Predicting Polyolefin Foamability Using Melt Rheology Associated Polymer Labs Presented by Jim Zwynenburg Agenda Define Rheology Test Resulting Data Converting Data Plots Interpretations Examples Remember to Remember 2 Associated Polymer Labs www.testplastic.com Definitions Rheology Rheo means Flow Ology means the study of Melt Strength The Study of Flow Associated Polymer Labs www.testplastic.com Is a property of the polymer melt which indicates its ability to withstand drawing without breaking. 3 ASTM D-4440 Standard 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 Associated Polymer Labs www.testplastic.com 4 Rheology Test Sensitivity Increases with Decreasing Frequency Tan delta verses Temp 3.5 3.0 C:\RSIOrche600\Data 2000\June\RSI Orchestrator Document.RSD 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 0.1 rads/sec ) 2.5 tan_delta ( [] 2.0 1.5 1.0 rads/sec 1.0 10 rads/sec 0.5 100 rads/sec 0.0 120.0 130.0 140.0 150.0 160.0 170.0 180.0 190.0 200.0 210.0 Tem p [°C] ISO 6721-10 ASTM D4440-95a Associated Polymer Labs www.testplastic.com 5 Rheology Lab for Solids and Melts Associated Polymer Labs www.testplastic.com 6 Typical Data from Temperature Ramp Temp (C) Eta* G' (Pa) G" (Pa) Tan-delta (Pa-s) 139.7 16904 14605 0.86399 3557 144.0 16320 14210 0.87075 3446 149.5 15503 13740 0.88627 3299 154.9 14704 13290 0.90385 3156 160.0 13926 12875 0.92448 3020 165.4 170.1 175.0 180.0 185.4 190.1 195.0 200.4 205.0 210.1 215.5 220.0 225.1 230.5 13127 12405 11645 10909 10093 9427 8741 8005 7430 6823 6217 5757 5256 4773 12451 12046 11609 11188 10667 10242 9769 9241 8823 8343 7856 7465 7040 6603 0.94848 0.97107 0.99693 1.0255 1.0568 1.0864 1.1177 1.1545 1.1875 1.2229 1.2636 1.2967 1.3395 1.3833 2881 2754 2618 2488 2338 2217 2087 1947 1837 1716 1595 1501 1399 1297 Associated Polymer Labs www.testplastic.com 7 Rheology Plot 1 Best Low Density Polyethylene for Foam 10 5 10 Data: Eta*(Temp) [1..19] (19 pts) Note: o = 4393.7 Model: Ellis Model (c -1) Eqn: c1/(1+(x/c 2) 3 ) Fit Error: ) 4 G' / G" Crossover Point:(175.58,1.156x10 ) 0.9999 3 Coefficients: 4393.7 190.61 5.5729 Eta * ( [ Pa -s] G"( [ Pa ] 4 4 ) 10 G' ( [ Pa ] ) 10 3 130.0 10 140.0 150.0 160.0 170.0 180.0 190.0 200.0 210.0 220.0 230.0 3 240.0 Temp [°C] Associated Polymer Labs www.testplastic.com 8 Converted Data Temp (C) Eta* Torque Phase Log tan- Log Eta* G' (Pa) G" (Pa) Tan-delta (Pa-s) (g/cm) Angle delta (Pa-s) 139.7 16904 14605 0.86399 3557 67.162 40.827 -0.063 3.551 144.0 16320 14210 0.87075 3446 67.164 41.048 -0.060 3.537 149.5 15503 13740 0.88627 3299 67.167 41.55 -0.052 3.518 154.9 14704 13290 0.90385 3156 67.169 42.109 -0.044 3.499 160.0 13926 12875 0.92448 3020 67.172 42.753 -0.034 3.480 165.4 170.1 175.0 180.0 185.4 190.1 195.0 200.4 205.0 210.1 215.5 220.0 225.1 230.5 13127 12405 11645 10909 10093 9427 8741 8005 7430 6823 6217 5757 5256 4773 12451 12046 11609 11188 10667 10242 9769 9241 8823 8343 7856 7465 7040 6603 0.94848 0.97107 0.99693 1.0255 1.0568 1.0864 1.1177 1.1545 1.1875 1.2229 1.2636 1.2967 1.3395 1.3833 2881 2754 2618 2488 2338 2217 2087 1947 1837 1716 1595 1501 1399 1297 56.363 56.366 56.368 56.371 47.202 47.204 47.207 40.223 40.226 40.229 33.753 33.756 33.759 28.089 Associated Polymer Labs www.testplastic.com 43.485 44.159 44.912 45.722 46.583 47.372 48.18 49.101 49.899 50.725 51.642 52.362 53.256 54.136 -0.023 -0.013 -0.001 0.011 0.024 0.036 0.048 0.062 0.075 0.087 0.102 0.113 0.127 0.141 3.460 3.440 3.418 3.396 3.369 3.346 3.320 3.289 3.264 3.235 3.203 3.176 3.146 3.113 9 Plotting 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 Associated Polymer Labs www.testplastic.com 10 Rheology Plot 2 Log tan-delta 0.200 Log Tan-delta (G"/G') Temp (C) 230 225 220 215 210 205 200 195 190 185 180 175 170 165 160 155 150 145 140 0.150 0.100 0.050 0.000 3.000 -0.050 3.100 3.200 3.300 3.400 3.500 3.600 -0.100 Log Viscosity (Eta*) Associated Polymer Labs www.testplastic.com 11 Rheology Plot 3 Best Low Density Polyethylene for Foam 0.6 0.55 Low Melt Elasticity and Strength Low Viscosity High Density Foam Only 0.5 0.45 ) 0.4 0.35 Log Tan -delta ( [ ( G "/ G ')] 0.3 0.25 Higher Temperature Low er Viscosity Low Melt Elasticity and No Strength 0.2 230C 0.15 Important Factors; 1) Slope 0.1 2) Length 3) Shape 0.05 0.0 -0.05 140C -0.1 Low Temperature Higher Viscosity Greater Melt Elasticity and Strength -0.15 Polystyrene Area High Eleasiciaty and Melt Strength High Viscosity -0.2 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 Log Viscosity [ Pascal-sec] Associated Polymer Labs www.testplastic.com 12 Rheology Plot 4 Polyolefin Foaming Window 1.0 LDPE 0.9 Low Melt Strength 0.8 LLDPE ) 0.7 Polypropylene 0.6 Log tan delta [] ( 0.5 0.4 0.3 Branched LDPE 0.2 HMS PP 0.1 HDPE PolyStyrene 0.0 High Melt Strength -0.1 Every Polyolefin has a Unique Curve Fingerprint The Resin Know the response of the polymer Imagine The Possibilities -0.2 3.0 3.5 4.0 4.5 5.0 5.5 6.0 Log Eta* [ ] Associated Polymer Labs www.testplastic.com 13 Example 1, Using Recycled Resin 4 PCF Foam 0.6 0.55 Log Tan-delta 4 PCF Foam 4 PCF Foam with Recycled Resin 0.5 0.45 ) 0.4 0.35 Log Tan -delta ( [ ( G "/ G ')] 0.3 0.25 Recycled content appears to separate at higher temperatures 0.2 0.15 0.1 0.05 0.0 -0.05 -0.1 -0.15 -0.2 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 Log Viscosity [ Pascal-sec] Associated Polymer Labs www.testplastic.com 14 Example 2, Blending Vertically Blending Polymers; Equistar NA957, NA940, 75/25 Blend 0.6 0.55 Blending Rule 1+2=3 0.5 0.45 ) 0.4 0.35 Log Tan -delta ( [ ( G "/ G ')] 0.3 0.25 0.2 Equistar NA 957 0.15 0.1 0.05 Blend 75%/25% 0.0 -0.05 Fractional Melt Equistar NA 940 -0.1 To blend Polyolefins, Use the WZ Theorem: geometric averaging of the viscosities produces the new blended viscosity. -0.15 -0.2 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 Log Viscosity [ Pascal-sec] Associated Polymer Labs www.testplastic.com 15 Example 3; Blending is as easy as 1,2,3 0.6 Log tan delta LDPE 25% LLDPE 75% 0.4667 LLDPE Mix LDPE 75% LLDPE 25% LDPE 50% LLDPE 50% Reprocessed LDPE ) Virgin LDPE 0.3333 Log tan delta [] ( LLDPE Mix ed (Post Industrial) Pellets 0.2 25% / 75% 1 0.06667 Virgin LDPE 50% / 50% 75% / 25% Reprocessed LDPE -0.06667 -0.2 2.9 Hidden Information 3.1 3.3 3.5 3.7 3.9 Log Eta* [Pa-s] Associated Polymer Labs www.testplastic.com 16 Remember 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.com 17 The 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 Associated Polymer Labs www.testplastic.com 18