® ® Trademark of the Dow Chemical Company THERMAL GRADIENT INTERACTION CHROMATOGRAPHY (TGIC) FOR MICROSTRUCTURE ANALYSIS OF POLYOLEFINS Rongjuan Cong 1,

®

® Trademark of the Dow Chemical Company

THERMAL GRADIENT INTERACTION CHROMATOGRAPHY (TGIC) FOR

MICROSTRUCTURE ANALYSIS OF POLYOLEFINS

Rongjuan Cong1, Willem deGroot1, Wallace Yau1 Lonnie Hazlitt1, Al Parrott1, Ray Brown1

Michael Cheatham1, Matt Miller2, Zhe Zhou2

1Basic Plastics Characterization

2Analytical Sciences

The Dow Chemical Company

©2010 The Dow Chemical Company. All Rights Are Reserved. To the extent the user is entitled to disclose and distribute this document, the user may forward, distribute, and/or photocopy this copyrighted document only if unaltered and complete, including all of headers, footers, disclaimers, and other information. User is not authorized to copy this document into a server and/or website and/or any other electronic media.

®


Outline

Overview of SCB Analytical Tool Box What is TGIC?

― Triple Detector TGIC Capability Examples Experimental Set up Conclusions

®


Tool Box of SCB Distribution Analysis

CategoryCategory Separation mechanism CharacteristicsCharacteristics

TREF

CRYSTAF

CEF

Ability of polyolefin chains to crystallize from a dilute solution upon temp changes in a single solvent

Commercially available detectors (Light scattering, viscometer and IR)SCB up to 9 mol%*Cocrystallization

High-temp LC

(Solvent/non solvent)

Solubility and adsorption of polyolefin chains with stationary phase upon solvent composition change

SCB range 0 to 100 mol% comonomerFast for 1D HT-LCLack of satisfactory detector for Mw, IV and composition

*Commonly used conditions

®


Proposed separation mechanismProposed separation mechanismInteraction and desorption of polyolefin chains from stationary phase upon

temperature change in an isocratic solvent

AdvantagesAdvantagesChoice of commercial detectors—For example, IR-4, IR-5, LS and various

viscometersReducing the cocrystallization commonly observed in CEF/CRYSTAF/TREF

Stationary PhaseStationary Phase―HYPERCARB column and various other columns

Mobile PhaseMobile Phase―Choice of isocratic solvents. Pure o-dichlorobenzene

TGIC for Polyolefins

solutionin versussubstrateon polymer ofamount

)(ln

pK

R

S

RT

HpK

+

®


TGIC for wide range of comonomer content

-0.08

0.02

0.12

0.22

0.32

-5 15 35 55 75 95 115 135 155

Oven/Column Temp (C)

IR-4

Raw

Sig

nal 50mol% octene

32mol% octene

0mol% octeneFor HDPE:Crystallization temp by CRYSTAF: ~85oC

Melting temp by CEF/ATREF: 102oC

Melting temp by DSC 135oC

®


0

20

40

60

80

100

120

140

160

0 10 20 30 40 50

Octene mole%

Peak

Tem

p (C

)

TGIC for wide range of comonomer content

•Down to 30° C, TGIC may determine octene content for LLDPE's 38mol% octene.

•Covering all the practical product applications.

®


DSC for wide range of comonomer content

0.0

1.0

2.0

3.0

4.0

5.0

-40 10 60 110

Temp (oC)

He

at

Flo

w (

W/g

)

15mol% octene

HDPE with 0 mol% comonomer

8.5 mol% octene

DSC

®


TGIC CEF

-0.02

0.03

0.08

0.13

0.18

0.23

40 60 80 100 120 140 160 180

Oven/Column temp (oC)

IR-4

Mea

suri

ng s

enso

r

Down to 40oC

13.8mol% octene

-2

8

18

28

38

22 42 62 82 102

CEF Elution Temp (C)IR

-4 R

aw S

igna

l

Down to 30oC

8.5mol% octene

TGIC run times are competitive with CEF runs.

Insensitive to Mw for HDPE from Mw ≥~30,000

®


Triple detector TGICIR-4 detector

• (Methyl and Methylene channels) CCD and CH3/1000C

Two angle LS detector• Mw and Rg if interested• Mw versus comonomer distribution

Differential viscometer • IV and possible LCB information• IV versus comonomer distribution

Example: solution blend of a-PP (Mw20,000)/i-PP (Mw 265,000)/HDPE (115,000) 33.3/33.3/33.3 (wt/wt/wt)

®


-0.01

0.01

0.03

0.05

0.07

0.09

35 55 75 95 115 135 155 175


IR-4

Raw

Sig

nal

Blend of a-PP/i-PP/HDPE—IR4 Detector

a-PP

i-PP

HDPE Baseline resolved

Precise quantification of each component

®


Blend of a-PP/i-PP/HDPE

• Mw info

• Detailed microstructure

Mw LS/IR-4

-0.01

0.01

0.03

0.05

0.07

0.09

35 55 75 95 115 135 155 175


IR-4

Raw

Sig

nal

0.57

0.62

0.67

0.72

0.77

LS 9

0 R

aw S

igna

l

a-PP (20,000)

i-PP (Mw 265,000)

HDPE (115,000)

-0.01

0.01

0.03

0.05

0.07

0.09

35 55 75 95 115 135 155 175


IR-4

Raw

Sig

nal

0.57

0.62

0.67

0.72

0.77

LS 9

0 R

aw S

igna

l

-0.01

0.01

0.03

0.05

0.07

0.09

35 55 75 95 115 135 155 175


IR-4

Raw

Sig

nal

0.57

0.62

0.67

0.72

0.77

LS 9

0 R

aw S

igna

l

a-PP (20,000)

i-PP (Mw 265,000)

HDPE (115,000)

®


-0.01

0.01

0.03

0.05

0.07

0.09

35 55 75 95 115 135 155 175


-0.018

0.022

0.062

0.102

Blend of a-PP/i-PP/HDPE—Composition Mode of IR-4 Detector

a-PP

i-PP

HDPEMethylene channelMethyl channel

Ratio of the two channels is correlated to CH3/1000C

®


-4.4

-3.4

-2.4

-1.4

-0.4

0.6

1.6

-40 -10 20 50 80 110 140 170 200

Temp (C)

Hea

t fl

ow

(w

/g)

DSC of a-PP/i-PP/HDPE blend

Cocrystallization during cooling

HeatingFailed to quantify i-PP wt%No info about a-PP

HDPE 132.0oC i-PP 158.9oC

®


CRYSTAF of a-PP/i-PP/HDPE blend

0

2

4

6

8

10

12

25 35 45 55 65 75 85 95

Temperature (ºC)

De

riv

ati

ve

(d

W/d

T)

0

10

20

30

40

50

60

70

80

90

100

Cu

mu

lati

ve

(w

t%)

a-PP (expected 35.0 wt%)Measured 23.6wt%Unable to tell Mw of SF

HDPE

i-PP

Limited data point. Difficult to deconvolute

®


-1

1

3

5

7

9

11

13

20 40 60 80 100 120

Temperature (C)

Ma

ss

(d

Wf/

dT

)

0

1

2

3

4

5

6

7

Lo

gM

W

CEF of a-PP/i-PP/HDPE blend

No baseline separation between

HDPE and i-PP

a-PP HDPE

i-PP

®


Triple detector (IR/LS/DP) TGIC

AdvantagesAdvantages Provides abundant (triple detector) and unique information

regarding microstructure of polyolefins in short experimental time»CCD, Mw versus CCD, IV versus CCD, Rg versus CCD

Elimination of the cocrystallization commonly observed in CEF, CRYSTAF and TREF

»Making modeling and deconvolution of CCD distribution feasible. Bringing new opportunity to characterize new polyolefins with

more complex microstructures

®


0

0.05

0.1

0.15

0.2

0.25

-4-20246810121416

Apparent mol% C8

WF/

d(C

8 m

ol%

C8)

Comparison of TGIC with Solvent Gradient HT-LC

0

0.05

0.1

0.15

0.2

0.25

-4-20246810121416

Apparent mol% C8

WF/

d(m

ol%

C8)

Injection 1

Injection 2

Injection 3

-0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

90 100 110 120 130 140 150 160

A quick TGIC

0

0.05

0.1

0.15

0.2

0.25

-4-20246810121416

Apparent mol% C8

WF/

d(m

ol%

C8)

Injection 1

Injection 2

Injection 3

-0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

90 100 110 120 130 140 150 160

A quick TGIC

TGICHT-LC

Similar Comonomer distribution.

TCB

®


Repeatability of TGIC

-1

1

3

5

7

9

40 60 80 100 120 140 160 180


IR-4

Sig

nal 10 Consecutive injections

with different sample preps

Excellent in repeatability

Tp=134.86±0.17oCRSD=0.25%

®


Experimental Set-up

70 vial autosampler, triple detector and subambient capability

Time

Loading Loading ColumnColumn Adsorption*Adsorption* DesorptionDesorption

Final/Final/CleaningCleaning

Tem

p

Detectors (IR4-LS-DP)Pump Injector

Solv

®


• TGIC is a new technique to characterize polyolefins. Proposed mechanism is the interaction of polyolefin chains with stationary phase (column) upon temp change in a constant solvent composition

• TGIC overcomes the detector difficulty in solvent gradient HT-LC

• TGIC is a versatile technique, capable of providing comonomer composition from 0 to 100 mol% octene

• With triple detector, TGIC provides abundant information about polyolefin microstructure to compliment quadruple detector GPC

Conclusions

®

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Questions?

®


Experimental set up for finding anchoring temp of HDPE

HDPE loaded at different temp onto HYPERCARB column

Heating rate 3oC/min

80

100

120

140

160

0 5 10 15

Time (min)

Ove

n/co

lum

n Te

mp

(C) 140oC

130oC120oC

®


0.1

0.2

0.3

0.4

0.5

120 130 140 150 160 170

Oven Temp (oC)

IR-4

Raw

Sig

nal

Anchoring/desorption temp of HDPE

• Anchoring temp of HDPE in ODCB: ~137oC. Desorption temp: 147oC

• Anchoring/desorption temp depended on solvent.

• Anchoring temp is insensitive to expt parameter, but related CEF

140oC130oC120oC

®


Interaction of polymer with substrate

Chi

log

(Kp

)

po

siti

ven

egat

ive

>0.5<0.5

SUCCESS!Adsorption D

isso

lutio

n B

ound

ary

R

S

RT

HpK

)ln(

Chi

log

(Kp

)

po

siti

ven

egat

ive

>0.5<0.5

SUCCESS!Adsorption D

isso

lutio

n B

ound

ary

Chi

log

(Kp

)

Chi

log

(Kp

)

po

siti

ven

egat

ive

>0.5<0.5

SUCCESS!AdsorptionSUCCESS!Adsorption D

isso

lutio

n B

ound

ary

R

S

RT

HpK

)ln(

Documents

® ® Trademark of the Dow Chemical Company THERMAL GRADIENT INTERACTION CHROMATOGRAPHY (TGIC) FOR MICROSTRUCTURE ANALYSIS OF POLYOLEFINS Rongjuan Cong 1,