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APPLICATION OF SEC IN TWO-DIMENSIONAL LIQUID CHROMATOGRAPHY OF POLYOLEFINS

T. Macko, S.S. Bhati, R. Brüll Fraunhofer-Institute for Structural Durability and System Reliability LBF,

Darmstadt, Germany

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Fraunhofer Institute, Darmstadt, Germany, Division Plastics, Group of Material Analytics

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World-wide production of polyolefins

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Challenges in Polyolefin Analysis

Multidimensional techniques are required to analyze the chemical heterogeneity

• Chemical composition distribution (CCD) • Molecular weight distribution (MWD) • Stereochemical distribution • Comonomer sequence length distribution • Long chain branch distribution (LCB)

MWD CCD

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High-temperature chromatograph from PolymerChar

OVEN for columns

Gradient and

isocratic PUMP

IR Detector OVEN for valves

ELS-Detector AUTOSAMPLER

Solvent selector with 8

solvents

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High-temperature chromatographic instrument

Method selector, solvent selector, column selector and pump selector valves enable to realize:

Method selector

Column selector

Solvent selectors

solvent gradient (SGLC), temperature gradient (TGIC), critical (LCCC), size exclusion (SEC), two-dimensional liquid chromatography (2D-LC) measurements

multimethods, multipurpose = universal liquid chromatograph for chromatographic analysis of polyolefins

IR ELSDWasteWaste Waste

Gradient pump

Isocratic pump

Autosampler

Columnselector

SECcolumn for 2D-LC

Solventselector A

Solventselector B

Samplesolventvalve

SECcolumn HPLC

columns

Valve with filter

Injection valve

MethodselectorInjection

valve for 2D-LC

Pump selector

Pump selector

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Separation of EB copolymers and PE (bimodal HDPE )

Bimodal polyethylene

0 2 4 6 8 10 12 140

1

2

3

4

5

6

7

8

EB77

EB65

EB56 EB35

EB19

ELSD

resp

onse

[V]

(Pea

k ar

ea n

orm

aliz

ed)

Elution volume [mL]

G-10 min

b)

EB5 EB11

PE126

0

20

40

60

80

100

Con

tent

of T

CB

[vol

. %]

8 9 10 11 12 13 140123456789

10

ELS

D re

spon

se [V

](P

eak

area

nor

mal

ized

)

Elution volume [mL]

PE2 PE16.5 PE36.5 PE60 PE118 PE181 PE260

a)0

20

40

60

80

TCB

con

tent

[vol

. %]

linear PE standards

Mobile phase: 1-decanolTCB

Column: Hypercarb 100x4.6 mm

Temperature: 160 °C

Detector: ELSD

PE 2 kg/mol

ethylene/butene copolymers

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Comparison of SEC chromatograms from HT 2D-LC

0.000

0.002

0.004

0.006

0.008

0.010

150149148

148 149 150

b)ELSD

resp

onse

[V]

BiHDPE

Number of fractions

a)0.000

0.002

0.004

0.006

0.008

0.010 BiHDPE

IR re

spon

se [V

]IR-detector

ELS-detector

K.N. Prabhu, R. Brüll, T. Macko, K. Remerie, J. Tacx, P. Garg, A. Ginzburg, J. Chromatogr. A, 2015, 1419, 67.

Solvent peak

Polymer peak

Injection signal

Polymer peak

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0.000.010.020.030.040.05

IR re

spon

se [V

]

BiHDPE

Number of fractions

0.0000.0010.0020.0030.0040.005

150149148

150149148a)

b)

BiHDPE

ELSD

resp

onse

[V]

Comparison of SEC chromatograms from HT 2D-LC

IR-detector

ELS-detector

K.N. Prabhu, R. Brüll, T. Macko, K. Remerie, J. Tacx, P. Garg, A. Ginzburg, J. Chromatogr. A, 2015, 1419, 67.

Solvent peak

Polymer peak

Injection signal

Polymer peak

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Experimental parameters used for HT 2D-LC

Experimental parameters

HT 2D-LC method

I II III IV V

Transfer loop volume [μL] 200 100 50 100 100

Flow rate in HPLC column [mL/min] 0.2 0.1 0.05 0.02 0.01

Flow rate in SEC column [mL/min] 2.5 2.5 2.5 1.5 1.5

Length of the SEC column [mm] 150 150 150 300 300

Time between injections into SEC column [min] 1 1 1 5 10

Total number of HPLC fractions [No. of SEC analysis] 100 200 400 200 200

Total volume of the solvent gradient [mL] 10 10 10 10 10

Number of fractions in the gradient 50 100 200 100 100

Time of complete HT 2D-LC analysis [min] 100 200 400 1000 2000

ELS-detector IR-detector

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Contour plots of BiHDPE obtained from HT 2D-LC

IR-detector ELS-detector

Polyethylene pipes

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High Temperature 2D-LC of bimodal HDPE (HPLC SEC): 2D-plot – chemical composition distribution and molar mass distribution visible

Column: Hypercarb. Mobile phase: 1-decanolTCB. Temperature: 160°C. K.N. Prabhu, R. Brüll, T. Macko, K. Remerie, J. Tacx, P. Garg, A. Ginzburg, J. Chromatogr. A, 2015, 1419, 67.

Bimodal polyethylene

HDPE LLDPE

Low molar mass PE (incl. oligomers)

Both axis in the contour plot are calibrated

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Liquid chromatography under critical conditions of iPP

Column: Hypercarb. Critical mobile phases: 2-octanol/TCB, 87/13 vol. Temperature: 160°C.

S.S. Bhati, T. Macko, D. Mekap, R. Brüll, Macromol. Chem. Phys., 2015, 216, 2179.

Critical conditions

1.0 1.5 2.0 2.5 3.0 3.50.000

0.004

0.008

0.012

0.016 iPP1.2

iPP8.6

iPP52.3

iPP136.5

iPP348.3

ELSD

resp

onse

[V]

Elution volume [mL]a) 2.9 3.0 3.1 3.2 3.30.000

0.004

0.008

0.012

0.016 iPP1.2

iPP8.6

iPP52.3

iPP136.5

iPP348.3

b)

ELSD

resp

onse

[V]

Elution volume [mL]2.9 3.0 3.1 3.2 3.3

0.000

0.004

0.008

0.012

0.016 iPP1.2

iPP8.6

iPP52.3

iPP136.5

iPP348.3

c)

ELSD

resp

onse

[V]

Elution volume [mL]

SEC Adsorption LC

Elution volume = constant

Elution volume = increases with MM

Elution volume = decreases with MM

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Separation of high impact PP with high temperature 2D-LC (LCCC of iPP + SEC) with IR-detection

S.S. Bhati, T. Macko, D. Mekap, R. Brüll, Macromol. Chem. Phys., 2015, 216, 2179.

Amorphous ethylene-propylene copolymers

Column packing: Hypercarb. Mobile phase: 2-octanol/ODCB, 83/17 vol. (constant composition) Temperature: 160 °C.

iPP

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Separation of PP-g-MA

Contour plot (HPLC-SEC) obtained with IR-detector. HT SEC calibrated with PS-standards.

Chromatograms of PP-g-MA. Column packing: Silica gel. Mobile phase: Gradient Decalin Cyclohexanone. Temperature: 160 °C.

K.N. Prabhu, T. Macko, R. Brüll, K. Remerie, J. Tacx, P. Garg, A. Ginzburg, J. Chromatogr. A, 2016, 1441, 96.

iPP

PP-g-MA

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Contour plot for EP copolymer

Only the polymer peaks are selected and plotted as a contour plot.

Contour plot for EP copolymer (59.7 wt. % ethylene)

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Calibrations of IR-response (concentration of polymer), SEC (MMD) and HPLC separation (CCD)

CCD

MMD

Concentration of polymer

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Differences in the contour plots = differences in MMD and CCD Matrix approach

The first EP sample The second EP sample

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Contour plot = matrix

One contour plot chosen as reference

Subtraction of matrices

unique segments in samples

Addition and subtraction of matrices

identical segments in samples

Results = MMD and CCD presented in

the contour plots

Matrix approach

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Polymer sample EP59.7 EP39.8

Segments Identical Unique Identical Unique

Mass fraction

[wt. %] 10.5 89.5 10.5 89.5

Average M [kg/mol] Mn Mw Mn Mw Mn Mw Mn Mw

79.6 112.6 107.1 141.7 79.6 112.6 107.6 147.5

Average EC [wt. %] ECn ECw ECn ECw ECn ECw ECn ECw

44.32 44.45 59.6 59.92 44.32 44.45 36.08 36.89

Average MM and CD of unique segments and indentical segments in the compared copolymer samples

S.S. Bhati, T. Macko, R. Brüll, Polyolefins J, 2016, in print.

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Unique segments of two copolymers Both the

copolymers contains 89 wt. % unique segments

S.S. Bhati, T. Macko, R. Brüll, Polyolefins J, 2016, in print.

MMD CCD

MMD CCD

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Identical segments of two copolymers Both the copolymers had

10 wt. % identical segments

CCD

CCD

MMD

MMD

S.S. Bhati, T. Macko, R. Brüll, Polyolefins J, 2016, in print.

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Acknowledgement Prof. R. Alamo (Uni of Florida) Prof. V. Busico (Uni of Naples) Dr. I. Suarez, Dr. B. Coto, (Uni of Madrid) Dr. Ch. Boisson, Dr. O. Boyron, Dr. V. Monteil (Uni of Lyon) Prof. M. Terano, Prof. T. Tanaike (JAIST) Prof. J.B.P. Soares, (Uni of Waterloo) Dr. C. Descours, F. Karbach, Dr. R. Duchateau (Uni of Eindhoven) Dr. T. Poltimäe, Prof. A. Krumme (Uni of Tallinn) Dr. D. Mekap, Dr. R. Cong, Dr. Z. Zhou, Dr. W. deGroot (Dow) Dr. S. Losio (Uni of Milano) Dr. I. Mingozzi, Dr. V. Dolle (LyondellBasell) Prof. W.H. Sun (Chinese Academy of Sciences) Dr. G. van Doremaele, Dr. R. Bernardo (Lanxess) Dr. L. Pereira, Dr. H. Ritchie (Thermo Fisher Scientific) Dr. A. Ginzburg, Dr. J. Tacx, Dr. K. Remerie, Dr. P. Garg (SABIC) Dr. B. Monrabal, J. Sancho-Tello, Dr. A. Ortin, P. de Hierro (PolymerChar) Dr. R. Chitta (DSM Resolve) Dr. S. O‘Donohue, J. Yakhoul, R. Linz (Agilent)

This research forms part of the research programme of the Dutch Polymer Institute (DPI), project #750.

Dr. K.N. Prabhu, Dr. D. Mekap, Dr. J.-H. Arndt, (Fraunhofer Institute LBF)

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Fraunhofer Institute, Division Plastics,

Group of Material Analytics Darmstadt, Germany

High Selective Liquid Chromatography Separations

of Polyolefins

Thank you for your attention!