Polymerisation Processes Polymerisation Processes Polyethylene ...

Polymerisation Processes 

Polymer Processes 

Dr. Klaus-Dieter Hungenberg, BASF AG Ludwigshafen Vorlesung Polymerisationstechnik, Universität Paderborn, WS 07/08 Polymer processes 

Polyethylene 

Homo- und Copolymers of ethylene: 

n 

• PE is industrially produced bay radical- and coordinative polymerization 

• Polyethylene (PE) is semi-crystalline, non-polar thermoplastic material 

• Most important standard plastics with highest production volume 


1 

3 

Polymerisation Processes 

Why look processes like as they do? 


Polyethylene 

structure 

crystallinity [%] 

Melting point [°C] 

density [g/cm 3 ] 

LDPE LLDPE HDPE PP 

Long- and 

Short chainbranching 

50 - 55 

106 - 120 

0,91 - 0,93 

Linear with 

short chainbranches 

55 - 60 

125 - 130 

0,91 - 0,93 

Linear with few 

short chainbranches 

70 - 80 

128 - 136 

0,93 - 0,96 

Linear 


~ 70 

164 - 166 

0,91 

2 

4

Polyethylene applications 

• Films 

• packaging material 

• injection molding 

• pipes 

• electrical insulation material 


Polyethylene melt flow index 

Melt Flow Rate / Melt Flow Index 

= a measure for chain length / molecular weight 

Amount of molten polymer [dg/min], that flows at defined conditions (pressure 

and temperature) through a defined capillary. 

Standards: ASTM 1238 / ISO R1133 

weight 2,16 kg / 21,6 kg 

temperature 190 °C 

geometry capillary: 

D=2,095 mm 

L=8 mm 

High MFR = low molecular weight 

Low MFR = high molecular weight 


5 

7 

Polyethylene density 

Density correlates with crystallinity and structure of PE: 

amorphous PE: ρ = 860 kg/m³ 

crystalline PE: ρ = 1000 kg/m³ 


Polyethylen Processes 

PE 

radical coordinative 

homogen homogenous 

• bulk 

(LDPE high 

pressure process) 

homogenous heterogenous 

• solution • Suspension 

(3 Phase „Slurry“ 

polymerization) 

• Gas phase 

• bimodal: 

slurry-slurry 

slurry-GP 

GP-GP 

Reactions - 

mechanism 

phases 

processes 


6 

8

High Pressure Polyethylene Processes 

High pressure process 

in one phase region 

low pressure process in 

two phase region 


R2 

Side Reactions inHigh Pressure Polyethylene 

R1 

Chain scission – unsaturated chains 

R1 CH 2 CH CH 2 R2 

Intermolecular transfer to polymer – long chain branching 

CH CH 2 

2 

CH C 

2 

H2 + 

CH CH CH CH 2 

2 

2 

2 

CH CH CH R3 

2 

2 

2 

R2 

R1 

CH CH 2 

2 

CH CH 2 

3 


+ 

CH CH C 

2 

2 

CH CH H 

2 

2 

CH 2 

n 

CH 2 

R3 

C 

H 2 

CH 2 

R2 

H2 C 

+ 

+ 

R1 CH CH2 R2 H2C 

H C CH R2 2 R1 C 

C 

H 2 

H2 C 

C 

H 2 

C 

H 2 

C 

H 2 

HC 

CH 2 

CH 2 

C 

H 2 

H 2 

H2 C 

R3 

9 

11 

High Pressure Polyethylene Processes 

Primary 

compressor 

Granules 

Hyper Compr. 

Autoclave 

High pressure cycle 

150-300 bar 

Low pressure 

cycle 

Extruder 

M 

alternative 

High pressure 

separator 

Low pressure 

separator 

T = 200 - 300°C 

P = 2000 - 3000 bar 

Tubular reactor 


Side Reactions inHigh Pressure Polyethylene 

Intramolecular transfer to polymer – short chain branching 

R1 CH 2 CH 2 CH 

H 

CH 2 

C 

H 2 



CH 2 

CH 2 

CH 2 

CH H 2 

C 

H2 CH 2 

CH 2 

CH 3 

C 

H 2 

CH CH 2 CH 3 

CH CH 2 CH 3 

R1 CH 2 CH 2 C H 

CH 2 

n 

C 

H 2 

n 

C 

H 2 

CH 2 


CH 2 

C 

H 3 

CH 2 

CH 2 

CH 2 

n 

M 

C 

H 2 

CH 2 


CH 2 

CH 2 

CH 2 

CH 3 

CH 2 CH 2 CH 2 CH 2 CH 2 

R1 CH CH CH CH CH CH CH CH 2 2 2 

2 2 2 

CH 2 

CH 3 

CH 2 

CH 3 

Butyl side groups 

Ethyl side groups 

10 

12


I, M 

300 

200 

100 

Activation energy and volumes in LDPE 

Different operation modes in LDPE reactors 

Single monomer feed of monomer 

Multiple initiator possible 

Single initiator feed 

I 

double initiator feed 

300 


200 

100 

I, M 

Multiple feed of monomer and initiator 

I, M 

I, M 

13 

15 

Process parameters and properties - Trends 


Coordinative Polyethylene Processes 


14 

16

Solution Coordinative Polyethylene Processes 

Solution process: 

• broad range of comonomer types and densities possible 

• pure products 

• limitation: high molecular weight (high temperature, transfer to solvent) 

• temperature well above melting point of PE 

• commercial processes: 

• processes with very short residence time, e.g. 2 min: 

• Nova Sclairtech / Advanced Sclairtech 

• Sabic / Stamicarbon Compact solution process 

• processes with longer residence time e.g. 30 min: 

• Dowlex 

• Mitsui 



Sclairtech Dowlex 

temperature 200 - 300 °C 160 °C 

pressure bis zu 100 bar 27 bar 

solvent cyclohexane C8 / C9 paraffines 

Residence time approx. 2 min approx. 30 min 

heat removal: convective convective and conductive 


17 

19 


Flowsheet for solution polymerization (DSM) 

Ethylen 

Comonomer 

solvent 

Solvent recycle 

venting 

Additives 

Absorber Reactor Flash-Tank 

Mixer 

Extruder 

Additive 

solvent Hexane 

Temperature 130°C 

Residence time ~ 10 min 

Solid content < 10 % 

adiabatic 

High space time yield 

Reactor volume 5 m 3 for 5 t HDPE/h 

Solvent purification 

Flash 

-Tank 

HDPE-Granules 


Slurry Coordinative Polyethylene Processes 

Slurry process: 

• developed for HDPE 

• Limitation: low density, low molecular weight: partial solubility of the polymer 

in the suspension media, fouling 

• suitable for densities above 930 kg/m³ resp. 920 kg/m³ (with SSC) 

• CSTR‘s or slurry-loop reactors used 

• suspension media: paraffines, e.g. hexane, isobutane 

• many commercial processes: 

• processes with loop reactor 

• Phillips Loop 

• Solvay 

• processes with stirred tank reactors 

• Hostalen 

• Mitsui CX 


18 

20

Slurry Coordinative– Phillips Loop 

Flowsheet of the Phillips Loop process 

a) Catalyst hopper and feed valve; b) Double loop reactor; c) Flash tank; d) Purge 

drier; e) Powder-fed extruder; f) Impeller; g) Sedimentation leg 

Suspension media: 

isobutane 

T = 85 – 100 C 

p = 37 bar 

residence time 30 – 60 min 

solid content: up to 50 % 

high specific surface 

reactor completely filled 


Polypropylene applications 

PP is versatile in application: 

• packaging material (flexible films and rigid packings) 

• fibers 

• injection molding parts for automotive, electrical applications, consumer 

electronics 

• Chemical equipment, piping 

High growth rates for PP 


21 

23 

Fluidized Bed Polyethylene Processes 

Fluidized-bed process 

a) Catalyst hopper and feed valve; b) Fluidized-bed reactor; c) Cyclone; d) Filter; 

e) Polymer take-off system; f) Product recovery cyclone; g) Monomer recovery 

compressor; h) Purge hopper; i) Recycle compressor; j) Recycle gas cooler 

T=80 – 100° C 

P = 7 – 20 bars 

RTD comparable to CSTR 

Body widening in upper 

part of the reactor in order 

to reduce gas velocity 

Partly condensation 

cooling („condensed mode“ 


Polypropylene structure 

Crystallinity correlates with stereo selectivity and melting point 

Isotactic = crystalline 

Atactic = amorphous 

Isotactic PP 

misinsertion 

syndiotactic PP 

atactic PP 


22 

24

Types of Polypropylene 

• homopolymers 

• random-copolymers 

with ethylene (1-8 wt.-%) 

mit 1-butene 

terpolymers 

• heterophasic copolymers 

at least two-stage processes, 

in which a second, 

elastomeric phase is generated 


Spheripol Process 

Spheripol process 

a) Loop reactors; b) Primary cyclone; c) Copolymer fluidized bed; d) Secondary and copolymer cyclone; 

e) Deactivation; f) Purging 

1. Stage: 

Matrix homopolymer in bulk 

in loop-reactors 

2. stage: 

Impact-Copolymers in gas 

phas polymerization 


25 

27 

Polypropylene Processes – a variety 

Slurry process in hydrocarbon slurry, tank or loop reactors 

Novolen gas phase, vertical stirred powder bed 

Innovene gas phase, horizontal stirred powder bed 

Unipol fluidized bed 

Spheripol slurry loop reactors ( + gas phase copolymer) 

Mitsui slurry bulk + gas phase 

Borstar liquid / scf proyplen (+gas phase copolymer) 

MZCR gas phasem, multi zone circulating reactor 

Cat, cocat. 

C 3 , H 2 , 

1.Reactor 

PP homopolymer 

slurry 

gas 

Active 

powder 

C 3 , C 2 , 

2. Reactor 

PP copolymer 

gas 

Extrusion 


BASF/ Novolen Gas Phase Process 

BASF gas-phase Novolen process 

a) Primary reactor; b) Copolymerizer; c) Compressors; d) Condensers; e) Liquid pump; f) 

Filters; g) Primary cyclone; h) Deactivation/purge 


26 

28

Amoco Gas Phase Process 

Amoco – Chisso gas-phase process 

a) Horizontal reactor; b) Fluidized-bed deactivation; c) Compressor; d) Condenser; 

e) Hold/separator tank 


Borstar Process 


29 

31 

Unipol Fludized Bed Gas Phase Process 

UCC/Shell – Unipol fluidized-bed process 

a) Primary fluidized bed; b) Copolymer fluidized bed; c) Compressors; d) Coolers; e), 

f) Discharge cyclones; g) Purge 


processes with different reaction zones in one reactor: 

M Z C R 

RISER 

fa st 

fluidization 

(upw ard 

tra n s p o rt) 

Catalyst 

in le t 

Propylene 

barrier 

stream 

DOWNER 

packed 

bed 

(m oving 

downward) 

Product 

discharge 

Gas 

circulating 

com pressor 

B A R R IE R S E C TIO N 

Condenser 

Ethylene 

stripping 

colum n 

Propylene 

fe e d 

Heat 

exchanger 

Basell‘s spherizone® Draught tube reactor proposed by 

Weickert 


30 

32

Tailoring of mwd and comonomer distribution 

: 

• new property combinations 

different approaches possible: 

• multistage process 

• reactors with different reaction zones 

• multisite - catalysts 

% 

Reduced 

impact 

strength. 

Migration, 

taste. 

Smoke 

and odour 

during 

extrusion 

Processability, 

stiffness 

Matrix 

Mechanical 

strength 

Conventional 

ESCR and creep resistance 

Melt 

strength 

during 

extrusion 

Molecular weight (= polymer chain length) 


Bimodal 

Controlling mmd by different methods 

Aternative processes for 

bimodal PP 


M 

H 2 

H 2 

t 

33 

35 

Melt flow dependent in mwd 

normierte Viskosität η/η o 

10 0 

-1 

10 

-2 

10 

-3 

10 

melt flow behaviour of different HDPE at 190°C 

rel. Häufigkeit 

HDPE 3 

HDPE 2 

HDPE 1 

Molmasse 

-4 

10 

-5 

10 

-3 

10 

-1 

10 

Scherrate γ / s 

1 

10 

3 

10 

-1 


Weight % 

Controlling mmd by different methods 

V 

M i 

Ti 


V 

V 

V 

Ti 

Ti 

Ti 

34 

36

Bimodal properties by multi-site catalyst 

unimodal process with multi-site catalysts: 

• bimodal polymers can be produced with multi-site catalysts in 

single stage processes: 

Kim, J. D., Soares, J. B. P., Journal of Polymer Science: Part A: 

Polymer Chemistry, 38, 1427-1432, (2000) 

• lower investment costs compared to multireactor processes / 

processes with multizone reactors 

• control of polymer structure more difficult / less flexible 

• narrower product window compared to multistage processes 


Bimodal properties in a reactor cascade 

catalyst Cocatalyst 

M Propylene 

hydrogen 

1. Reactor 2. Reactor 

M 

Silo 

Catalyst poison 

Propylene 

hydrogen 

Temperatur[°C] 

H 2 -concentration 


M w 

Catalyst poison 

controls fraction in 2. 

reactor 

37 

1. Reactor 2. Reactor 

low high 

low high 

800.000- 

1,5 Mio 

50.000- 

200.000 

39 

hydrogen response for Ziegler catalysts 


Bimodal properties in an oscillating reactor 

M 

1. Reaktor 

Katalysator Cokatalysator 

Propylen 

Wasserstoff 


38 

40

Styrenic Polymers 

α-MeS 

P[S/a-MS] 

P[a-MS/AN] 

-heat resistant 

S/Bu (block-) 

copolymers 

- tough 

- translucent 

- low weather 

resistance 

Bu 

PS 

- transparent 

-stiff 

-brittle 

MMA 

Polybutadienerubber 

HIPS 

- tough 

- opaque 

- low weather 

resistance 

MBS, MABS 

- tough 

- transparent 

Acrylnitril 

Polybutadienrubber 

ABS 

- tough 

- opaque 

- low weather 

resistance 

MMA 

PSAN 

-environmental 

stress resistant 

Polyacrylaterubber 

ASA 

- tough 

- opaque 

- weather 

resistance 


Styrenic Polymers – processes over the years 

IG Farben, 1936 Union Carbide, 1943 Dow, 1952 BASF 1965 


41 

43 

Styrenic Polymers – thermal initiation 

* 

. 

* 

+ 

* 

* 

* * 

H 

+ 

H 

* 

CH3 * CH 

Pn* 


Styrenic Polymers –process and mwd 

* * 

dm 

10 

dP 

-2 


+ Pn 

Styrene / EB 

50-80% conv. 

130-170°C 

2000 4000 6000 8000 

42 

44

Degassing polymer solutions / melts 

Heat 

exchanger 

Vacuum 

Falling strand devolatiizer 

Vacuum 

Extruder 

Falling strangs 

Long diffusion 

Adiabatic flash 

Renewal of melt surface 

Short diffusion paths 

Nearly isothermal flash 

Vacuum 

Vacuum 

´tubular / pipe degassing 

Separation melt/gas 

in tubes 

Heating during evaporation 

Non-isothermal flash 

Thin film evaporator 

Extremely thin films 

Short diffusion ways 

Heating during evaporation 

Nearly isothermal flash 


Brittle and tough materials 

Pure thermoplastic polymer, T g >T use 

brittle, hard tough, hard 

stress, strain, σ 

Area= energy 

elongation, ε 

Thermoplastic polymer + rubber, T g

HIPS, solution/mass ABS - principles 

Rubber ( PBu) dissolved in Styrene 

(/ Ethyl benzene) 

Polymerization of styrene, homo-PS 

and grafted PBu 

Phase separation ( PBu/S and PS/S) 

Phase inversion 

Particle formation 

End of reaction 

A 

B 

D 

C 

Course of reaction 


HIPS – phase inversion in first 2 reactors 

Viscosity 

Reactor 1 Reactor 2 

in out in out 

Homogene 

Lösung 

Polybutadiene in styrene 

Polystyrene in styrene 

conversion 

Phase inversion when 

volume ratio = 1:1 of 

disperse : continuous phase 

Stabilization of particles by 

graft polymers formed in 1. reactor 


49 

51 

HIPS grafting and phase inversion 

PBu in S PS in S 

S S 

Phase separation Phase inversion 

S 

B 

B 

B 

B 

S S 

S S 

B 

B 

B 

S B B 

S 

S 

Graft copolymers needed for 

stabilization of morphology 

S 

B 

B 

B 

B 

B 

S 

S 

S 

S 

B 

BS 

B 

B B 

S 

S 

S 


HIPS – phase inversion in first 2 reactors 

Viscosity 

Conversion 


S 

50 

52

HIPS – various continuous processes 


Specific heat removal capacity for different reactors 

1 – SMR, 2- static mixers, 3- empty tube, 4 – stirred tank, 5 extruder 


53 

55 

HIPS – process with static mixers 

solvent 

monomer 

comonomer 

additives 

Recycle solvent 

water 

additives 

water 


SAN copolymers 


54 

56

SAN copolymerization behaviour 

X_Styrol 

1.0 

0.8 

0.6 

0.4 

0.2 

0.0 

Copolymerisationsdiagramm für 

Styrol / Acrylnitril 

0 0.2 0.4 0.6 0.8 1 

x_Styrol 

r S=0.34 

r AN=0.05 


SAN copolymers in CSTR 

To flare 

SAN, 

EB 

Multiple degassing unit: 

toxic AN 

high temperatures give 

yellow polymer 

W-% AN in polymer 

SAN-melt 

To Extruder 

65% AN 

30% AN 

24% AN 

conversion 

10% AN 


M 

PRC 

continous 

SAN-Polymerisation 

degassing 

SAN-Granulat 

57 

59 

SAN copolymers by…. 

Suspension polymerization 

only azeotropic composition 

water- solubility of AN 

Emulsion polymerzation 

semi- batch, starved feed 

shows some haze 

Continuous solution polymerization in CSTR 

all compositions available 


Rubber modification of SAN –> ABS 

rubber from emulsion or solution process 

Emulsion polymerization 

•High glance of surface 

•Yellowish colour 

•waste water 

•Separate polymerization of SAN 

(solution polymerization) and rubber 

(in emulsion) 

1µm 

Solution polymerisation 

Mat surface 

White 

No waste water 

Solution polymerization of SAN in the 

presence of rubber as for HIPS 


1µm 

58 

60

Emulsion Rubbers for impact modification of SAN 

100-250nm 

Product 

Rubber type 

Double bonds 

T g 

Weather resistance 

Low temperature impact resistance 

SAN matrix 

Crosslinked 

rubber 

SAN graft 

ABS 

Polybutadiene 

Many 

-80°C 

- 

high 

ASA 

Acrylic ester+ bifunctional 

monomer 

- 

-40°C 

High 

low 


PMMA – Polymethyl methacrylate 

Some special features 

Strong gel effect 

Low ceiling temperature 

Tendency to depolymerization 

High shrinkage 

Termination by combination and disproportionation 


61 

63 

ABS, ASA via emulsion rubber and solution SAN 

SAN-melt 


PRCS 

M 

vapor 

PMMA – gel an glass effect effect 

M 

PRC 

conversion 

M 

M 

M 

M M M M 

Due to 

glass effect 

M 

Vacuum 

Base rubber 

SAN grafting 

Storage tank 

precipitation 

De-watering 

extruder 


ABS 

Due to 

Ceiling temperature 

50 100 150 200 

100% 

T/°C 

62 

64

PMMA – weak links 

From combination 

O 

O O 

O 

O 

O 

From disproportionation 

Comonomers stop unzipping 

O 

O 


2 

C* 

O 

CH 3 

O 

+ CH2 * 

C* 

O 

CH 3 

O 

O 

Starting point for depolymerization 

MMMMMMMMMMMMMMMMMXMMMMMM* MMMMMMMMMMMMMMMMMX* + M 

PMMA – process for plates and sheets 


O 

65 

67 

PMMA – continuous bulk process 


PVC – suspension process 

⎛ ⎞ 

1 ln⎜ p 

⎟ = ln( 1− 

Φ 

0 

2) 

+ Φ2 

+ χΦ 

⎜ ⎟ 

⎝ p1 

⎠ 

χ=0.98 

s = kH 

2 

2 

p 

0 

p 

p=const- = 

separate monomer phase 


66 

68

PVC – suspension process 


PVC – bulk process, post reactors 

High solid 

Particle size 0.08-0.2 mm 


69 

71 

PVC – bulk process 

Prepolymerization up to 10% 

Post polymerization up to 85-90% 


PVC – bulk process, particle size and stirring 


70 

72

The Nylon revolution 1945 

O O 

N (CH2 ) N 6 C (CH2 ) C 6 n 

H H 


Polyamides – base materials 

ε-Caprolactam: OH 

+6H 

(Ni) 

OH 

H 

-2H 

O 

+H2NOH -H2O N H 

Phenol Cyclohexanol Cyclohexanon Cyclohexanon-oxim 

Hexamethylene diamine: 

Adipic acid: 

+6H 

(Ni) 

Benzene Cyclohexan 

H 2C = CH – CH = CH 2 

H2C – CH = CH – CH2 CN CN 

+CINO 

- HCI 

(H 2 SO 4 ) 

H2 C 

H2C CO 

H2C NH 

H2C CH2 ε-Caprolactam: 


+Cl 2 

+2H 

(Ni) 

+2NaCN 

H2C = CH – CH = CH2 -2NaCl 

Cl Cl 

NC – (CH2) 4 –CN 

+8H 

(Ni, NH3 ) 

H2N – (CH2) 6 –NH2 Adiponitrile Hexamethylendiamin 

H2C H2C CH2 C 

H2C CH2 H 

OH 

H2C H2C CH2 C = O 

COOH 

(CH2 ) 4 

H2C CH2 COOH 

Cyclohexanol Cyclohexanone Adipic acid 

73 

75 

Polyamides – basic structures 

PA 6: Perlon PA6.6: Nylon 

O 

NH ( CH ) 2 C 

NH ( NH 

5 

CH ) 2 C ( 

6 CH ) 2 C 

4 

n 

n 

PA 6: Caprolactam 

PA 11: Undecanlactam 

PA 12: Laurinlactam 

PA 6.6: Hexamethylendiamine 

+ Adipic acid 

PA 6.10: Hexamethylendiamien 

+ Sebacic acid 

PA 4.6: Butandiamine 

+ Adipic acid 


PA6 – basic reactions 

1. Ring opening 

NH (CH2 ) CO + H 5 2O H NH (CH2 ) COOH 

5 

2. Polyaddition 

NH (CH2 ) CO + H NH (CH CO OH 

5 

2 ) 5 

3. Polycondensation 

n 


O 

H NH (CH2 ) CO OH 

5 

H NH (CH2 ) CO OH + H NH (CH CO OH H NH CO OH + H2O 5 2 ) (CH 5 2 ) 5 

n 

m 

n+1 

n+m 

O 

74 

76

Polyamide 6 - VK column 

water 

ε-Caprolactame 

melting 

80°C 

preparation 

Melt filter 

Pre condensation 

250°C, 40 bar 

Mean residence time VK column ≈ 15 - 30 h 

throughput: 

≈ 2000 moto 


M 

VK-column 

270°C 

280°C 

Water 

granulation 

Extractor 

95°C 

silo 

dryer 80°C 

PA6-process – modelling of melt process 

Model input: 

Kinetic scheme and 

parameters 

Non-ideal phase behavior 

using NRTL model 

Model output: 

Molecular weight 

end groups 

Residual monomer 

Oligomer concentration 

Granules 

Vacuum 

(1 mbar) 


180 

160 

140 

120 

100 

80 

60 

40 

20 

simulation results taking into account exp. binary VLE date 

Extract, %, CL, H2O, Oligomers 

NH2-end groups 

degree of polymerization 

dimer, % 

0 

0 

235 240 245 250 255 260 265 270 275 280 

temperature in top of VK-Rohr 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

77 

79 

PA6-process – modelling of each process unit 

Melt polymerization 

Schmelzepolymerisation im VK - Rohr Extraction Extraktion of oligomers Trocknung/Temperung 

Drying, 

N 2 

Caprolactam 

(+Kettenregler) (+chain regulator + 0,5% + H2O) H 2O Bedingungen: 

τ : 9 - 17 h 

T : 250 - 280 °C 

p : 0 - 0,3 bar 

PA 6 - Granules 

Extracttwater 

Bedingungen: 

τ : 17 - 30 h 

T : 95 - 120 °C 

Water 

solid state polymerization 

N2 -O2 Granulation 

air 

Polyamide 6 


PA6-process – modelling of extraction 

Model assumptions: 

Nernst law at phase 

boundaries 

Nernst coefficient dependent 

on monomer concentration 

Fick diffusion in polymer 

phase and liquid boundary 

layer 

Model output: 

Concentration profile of 

residual monomer and 

oligomer in polymer and 

liquid phase 

-H 2 O 

Bedingungen: 

τ : 20 - 40 h 

T : 135 - 180 °C 

nitorgen 

Top2 4 6 8 10 bottom 12 


10 

8 

6 

4 

2 

1 

0.8 

0.6 

0.4 

0.2 

% extractable 

% dimer in granules 

Top 2 4 6 8 10 12 bottom 

78 

80

PA6-process – modelling of solid state condensation 

Model assumptions: 

Polymer end groups, water, 

monomer und oligomere only in 

amorphous phase 

reaction kinetics as in melt 

diffusion coefficients dependent on 

degree of crystallinity 

surface is free of water 

Isothermal spherical particle 

Model output 

Pn, monomer and oligomer 

concentration 

0 10 20 30 40 50 

reaction tim e [h] 


Polyamide 66 - tank process 

mass fraction of caprolactam [%] 

number-average chain length 

0.20 

0.18 

0.16 

0.14 

0.12 

0.10 

0.08 

0.06 

0.04 

0.02 

0.00 

450 

400 

350 

300 

250 

200 

150 

100 

0 10 20 30 40 50 

T = 125°C 

T = 145°C 

T = 165°C 

T = 180°C 

T = 190°C 

model 

reaction tim e [h] 

T = 145°C 

T = 165°C 

T = 190°C 

model 


81 

83 

PA66- basic reactions 

O O 

HO C (CH2 ) C 

4 

OH 

Adipic acid Hexamethylene diamine 

–H 2 O 


+ 

+ H 2 O 

AH-salt solution 

Polycondensation 

O O 

HO C (CH2 ) C 

4 

NH 

NH 

(CH 2 ) 6 

H2N (CH CH2 

) NH 

6 2 

Polyamide 66 – continous tubular process 

H 2 O-Steam 

tube reactor 

Pump 

Separator 

40-60% 

AH-Salt Solution 

Devolatilisation 

e.g. Extruder 


H 

Pump 

Polymer 

Melt 

Postcondensation 

82 

High energy consumption 

Evt. loss of volatiles in 

vapor 

84

Polyamide 66 – countercurrent process – reactive 

distillation 

Reactive 

distillation 

Temperature 

conventional 

Molten diacid 

feed (bb) 

Steam 

Pressure 

atmospheric 

typically 

Gaseous diamine 

feed (aa) 

Polymer 

(aabb) 

Product Mn 

9000 

typically 


Some processes – PET, PBT from DMT 

O O 

CH3 O C C O CH3 Dr. Klaus-Dieter Hungenberg, BASF AG Ludwigshafen Vorlesung Polymerisationstechnik, Universität Paderborn, WS 07/08 Polymer processes 

85 

87 

Polyethylen(butylen)terephtalat, PET, PBT 

O O 

O O 

CH3 O C C O CH3HO (CH2 ) OH 

x 

HO C C OH 

Terephtalic acid ester Diol Terephtalic acid 

transesterification esterfication 

O O 

HO (CH2 ) O 

x 

C C O (CH2 ) OH 

x 

Pre-condensation 

Post-condensation 

O O 

HO C C O (CH2 ) O H 

x 

x=2: PET 

x=4: PBT 

Side reactions: acetaldehyde, THF from butane diol (PBT) 


Rotating disc reactor for PET, PBT 

n 

To force conversion from 0.95 to 0.99 – 

0.995 ( or P n >100), water removal more 

important than for polyamides, because 

of low equilibrium constants 


86 

88

Polyoxymethylene – anionic polymerization of CH 2 O 

CH 2 O 

Purification, drying 

CH 2 O 

R Hexane 

Suspensions polymerization 

Formaldehyde 

(water solution.) 

Formaldehyde 

(Gas) 

R O CH2 O CH2O n 

Acetic anhydride 

End group stabilization by chemical modification 

R O CH2 O CH2O O CH 

n 

3 


Polyoxymethylene – end group stabilization 


O 

89 

91 

Polyoxymethylene – anionic polymerization of CH 2 O 


Polyoxymethylene – cationic bulk process – 

‘Schalenkreis’ 

Milling 

Vacuum 

Heat Stabilizier 

Antioxidant 

Polymerized 

Material 

Additives 


90 

92

Polyoxymethylene – cationic kneader process 


93

Polymerisation Processes Polymerisation Processes Polyethylene ...

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