Predicting Polyolefin Foamability Using Melt Rheology

Predicting Polyolefin Predicting Polyolefin Foamability UsingFoamability Using

Melt Rheology Melt Rheology

Associated Polymer LabsAssociated Polymer Labs

Presented by Jim ZwynenburgPresented by Jim Zwynenburg

AgendaAgenda

Define Rheology Test Resulting Data Converting Data Plots Interpretations Examples Remember to Remember

Associated Polymer Labs www.testplastic.com2

DefinitionsDefinitions

Rheology Rheo means Flow Ology means the

study of

The Study of Flow

Melt Strength Is a property of the

polymer melt which indicates its ability to withstand drawing without breaking.

Associated Polymer Labs www.testplastic.com

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ASTM D-4440ASTM D-4440

Standard Test Method for Plastics: Dynamic Mechanical Properties Melt RheologyStandard Test Method for Plastics: Dynamic Mechanical Properties Melt Rheology

Frequency Sweep at 190C

Temperature Ramp from 140C-230C for Polyethylene

Temperature Ramp from 180C-260C for Polypropylene

Rheology Test Sensitivity Increases with Rheology Test Sensitivity Increases with Decreasing FrequencyDecreasing Frequency


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120.0 130.0 140.0 150.0 160.0 170.0 180.0 190.0 200.0 210.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Temp [°C]

ta

n_

de

lta (

)

[ ]Tan delta verses Temp

C:\RSIOrche600\Data 2000\June\RSI Orchestrator Document.RSD

ISO 6721-10ASTM D4440-95a

tan_delta Tan delta v erses Temp Westlake EF606, TR 100 rads, 200-130C Westlake EF606, TR 10 rads, 200-130C Westlake EF606, TR 1.0 rads, 200-130C Westlake EF606, TR 0.1 rads, 200-130C

100 rads/sec

10 rads/sec

1.0 rads/sec

0.1 rads/sec

Rheology Lab for Solids and MeltsRheology Lab for Solids and Melts


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Typical Data from Temperature RampTypical Data from Temperature Ramp


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Temp (C) G' (Pa) G" (Pa) Tan-deltaEta* (Pa-s)

139.7 16904 14605 0.86399 3557144.0 16320 14210 0.87075 3446149.5 15503 13740 0.88627 3299154.9 14704 13290 0.90385 3156160.0 13926 12875 0.92448 3020

165.4 13127 12451 0.94848 2881170.1 12405 12046 0.97107 2754175.0 11645 11609 0.99693 2618180.0 10909 11188 1.0255 2488185.4 10093 10667 1.0568 2338190.1 9427 10242 1.0864 2217195.0 8741 9769 1.1177 2087200.4 8005 9241 1.1545 1947205.0 7430 8823 1.1875 1837210.1 6823 8343 1.2229 1716215.5 6217 7856 1.2636 1595220.0 5757 7465 1.2967 1501225.1 5256 7040 1.3395 1399230.5 4773 6603 1.3833 1297

Rheology Plot 1Rheology Plot 1


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130.0 140.0 150.0 160.0 170.0 180.0 190.0 200.0 210.0 220.0 230.0 240.0

103

104

105

103

104

Temp [°C]

G

' ()

[P

a]

G

" (

) [P

a] E

ta* (

) [P

a-s]

Best Low Density Polyethylene for Foam

G' / G" Crossover Point:(175.58,1.156x104)Data: Eta*(Temp) [1..19] (19 pts) Note: o = 4393.7 Model: Ellis Model Eqn: c1/(1+(x/c2)

(c3-1)) Fit Error: 0.9999 3 Coefficients: 4393.7 190.61 5.5729

Converted Data Converted Data


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Temp (C) G' (Pa) G" (Pa) Tan-deltaEta* (Pa-s)

Torque (g/cm)

Phase Angle

Log tan-delta

Log Eta* (Pa-s)

139.7 16904 14605 0.86399 3557 67.162 40.827 -0.063 3.551144.0 16320 14210 0.87075 3446 67.164 41.048 -0.060 3.537149.5 15503 13740 0.88627 3299 67.167 41.55 -0.052 3.518154.9 14704 13290 0.90385 3156 67.169 42.109 -0.044 3.499160.0 13926 12875 0.92448 3020 67.172 42.753 -0.034 3.480

165.4 13127 12451 0.94848 2881 56.363 43.485 -0.023 3.460170.1 12405 12046 0.97107 2754 56.366 44.159 -0.013 3.440175.0 11645 11609 0.99693 2618 56.368 44.912 -0.001 3.418180.0 10909 11188 1.0255 2488 56.371 45.722 0.011 3.396185.4 10093 10667 1.0568 2338 47.202 46.583 0.024 3.369190.1 9427 10242 1.0864 2217 47.204 47.372 0.036 3.346195.0 8741 9769 1.1177 2087 47.207 48.18 0.048 3.320200.4 8005 9241 1.1545 1947 40.223 49.101 0.062 3.289205.0 7430 8823 1.1875 1837 40.226 49.899 0.075 3.264210.1 6823 8343 1.2229 1716 40.229 50.725 0.087 3.235215.5 6217 7856 1.2636 1595 33.753 51.642 0.102 3.203220.0 5757 7465 1.2967 1501 33.756 52.362 0.113 3.176225.1 5256 7040 1.3395 1399 33.759 53.256 0.127 3.146230.5 4773 6603 1.3833 1297 28.089 54.136 0.141 3.113

Plotting DataPlotting Data

Tan-Delta (G”/G’) Converted into log.

Fractions (less than one, become negative numbers)

Plot on Linear Scale

Eta* (Complex Viscosity) converted into log.

Decimal place becomes the first number, example 4000Pa-sec is 4.0

Plot on Linear Scale


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Log tan-delta

-0.100

-0.050

0.000

0.050

0.100

0.150

0.200

3.000 3.100 3.200 3.300 3.400 3.500 3.600

Log Viscosity (Eta*)

Log

Tan-

delta

(G"/

G')

Temp (C)230225220215210205200195190185180175170165160155150145140



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2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8-0.2

-0.15

-0.1

-0.05

0.0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

Log Viscosity [ Pascal-sec]

Log T

an-

delta (

) [ (G

"/G

')]

Best Low Density Polyethylene for Foam

230C

140C

Low TemperatureHigher ViscosityGreater Melt Elasticity and Strength

Higher TemperatureLower ViscosityLow Melt Elasticity and No Strength

Low Melt Elasticity and StrengthLow ViscosityHigh Density Foam Only

Polystyrene AreaHigh Eleasiciaty and Melt StrengthHigh Viscosity

Important Factors; 1) Slope2) Length3) Shape


3.0 3.5 4.0 4.5 5.0 5.5 6.0-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Log Eta* [ ]

Lo

g ta

n de

lta

()

[ ]

Polyolefin Foaming Window

LDPE

LLDPE

Polypropylene

PolyStyreneHMS PP

Branched LDPE

HDPE

High Melt Strength

Low Melt Strength

Every Polyolefin has a Unique Curve

Fingerprint The Resin

Know the response of the polymer

Imagine The Possibilities


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Example 1, Using Recycled ResinExample 1, Using Recycled Resin

Recycled content appears to separate at higher temperatures


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2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8-0.2

-0.15

-0.1

-0.05

0.0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6


Log

Tan

-del

ta

()

[ (

G"/

G')]

4 PCF Foam

Log Tan-delta 4 PCF Foam 4 PCF Foam with Recycled Resin

Example 2, Blending VerticallyExample 2, Blending Vertically

To blend Polyolefins,

Use the WZ Theorem: geometric averaging of the viscosities produces the new blended viscosity.


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2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8-0.2

-0.15

-0.1

-0.05

0.0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6


Log

Tan

-del

ta

()

[ (

G"/

G')]

Blending Polymers; Equistar NA957, NA940, 75/25 Blend

Fractional MeltEquistar NA 940

Equistar NA 957

Blend 75%/25%

Blending Rule1 + 2 = 3

Example 3;Example 3; Blending is as easy as 1,2,3 Blending is as easy as 1,2,3


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2.9 3.1 3.3 3.5 3.7 3.9-0.2

-0.06667

0.06667

0.2

0.3333

0.4667

0.6

Log Eta* [Pa-s]

Log tan d

elta (

) [ ]

125% / 75%

50% / 50%

75% / 25%

PelletsLLDPE Mixed (Post Industrial)

Log tan delta LDPE 25% LLDPE 75% LLDPE Mix LDPE 75% LLDPE 25% LDPE 50% LLDPE 50% Reprocessed LDPE Virgin LDPE

Virgin LDPE

Reprocessed LDPE

Hidden Information

Remember to RememberRemember to Remember

Polyolefins viscosity is 1+2=3 Testing takes one hour Measure and Know the Resin Properties Applies to recycled, fractional melts, additives,

rheology modifiers, crosslinking agents, etc New Models are available for all thermoplastic

materials Cost Savings

Associated Polymer Labs

www.testplastic.com17

The EndThe End

I’m Grateful to share my experience and knowledge

Extra Special Thanks to Gary Wilkes

Special Thanks to Stephen Driscolle, University of Massachusetts

Jay Patel, Patel Scientific

Members of the Foams Committee for accepting my paper

Everyone present for listening


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Documents

Predicting Polyolefin Foamability Using Melt Rheology