1. 1 Harald Pasch SASOL Chair of Analytical Polymer Science Department of Chemistry and Polymer Science, University of Stellenbosch, South Africa Advanced Fractionation Techniques for Complex Polyolefins

2. 2 Polyolefin Analysis Complex Structures New Copolymers New Applications Fractionation Techniques ? HT-SECTREF CRYSTAF Chemical composition Molecular size

3. 3 Polyolefins – The Most Common Polymers polyethylene polypropylene Where are the problems ?

4. 4 Narrower PDI (Metallocene) Broader PDI (Ziegler-Natta) Polyolefins just CH, CH 2 and CH 3.... ????? Isotactic polypropylene (high crystallinity) Syndiotactic polypropylene Atactic polypropylene (low crystallinity)

5. 5 1 Molecular structure MM,MMD SCB distribution SCB content Instrumentation required HT-SEC CRYSTAF, TREF DSC NMR, FTIR 2 Morphology Crystal size, crystal size distribution tie molecules interfacial order Instrumentation required DSC, DMA NMR, Microscopy AFM, SEM 3 Physical Properties haze,gloss, clarity, tear strength, tensile strength,impact strength Instrumentation required Different test equipment Polyolefins just CH, CH 2 and CH 3.... ?????

6. 6 Branch type influences the crystal structure Distribution of the branches ??? Structures LDPE LLDPE HDPE Density 0.935 0.929 -0.945 0.940 - 0.965 Why does chain structure influence properties?

7. 7 Results: SEM Change in Crystal Morphology as a Result of Blending LDPE 60% LDPE + 40% Plastomer poly(ethylene-1-octene)

8. 8 Molar Mass Analysis

9. 9 High-Temperature SEC Polymer Labs Model PL GPC 220 Stationary phase: Cross-linked PS Mobile phase: Trichlorobenzene Temperature: 140 o C Calibration: PS, PE Detectors: RI, ELSD, IR, LS, Vis

10. 10 HT-SEC and FTIR of an Oxidized Polyethylene ?

11. 11 Universal LC-FTIR Coupling LC- Transform FTIR spectrometerseries of spectra pump + injector RI-detector HPLC / GPC Separation Identification

12. 12 SEC-FTIR of an Ethylene-Methacrylic Acid Copolymer

13. 13 SEC-FTIR Analysis of a Polyolefin Blend

14. 14 Separation by Crystallizability: Chemical Heterogeneity Temperature Rising Elution Fractionation (TREF) Crystallization Analysis Fractionation (CRYSTAF)  separation with regard to chemical composition HT-SEC CRYSTAF TREF

15. 15 Based on Flory-Huggins expression for polymer- diluent mixtures diluent: solvent, comonomer melting point depression is a function of non- crystallizable comonomer content chemical composition separation = separation by crystallizability Separation by Crystallizability: Chemical Heterogeneity

16. 16 Temperature Rising Elution Fractionation

17. 17 The slow cooling rate is the most important factor in achieving good separation The slow cooling rate minimizes the effects of co-crystallization and molar mass influences. Typical cooling rates would be about 2°C/hour It takes about 2-3 days to cool!! TREF Separation Mechanism

18. 18 Comparison of typical LLDPE and LDPE Temperature Rising Elution Fractionation

19. 19 Hypothetical samples with same MMD and crystallinity distribution but different dependency on each distribution Temperature Rising Elution Fractionation

20. 20 Automatic Cross-Fractionation System TREF-SEC S. Nakano, Y. Goto, J. Appl. Polym. Sci. 26 (1981) 4217 Temperature Rising Elution Fractionation

21. 21 TREF-SEC Analysis of a Blend of Two Polyethylenes S. Nakano, Y. Goto, J. Appl. Polym. Sci. 26 (1981) 4217 Temperature Rising Elution Fractionation

22. 22 IR detector 2030405060708090 0 2 4 6 Temperature [°C] dW/dT 0 20 40 60 80 100 W [%] Crystallization Analysis Fractionation

23. 23 Crystallization Analysis Fractionation

24. 24 Crystallization Analysis Fractionation Typical temperature cycle Typical crystallization curve

25. 25 Crystallization Analysis Fractionation Comparison of TREF and CRYSTAF Crystaf analysis of a PP blend

26. 26 CRYSTAF: Analysis of Copolymers and Blends HDPE HDPE/LDPE 4:96 HDPE/PP 50 : 50 LLDPE

27. 27 Propene-  -Olefin Copolymers Propene-Octene Propene-Octadecene CRYSTAF: Analysis of Copolymers and Blends

28. 28 CRYSTAF (in particular when coupled to IR sensor) excellent technique but very time consuming Fast and selective techniques are required liquid chromatography is a good candidate Polyolefins are soluble only at high temperatures unconventional stationary and mobile phases ???

29. 29 Elution Behaviour of Polyolefins in High Temperature Chromatography (HT-HPLC) Using Interactive Stationary Phases polyolefin must dissolve in the mobile phase screening of solubility polyolefin must interact with the phase system screening of mobile and stationary phases

30. 30 Solvents and Columns Decaline Trichlorobenzene Cyclohexanone Dimethylformamide normal phase systems: SiO 2 (ZrO 2, TiO 2, Al 2 O 3 ) reversed phase systems: Diol…CN…Phenyl…C 8 … C 18 polarity

31. 31 Screening of Stationary Phases for HT-HPLC Stationary phase: dimethylsiloxane- modified silica gel Benzylalcohol x Cyclohexylacetate  DMF  Cyclohexanone

32. 32 Stationary phase: dimethylsiloxane-modified silica gel, solvent: TCB mobile phase: EGMBE Limiting conditions with regard to PE ( ) SEC conditions with regard to PP (  ) Screening of Stationary Phases for HT-HPLC

33. 33 Stationary phase: dimethylsiloxane-modified silica gel, solvent: TCB mobile phase: EGMBE PP 36k + PE 34k PP 57k + PE 66k PP 438k + PE 500k PP: SEC PE: Limiting conditions Screening of Stationary Phases for HT-HPLC

34. 34 Analysis of PE-PMMA Block Copolymers: SEC and FTIR Multimodal distribution blend or copolymer ? MMA and ethylene units can be identified, but is it a copolymer or a polymer blend ? PEPMMA Chemical composition as a function of molar mass ? ?

35. 35 Chemical composition as a function of molar mass is visualized ! Homopolymers and copolymers can be identified ! PE PMMA PE PE-b-PMMA Analysis of PE-PMMA Block Copolymers: Coupled SEC-FTIR

36. 36 What about interaction chromatography ? SEC LC-CC molar mass separation chemical composition separation Analysis of PE-PMMA Block Copolymers

37. 37 PEPMMA PE-b-PMMA Column: Nucleosil 300 C 18 Temperature: 140  C Mobile phase: gradient from100 % DMF to 100 % TCB Analysis of PE-PMMA Block Copolymers: Gradient HPLC

38. 38 PE PMMA PE-b-PMMA ---- PMMA 1730 cm -1 ----- PE 720 cm -1 High-Temperature Gradient HPLC as a New Tool for the Analysis of Olefin Copolymers Analysis of PE-PMMA Block Copolymers: Gradient HPLC-FTIR

39. 39 Polymer Labs‘ High-Temperature Gradient HPLC System

40. 40 Separation System for PE-PP Blends Time [min] signal % TCB PP M PE

41. 41 Separation System for PE-PP Blends column: Nucleosil 500 mobile phase: EGMBE-TCB T: 140 o C detector: ELSD sample solvent: TCB PP PE EP copolymer with 48% ethylene ethylene-rich propylene-rich PP L.-C. Heinz, H. Pasch, High-Temperature Gradient HPLC for the Separation of Polyethylene-Polypropylene Blends.Polymer 46 (2005) 12040

42. 42 Separation System for EVA Copolymers stationary phase: silica gel mobile phase: gradient of decaline-cyclohexanone PVAc PE A. Albrecht, R. Brüll, T. Macko, H. Pasch: Separation of Ethylene-Vinyl Acetate Copolymers by High-Temperature Gradient Liquid Chromatography. Macromolecules 40 (2007) 5545

43. 43 Separation of Polyolefins by Tacticity stationary phase: carbon-based mobile phase: gradient of 1-decanol-TCB

44. 44 Schematic Protocol for 2D Separations

45. 45 Degasser Pump Degasser Pump Injector HPLC Column Two-Dimensional Chromatography (HPLC vs. SEC) Detector Data Processing Waste 1. Dimension: HPLC/LCCC 2. Dimension: GPC SEC Column

46. 46 High-Temperature 2D-HPLC in Stellenbosch

47. 47 Chromatographic conditions: Stationary phase: Hypercarb Mobile phase: gradient of decanol-TCB Operating temperature: 160 o C High-Temperature 2D-HPLC Ginsburg, A., Macko, T., Dolle, V., Bruell, R., Europ. Polym. J. 47 (2011) 319-329

48. 48 High-Temperature LC-NMR

49. 49 HT Stop-flow valve ELSD Transfer line Transfer line HT-SEC High-Temperature LC-NMR

50. 50 polyethylene polymethyl methacrylate copolymer EtMMA

51. 51 On-flow High-Temperature SEC-NMR TCB Impurities T=130°C

52. 52 PE M n =1.100 Et-MMA M n =10.600 PMMA M n =263.000 Solvent subtraction of impurities T=130°C flow rate 0.5mL/min, conc. 2+2+2 mg/mL, 300 µL injection volume, 5 Waters columns, 24 scans per FID, 1.24s repetition delay On-flow High-Temperature SEC-NMR

53. 53 1 H traces of the on-flow run On-flow High-Temperature SEC-NMR

54. 54 on-flow HT-SEC-NMR of PE-PMMA Block Copolymer E MMA On-flow High-Temperature SEC-NMR