Advances In Characterization Techniques

1. Advances In Characterization Techniques Dr. Krishna Gupta Technical Director Porous Materials, Inc., USA PMI EUROPE WORK SHOP

2. Topics • Flow Porometry • Accuracy and Reproducibility • Technology for Characterization under Application Environment • Directional Porometry • Clamp-On Porometry • Flexibility to Accommodate Samples of Wide Variety of Shapes, Sizes and Porosity • Ease of Operation PMI EUROPE WORK SHOP

3. Topics • Diffusion Gas Permeametry • High Flow Gas Permeametry • Microflow liquid permeametry • High flow liquid permeametry at high temperature & high presure • Envelope surface area, average particle size & average fiber diameter analysis • Water vapor transmission rate • Permeametry PMI EUROPE WORK SHOP

4. Topics • Stainless steel sample chamber • Special design to minimize contact with mercury • Non-Mercury Intrusion Porosimetry • Sample chamber that permits mercury intrusion porosimeter to be used as non-mercury intrusion porosimeter • Water Intrusion Porosimeter • Mercury Intrusion Porosimetry PMI EUROPE WORK SHOP

5. Topics • Conclusions • Gas Adsorption PMI EUROPE WORK SHOP

6. Flow Porometry (Capillary Flow Porometry) • Design modified to minimized errors • Appropriate corrections incorporated Accuracy and Reproducibility • Most important sources of random & systematic errors identified PMI EUROPE WORK SHOP

7. Flow Porometry(Capillary Flow Porometry) Accuracy PMI EUROPE WORK SHOP

8. Flow Porometry(Capillary Flow Porometry) • Same operator • Same machine • Same wetting liquid • Same filter Repeatability • Bubble point repeated 32 times PMI EUROPE WORK SHOP

9. Flow Porometry(Capillary Flow Porometry) PMI EUROPE WORK SHOP

10. Flow Porometry(Capillary Flow Porometry) • Errors due to the use of different machines PMI EUROPE WORK SHOP

11. Flow Porometry(Capillary Flow Porometry) • Operator errors PMI EUROPE WORK SHOP

12. Arrangement for testing sample under compressive stress Technology for Characterization under Simulated Application Environment Compressive Stress • Arrangement for testing sample under compressive stress PMI EUROPE WORK SHOP

13. Technology for Characterization under Simulated Application Environment • Sample size as large as 8 inches • Programmed to apply desired stress, perform test & release stress Compressive Stress Features: • Any compressive stress up to 1000 psi (700 kPa) PMI EUROPE WORK SHOP

14. Effect of compressive stress on bubble point pore diameter Technology for Characterization under Simulated Application Environment PMI EUROPE WORK SHOP

15. Technology for Characterization under Simulated Application Environment PMI EUROPE WORK SHOP

16. Technology for Characterization under Simulated Application Environment Cyclic stress • Stress cycles are applied on sample sandwiched between two porous plates and the sample is tested during a pause in the stress cycle PMI EUROPE WORK SHOP

17. Sample chamber for cyclic compression porometer Technology for Characterization under Simulated Application Environment PMI EUROPE WORK SHOP

18. Technology for Characterization under Simulated Application Environment • Stress may be applied and released at fixed rates • Duration of cycle 10 s • Frequency adjustable by changing the duration of application of stress Features: • Any desired stress between 15 and 3000 psi PMI EUROPE WORK SHOP

19. Technology for Characterization under Simulated Application Environment • Programmed tointerrupt after specified number of cycles, wait for a predetermined length of time, measure characteristics and then continue stressing Features: PMI EUROPE WORK SHOP

20. Technology for Characterization under Simulated Application Environment • Sample can be tested any required number of times within a specified range Features: • Fully automated PMI EUROPE WORK SHOP

21. Change of bubble point pore diameter with number of stress cycles Technology for Characterization under Simulated Application Environment PMI EUROPE WORK SHOP

22. Effects of Cyclic compression on permeability Technology for Characterization under Simulated Application Environment PMI EUROPE WORK SHOP

23. Pore size of separator determined using KOH solution Technology for Characterization under Simulated Application Environment Aggressive environment PMI EUROPE WORK SHOP

24. Technology for Characterization under Simulated Application Environment Directional Porometry • In this technique, Gas is allowed to displace liquid in pores in the specified direction PMI EUROPE WORK SHOP

25. Sample chamber for determination of in-plane (x-y plane) pore structure Technology for Characterization under Simulated Application Environment PMI EUROPE WORK SHOP

26. Sample chamber for determination of pore structure in a specific direction such as x or y Technology for Characterization under Simulated Application Environment PMI EUROPE WORK SHOP

27. Technology for Characterization under Simulated Application Environment PMI EUROPE WORK SHOP

28. Typical chambers for clamp-on porometer Clamp-On Porometry • Sample chamber clamps on any desired location of sample (No need to cut sample & damage the material) PMI EUROPE WORK SHOP

29. Clamp-On Porometry • No damage to the bulk material • Test may be performed on any location in the bulk material Advantages: • Very fast PMI EUROPE WORK SHOP

30. Flexibility to Accommodate a Wide Variety of Sample Shape, Size and Porosity • Plates Shapes: • Sheets • Hollow Fibers • Pen tips • Discs • Cartridges • Rods • Diapers • Tubes • Odd shapes • Powders • Nanofibers PMI EUROPE WORK SHOP

31. Flexibility to Accommodate a Wide Variety of Sample Shape, Size and Porosity • 8 inch wafers • Two feet cartridges • Entire diaper Size: • Micron size biomedical devices PMI EUROPE WORK SHOP

32. Flexibility to Accommodate a Wide Variety of Sample Shape, Size and Porosity Materials: • Ceramics • Nonwovens • Metals • Composites • Textiles • Gels • Sponges • Hydrogels PMI EUROPE WORK SHOP

33. Ease of Operation • Fully automated • Test execution • Data storage • Data Reduction • User friendly interface • Menu driven windows based software PMI EUROPE WORK SHOP

34. Ease of Operation • Graphical display of real time test status and results of test in progress • Many user specified formats for plotting & display of results • Minimal operator involvement PMI EUROPE WORK SHOP

35. Advanced Permeametry • Different directions; x, y and z directions, x-y plane • At elevated temperatures, high pressure & under stress • Very low or very high permeability Capability: • A wide variety of gases, liquids & strong chemicals PMI EUROPE WORK SHOP

36. Principle of diffusion permeameter Diffusion Gas Permeametry PMI EUROPE WORK SHOP

37. The PMI Diffusion Permeameter Diffusion Gas Permeameter PMI EUROPE WORK SHOP

38. Change of outlet gas pressure with time for two samples measured in the PMI Diffusion Permeameter. Diffusion Gas Permeametry (dVs/dt) = (TsVo/Tps)(dp/dt) Vs = gas flow in volume of gas at STP Vo = volume of chamber on the outlet side Flow rate < 0.75x10-4 cm3/s PMI EUROPE WORK SHOP

39. High Flow Gas Permeametry • Can measure flow rates as high as 105 cm3/s • Can test large size components • Uses actual component; Diaper, Cartridges, etc. PMI EUROPE WORK SHOP

40. PMI High Flow Gas Permeameter High Flow Gas Permeametry PMI EUROPE WORK SHOP

41. Microflow Liquid Permeametry • Ceramic discs • Membranes • Potatoes • Other vegetables & fruit • Uses a microbalance to measure small weights of displaced liquid, 10-4 cm3/s • Measures very low liquid permeability in materials PMI EUROPE WORK SHOP

42. High Flow Liquid Permeametry at High Temperatures and High Pressures • Measures high permeability of application fluids at high temperature through actual parts under compressive stress PMI EUROPE WORK SHOP

43. The PMI high pressure, high temperature and high flow liquid permeameter High Flow Liquid Permeametry at High Temperatures and High Pressures PMI EUROPE WORK SHOP

44. High Flow Liquid Permeametry at High Temperatures and High Pressures • Compressive stress on sample 300 psi • Liquid: Oil • Flow rate: 2 L/min Capability: • Temperature 100C PMI EUROPE WORK SHOP

45. The PMI Envelope Surface Area, Average Fiber Diameter and Average Particle Size Analyzer Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement PMI EUROPE WORK SHOP

46. Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Envelope Surface Area • Computes surface area from flow rate using Kozeny and Carman relation PMI EUROPE WORK SHOP

47. Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement Envelope Surface Area • [Fl/pA] ={P3/[K(1-P)2S2m]}+[ZP2p]/[(1-P)S(2ppr)1/2] F = gas flow rate in volume at average pressure, pl = thickness of sample per unit time p = pressure drop, (pi-po) p = average pressure, [(pi+po)/2], where pi is the inlet rb = bulk density of sample pressure and po is the outlet pressure ra = true density of sample A = cross-sectional area of sample m = viscosity of gas P = porosity (pore volume/total volume) = [1-(rb/ra)] p = average pressure, [(pi+po)/2], where pi is the r = density of the gas at inlet pressure and po is the outlet pressure the average pressure, p S = through pore surface area per unit volume Z = a constant. It is shown to of solid in the sample be (48/13p) K = a constant dependent on the geometry of the pores in the media. It has a value close to 5 for random pored media PMI EUROPE WORK SHOP

48. Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement • Comparison between BET and ESA Methods PMI EUROPE WORK SHOP

49. 6 d = Sr Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement d = the average particle size S = specific surface area of the sample (total Surface area/mass) r = true density of the material Average particle size • Computes from surface area assuming same size & spherical shape of particles PMI EUROPE WORK SHOP

50. Envelope Surface Area, Average Particle Size & Average Fiber Diameter Measurement • Comparison between BET and ESA Methods PMI EUROPE WORK SHOP