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Methods of Porosity Measurement and Testing
- 1. Porosity Analysis and Measurement of TextileMaterials M Mehran Ali 23-NTU-0008 Aziz Umar 23-NTU-0005
- 2. Contents: • Porosity • Importance– Benefits • Limitations • Methods of porosity Measurement (Procedure – Applications – Flaws) • Future Advancements • References
- 3. Porosity Porosity refers tothe measure of voids or pores or empty spaces within a material. Ratio of total empty area to total area Ratio of total empty volume to total volume
- 4. Importance of porosity: Benefits: • Ventilation,Air circulation, Breathability, thermal insulation, lightweight textiles, filtration applications, medical, etc. Limitations (Challenges): • Reduce properties • Reduce strength and durability • Potential for Pilling • Challenges in Waterproofing, Etc.
- 5. Methods of porosity Measurement FluidDisplacement Air permeability test CFP (Capillary flow Porometry) MIP (Mercury intrusion Porosimetry) BET (Brunauer-Emmett-Teller) Water Flow test AFM (Atomic force microscopy)
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- 7. Fluid Displacement Method Working procedure Applications in textiles Flaws Preparationand initial mass measurement Immersion in liquid Displacement measurement Calculation
- 8. Fluid Displacement Method Working procedure Applications in textiles Flaws •Filtration (Liquid Filtration, etc.) • Nonwoven Fabrics • Sportswear • Thermal Insulation
- 9. Fluid Displacement Method Working procedure Applications in textiles Flaws •Pore Size Distribution • Fluid selection • Time consuming • Temperature sensitivity • Sample Preparation sensitivity
- 10. Air Permeability Test WorkingProcedure Applications in Textiles Flaws
- 11. Air Permeability Test WorkingProcedure Applications in Textiles Flaws • Sample Preparation • Placement of sample • Expose area to air flow • Apply pressure difference • Air Flow Measurement • Calculation of Permeability
- 12. Air Permeability Test WorkingProcedure Applications in Textiles Flaws Where, • k = air permeability • Q = volume of air flow through the specimen • L = thickness of the specimen • A = area of the specimen • ΔP = pressure difference • t = time of the test
- 13. Air Permeability Test WorkingProcedure Applications in Textiles Flaws Breathability, Air circulation, Ventilation • Sportswear • Outdoor apparel • Medical Textiles (Wounds, etc.) • Home Textiles (Mattress, Pillows, Curtains, etc.) • Filtration (Air Filters, etc.) • Industrial fabrics (Uniforms, Temporary Shelters, etc.) • Automotive Textiles (Car Seats, etc.)
- 14. Air Permeability Test WorkingProcedure Applications in Textiles Flaws • Pore Size Distribution • Single Parameter Measurement • Limited Application Range
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- 16. CFP (Capillary Flow Porometry) Working procedure Applications in textiles Flaws •Sample preparation • Placement of sample • Wetting the sample • Apply gas pressure • Increase gas pressure • Measure gas flow rate • Determining Pore Sizes • Calculating Porosity • Generating Pore Size Distribution Graphs
- 17. CFP (Capillary Flow Porometry) Working procedure Applications in textiles Flaws Where, •r = average pore radius • γ = surface tension • θ = contact angle between the liquid and the solid material. • P = applied pressure. Where, • n(r) = pore size distribution function • rmin and rmax = minimum and maximum pore radii
- 18. CFP (Capillary Flow Porometry) Working procedure Applications in textiles Flaws Poresize distribution • Nonwoven Textiles • Sportswear • Filtration media • Absorbency Analysis in Towels and Diapers
- 19. CFP (Capillary Flow Porometry) Working procedure Applications in textiles Flaws •Accuracy depends on saturation • Not suitable tight weaves
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- 21. MIP (Mercury Intrusion Porosimetry) Working Procedure Applications in Textiles Flaws •Sample preparation • Evacuation of air • Mercury filling • Pressure application • Volume measurement
- 22. MIP (Mercury Intrusion Porosimetry) Working Procedure Applications in Textiles Flaws •Pore Size Distribution • Analysis of Nonwoven Fabrics • Medical Textiles • Development of Smart Textiles • Understanding Thermal Insulation
- 23. MIP (Mercury Intrusion Porosimetry) Working Procedure Applications in Textiles Flaws •Damage to sample • Micro pores may not detect • Damage structure • Mercury hazards
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- 25. BET (Brunauer-Emmett-Teller) Working Procedure Applications in Textiles Flaws •Sample Preparation • Place in the instrument • Remove any gas or moisture • Introduce adsorptive gas (Nitrogen) • Increase pressure of gas (forms Monolayer of gas) • Further increase pressure (forms Multilayer of gas) • Calculate porosity (by formula)
- 26. BET (Brunauer-Emmett-Teller) Working Procedure Applications in Textiles Flaws Formula Where, •Vm = Volume of gas adsorbed at the monolayer coverage • ρ = Density of the adsorbed gas • m = Mass of the material • ρmaterial = density of material
- 27. BET (Brunauer-Emmett-Teller) Working Procedure Applications in Textiles Flaws •Fiber surface area • Fiber surface analysis • Fabric porosity • Adsorption characteristics • Coating efficiency (Finishes effects) • Medical textiles • Quality control
- 28. BET (Brunauer-Emmett-Teller) Working Procedure Applications in Textiles Flaws •Temperature and Pressure Sensitivity • Limited Information on Pore Size Distribution • Applicability to Homogeneous Materials • Sample Pretreatment Challenges
- 29. Water Flow test: WorkingProcedure Applications in Textiles Flaws
- 30. Water Flow test: WorkingProcedure Applications in Textiles Flaws • Sample Preparation • Mounting the Sample • Water Application • Measurement of Water Flow • Calculation of Porosity
- 31. Water Flow test: WorkingProcedure Applications in Textiles Flaws • Hygiene Products • Outdoor Apparel • Medical Textiles • Filtration Materials • Sportswear • Quality Control
- 32. Water Flow test: WorkingProcedure Applications in Textiles Flaws • Sensitivity to Test Conditions • Not suitable for repellent coatings • Limited Information on Pore Size Distribution • Inability to Distinguish Between Open and Closed Pores
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- 34. AFM (Atomic Force Microscopy) Working Procedure Applications inTextiles Flaws Sample Preparation Scanning Process Topographical Imaging
- 35. AFM (Atomic Force Microscopy) Working Procedure Applications inTextiles Flaws • Pore Size Estimation • Surface Morphology • Surface Roughness • Visualization of Fiber Networks • Defects and Irregularities • Nanostructure Analysis
- 36. AFM (Atomic Force Microscopy) Working Procedure Applications inTextiles Flaws • Small Field of View • Time-Consuming • Complexity for Inexperienced Users • Cost
- 37. Recent Advancements in PorosityAnalysis Micro-Computed Tomography (µCT): Provides 3D images of a material's internal structure with high resolution. Nuclear Magnetic Resonance (NMR) Imaging: Create detailed images of the internal pore structure. Focused Ion Beam SEM (FIB-SEM): Combines a focused ion beam to mill the sample with SEM to image the surface.
- 38. Future Trends inPorosity Analysis Anticipated Technological Advancements: Integrated Sensing Technologies Advanced Material Synthesis AI-Driven Predictive Modeling Non-Invasive Imaging Techniques Potential Industry Transformations: Customization at Scale Sustainability Focus Smart and Functional Textiles
- 39. References: • www.sciencedirect.com/science/article/abs/pii/S235249282302250X • journals.sagepub.com/doi/abs/10.1177/0040517506065892 •www.micromeritics.com/Repository/Files/Mercury_Porosimetry_Theory_poster. pdf • citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=cd3ba8c9eebd0ef50 703aadb310538a6bb3d4211 • www.tandfonline.com/doi/abs/10.1080/00405000.2011.597567 • www.mdpi.com/2073-4360/13/3/408 • www.tandfonline.com/doi/abs/10.1080/00405000.2017.1423005 • www.emerald.com/insight/content/doi/10.1108/09556220110396533/full/html • www.degruyter.com/document/doi/10.1515/jiip-2013-0084/html