt Einf. In die Techn. Chemielast change: 170611

Polymer Additives

Different classes of polymer additives

Antifogging agentsAntimicrobialsAntioxidantsAntistatic agentsColourantsCoupling agentsFlame retardantsSmoke suppressantsFoaming agentsFragrancesImpact modifiersLubricantsMould release agentsPlasticizersReinforcing agentsUV stabiliyersHeat stabilizersSurface active agents

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D. Vogt Einf. In die Techn. Chemielast change: 170611

Monomer-Verknüpfungen

Polymerisation

Polykondensation

Polyaddition

StyrolPolystyrol

Adipinsäure

DiaminohexanPolyamid (6,6)

Diphenylmethandiisocyanat

+ 1,4-Butandiol

Polyurethan

HOOC (CH2)4 COOH

H2N (CH2)6 NH2

+

n

n - 2 n HOHC (CH2)4

O

C N

O H

(CH2)6 N

H

n

NNCC

OOHO

OH

+

n

nn

C N

O H

OO (CH2)4 CH2 N C

H O

n

n


Wiederholungseinheiten

n O

O OR1

n O

R3 R2 N

H

n O

R5 R4 N

H

O

n

n

Polyurethan

Polyamid

Polybutadien

PolycarbonatPolyethylen

n

Polypropylen n

Polystyrol

O

O

R6

R7

n

Polyester

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PolyacrylatPolyvinylchlorid

n

O R9R8

n

Polyether

Cl n

COOR10

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Wiederholungseinheiten


Polyadditionen

NH

O

Rn

C

O

R NH

COOHO

On

H2N R' NH2 OCN R NCO+H

H

H

H

nN R' N C

O

N R N C

O

HO R' OH NCOROCN+ O R' O C

O

N R N C

O nH

HPolyurethane

Polyharnstoffe

Poly--propionsäure

Ringöffnende Polyadition, z.B. von Lactamen

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+ n H2OHOOC R COOHHO R' OH + O R' O C R

O

C

On

O

+ n HClHO R' OH ClOC R COCl+ O R' O C R

O

Cn

+ n H2OHO R COOHn

O R C

O

+ n H2OH2N R' NH2 HOOC R COOH+H

HN R' N C

O

R C

O

n

+ n CO2OCN R NCO R N C Nn

Polykondensationen

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Types of Polymerization Reactions

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• Growth throughout matrix• Rapid loss of monomer early in

reaction• Similar steps repeated throughout

reaction process• Average molecular weight increases

slowly at low conversion=> high extents of reaction arerequired to obtain high chain length

• Ends remain active (no termination)• No initiator necessary

Step-growth polymerization

• Growth by monomer addition at onechain end only

• Some monomer remains, even after long reaction times

• Different steps operate at different stages of mechanism (i.e. initiation, propagation and termination)

• Molar mass of backbone chainincreases rapidly at early stage andremains approximately the same throughout the polymerization

• Chains not active after termination• Initiator required

Chain-growth polymerization

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Pn

Umsatz 1

Stufenreaktion

‘‘lebende Polymerisation’’

Polymerisation

Polymerisationsgrad

Carothers Gleichung (für Stufenreaktionen)Pn = 1-x1

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Wichtige Polykondensate

Name chemische Struktur

Polyamid 6.6 -[NH-(CH2)6-NH-CO-(CH2)4-CO]n-

Polyamid 6.10 -[NH-(CH2)6-NH-CO-(CH2)8-CO]n-

Polyethylentherephthalat (PET) -[O-(CH2)2-O-CO-pPh-CO]n-

Polycarbonat A -[O-pPh-C(CH3)2-pPh-O-CO]n-

Polyarylate -[O-Ar-O-CO-Ar-CO]n-

Polyphenylensulfid -[S-pPh]n-

Polysulfid -[S-R]n-

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Wichtige anionische Polymerisate

Monomer chemische Struktur Anwendung

Butadien -[CH2-CH=CH-CH2]n- Kautschuk

Isopren -[CH2-C(CH3)=CH-CH2]n- Kautschuk

Methylcyanacrylat -[CH2-C(CN)(COOCH3)]n- Klebstoff

Ethylenoxid -[O-CH2-CH2]n- Verdicker

Formaldehyd -[O-CH2]n- Werkstoff

-Caprolacton -[O-CO-(CH2)5]n- Weichmacher

-Caprolactam -[NH-CO-(CH2)5]n- Werkstoff

Polymers_01/21last change: 170531


Wichtige kationische Polymerisate

Monomer chemische Struktur Anwendung

Isobuten -[CH2-C(CH3)2]n- Kautschuk, Klebstoff

Vinylether -[CH2-CH(OR)]n- Klebstoff, Textilhilfsmittel

Tetrahydrofuran -[O-(CH2)4]n- Weichsegmente in Polyurethanen

Ethylenimin -[NH-(CH2)2]n- Papierhilfsmittel, Flockungsmittel

Trioxan -[C-CH2-O-]n- Werkstoff

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Polymer Production

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Polymer Consumption

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Types of Polyethylene

radical polymerisation at high pressures (150 - 350 MPa)

high branching, low density (910 - 930 kg/m3)

soft

melting point ca. 105 - 115°C

crystallinity 50 - 70%

High Density Polyethylene (HDPE)

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Low Density Polyethylene (LDPE)

catalytic polymerisation at relatively low pressures

low branching, high density (950 - 970 kg/m3)

hard

melting point ca. 125 - 135°C

crystallinity 80 - 90%


Start

Kinetik von Polymerisationsreaktionen

Kettenwachstum

Radikalische Polymerisation via Kettenreaktion

last change: 170611

Mechanismus

I 2 R

R + M RM

RM + M RM(n+1)

Kettenabbruch

Kettenübertragung

RMm + RM

n

RMm + RMn

RM(m+n)R

Disproportionierung

Kombination

RMn + HÜ RMn + Ü

rP = kP f kD[I] / kAb [M]

Bruttoreaktionsgeschwindigkeit rP

kP = Geschwindigkeitskonst. Polymeris.kD = Geschwindigkeitskonst. InitiatorzerfallkAb = Geschwindigkeitskonst. Kettenabbruchf = Kettenwachstumsfaktor des Initiators[I] = Initiatorkonzentration[M] = Monomerkonzentration

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Molecular Mass Distribution

dNN

MMn Mw

Mn = wp/Mp

1

p

Mw = wpMpp

wp = portion with the mass Mp in the polymer

Mp = molecular mass of a molecule with the polymerization degree p

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(a) disproportionation and (b) recombinationas main mechanism of chain termination.

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Mass distribution function wP of the polymerisation degree P of polystyrene

Polymerisation degree P

wP·1

04

a)

0

2

4

6

8

10

0 500 1000 1500 2000 2500 3000

Polymerisation degree P

wP·1

04

b)

0

2

4

6

8

0 500 1000 1500 2000 2500 3000

Kinetik von Polymerisationsreaktionen

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Metal-Complex Catalysed Polymerisation

Catalyst components:

metal compound of IV - VIII sub group

e.g. TiCl4, CoCl2, Cr(C6H6)2

organo-metallic compound of I - IV main group

e.g. AlEt3, Et2AlCl2, MgEt2, n-BuLi

last change: 170611

The metal catalyzed coordination polymerization of alkenes was developed by Ziegler and Natta (Nobel Prize in 1963)

Karl Ziegler1898-1973

MPI Mühlheim

Guilio Natta1903-1979

University of Milan


Alkene Polymerization

TiCl4 + AlEt2Cl TiCl3 * 0.15 AlCl3 * 0.2 AlEtCl2

Early catalysts derived from TiCl4 and an alkylating agent, e.g. AlEt3

brown -TiCl3

Washing, followed by warming converts it to the active polymericpurple -TiCl3

TiCl

ClClTi

Cl

ClTi

Cl AlEt3 Cl

ClTi

Cl

Final activation by alkylation gives the active catalyst

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Cossee - Arlman Mechanism

Cl

ClTi

Cl

[TiCl3]n

AlEt3

Cl

ClTi

Cl

Cl

ClTi

Cl

Cl

ClTi

Cl

polyethylene

Catalysis_27last change: 170531


Ziegler-Natta Catalysis

Isospecific Active Sites

TiCl3 MgCl2/TiCl4/donor

Cl Ti ClCl Ti

Cl*

ClTi

R

Cl

Cl Ti ClCl M

L*

ClM

R

L

L = donor or Cl

Site determines orientation of chain ; monomer minimizes interaction with chain

Stereospecificity by enantiomorphic site control

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7-10 nm

3 nm

Ball milled MgCl2

Structure of the active species in supported catalyst according to Chien.

Cl

Ti

Cl

Cl

Mg

Cl

Cl

Cl

Cl

Cl Mg

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Low Pressure Ethylene Polymerisation

Ethylene Polyethylene

stirred tank

dissolved Ti-compound

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Polymerisation with Metallocenes

Metallocenecatalyst

components:

Walter Kaminsky1941 –

University of Hamburg

last change: 170611

chains, cyclic and cage structures


Single-Site Polymerization Catalyst

(Zirconocene, Sinn, Kaminski; 1978-1980)

cocatalyst: MAO = methylalumoxane = "[(CH3)AlO]n"

MAOMAO

ethene

Zr CH3 ZrCH3

ZrCH3

ZrCH3

ZrCH3

CH3Zr

Cl

Cl- CH3[MAO]

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Selective Polymerization of Propene

W. Kaminsky, M. Arndt in Appl. Homog. Catal. with Organomet. Comp. (Eds.: B. Cornils, W. A. Herrmann) Vol. 1, VCH 1996, pp. 220-236.

C2vTiClCl

atactic

C2ZrCl

Cl

isotactic

CSHfCl

Cl

syndiotactic

last change: 170611

Hans-H. Brintzinger



Fliping Mechanism for Metallocenes

AlO

AlO

AlO

Al+ZrCl

ClZr

CH3MAO

Methylaluminoxane (MAO)

catalyst activation

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Polymerization Catalysts

Late Transition Metals

iPr

iPr

NO

Ar

Ni

PhMeCN

iPr

iPrNN

Pd

Me OEt2

iPr

iPr

iPr

iPr

N

NFe

iPr

iPrN

Cl Cl

/ MAO

Brookhart, Johnson Bennett, Grubbs

Brookhart,Small, BennettGibson

tolerant of functional groups, but slow + poor comonomer incorporation

highly active, but mainlyfor ethene polym./oligom.

last change: 170531


NNNi

Br Br

NNNi

Br Br

NNNi

Br Br

Polyethylene with Designer Catalysts

highly branched polymer=> rubber

polymer with short chain branches=> soft, films

highly linear polymer=> hard, fibers

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Technisch bedeutsame ZN Polymere

Monomers Polymers typical catalysts

Ethylen HDPE TiCl3/AlR3

Propylene isotactic PP TiCl3/R2AlCl

Butylene-1 isotactic poly(1-butylene) TiCl3/Et2AlCl

Butadiene cis-1,4-polybutadiene Co(OOCR)2/R3Al2Cl3

Isoprene cis-1,4-polyisoprene TiCl3/AlR3

Ethylene + propylene + unconjugated diene EPDM polymers VOCl3/R2AlCl

last change: 170531


Chain Termination Reactions in ZN Catalysis

exchange of alkyl groups P

M

Al

Me

P

M

Al

Me

+P

M

Al

Me+

-H elimination

H

M

P

H

M

P

H

M

P

+

-methyl elimination (only propene)

Me

M

P

Me

M

P

Me

M

P

+

last change: 170531

-bond metathesis

+M

H

M

H

+H

M

P P P

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1. Importance of polymerisation

2. Molecular architecture of polymers: – tacticity, branching, MWD, …

Polymerisation I - Zusammenfassung

4. Radical chain polymerisation – initiation, propagation, termination

6. Heterogeneous catalysis: - Phillips catalyst

5. MWD: - Kinetic chain length, Anderson-Schulz-Flory-distribution

3. Polymerisation mechanisms: – chain, living, step,…

7. Coordinative polymerisation: - Ziegler-Natta & Metallocene catalysts

last change: 170531

Einführung in die Technische Chemie · high branching, low density (910 -930 kg/m3) soft melting...

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