290 likes | 601 Views
Solutions for PET: Nucleating Additives for Crystallization Rate & GraftedModifiers for Impact Strength. Dr. Larry G. Bourland poly VISIONS, INC 25 Devco Drive Manchester, PA 17345. Advantages High Melting (265 o C) Temperatures Heat Resistance Low Cost Excellent Barrier. Drawbacks
E N D
Solutions for PET: Nucleating Additives for Crystallization Rate & GraftedModifiers for Impact Strength Dr. Larry G. BourlandpolyVISIONS, INC25 Devco DriveManchester, PA 17345
Advantages High Melting (265oC) Temperatures Heat Resistance Low Cost Excellent Barrier Drawbacks Degrades by Moisture Induced Chain Scission Reactions in Melt State Slow Crystallization Rate Brittle at Low Temperatures Attributes of PET
Drawbacks Degrades by Moisture Induced Chain Scission Reactions in Melt State Slow Crystallization Rate Brittle at Low Temperatures Solutions Dry Material before Processing Reactions Promote grafting of end groups Avoid Chain Scission Crystallization Rate Acceleration by Heterogeneous Nucleant Retardation by Homogeneous Additives Impact modify with Rubber compatibilized using PET-g-Rubber Solutions to Drawbacks
Presentation Topics • Melt Rheology of PET & PET Alloys • Vacuum Drying • Testing Procedures • Melt Flow Rate (MFR) vs PET IV • Capillary Melt Viscosity • ( h vs. g ) Evidence for reaction • ( h vs. time) Evidence for completed reaction • Control of Crystallization Rate • Mineral Heterogeneous Nucleants • Reactive Degradation of PET • Efficiencies of Rate Acceleration • Miscible Polymers Homogeneous Nucleants • Reaction or Miscibility? • Efficiency of Rate Retardation • Impact Strength at low temperatures • Evidence for PET End Group Reaction with modified rubber to produce PET-g-Rubber additive • PET-graft-Rubber additives compatibilizes Rubber with PET --> enhanced impact strengths at low temperatures
Melt RheologySample Drying • Measurements • Capillary Rheometry (Viscosity vs. Shear Rate) Data Comparison • Viscosity at Common Shear Rate (200 sec-1)
Melt Flow Conditions for PET Modifications to ASTM Procedures range of 1-10 (g/10 min) for PET products: • Test Temperature 285oC • Orifice Diameter 0.040 inch • Weight Load 3.7 Kg • Sample Load Time <1 minute • Drying Requirements < 20 ppm or (time at temperature to achieve constant viscosity)
Melt RheologyGrafting Reactions Capillary Rheology Measurements • Extent of Reaction: • Viscosity vs. Time • Evidence for Reaction: • Viscosity vs. Shear Rate
Melt Viscosity vs. TimeCompletion of Reaction: PET-graft-Rubber
Accelerating PET Crystallization Heterogeneous Nucleants for PET: Type Nucleating Reactive Talc Yes Yes CaCO3 Yes Yes BaSO4 Yes Yes Carbon Black Yes No Silicates No No Mica No No
Retarding PET Crystallization Miscible Additives Retard Crystallization • Homogeneous Effect • Some Waxes and Plasticizer • Selected Polycarbonates • Enhanced Potential Reaction with PET
Impact Modification of PET Rubbery Additives alone are ineffective: • Immiscible with PET • Poor Interfacial Contact • Limited Stress Transfer to Rubber PET/Rubber Interfacial compatibilization with Graft Copolymer is effective: • Primary Rubber EMAC Copolymer • Graft Compatibilizer PET-g-EMAC • Homopolymer Matrix 0.95 IV PET
Conclusions PET Melt Rheology • Reliable Methodology • MFR Correlates with IV for pure PET Resins • Melt Flow of PET Alloys • Reactivity of PET with Minerals • Reactivity of PET with Functionalized Polymers: • Reaction Exists • Extent of Reaction • Stability of Reactants
Conclusions PET Additives Crystallization Rate Control • Accelerate Rate of PET Crystallization • PET / Mineral Masterbatches • Heterogeneous Nucleation • Retard Rate of PET Crystallization • PET / PC Alloys • Homogeneous Effect Improve Impact Strength of PET: • PET-g-Rubber Modifier by Reactive Extrusion with Functionalized Rubber • Compatibilizer for PET / Rubber Interface • Improve Impact Strength of PET at Ambient and Low Temperatures