Now You Know Characterization of Pore Structure in Textiles (Part-2)

Characterization of Pore Structure in Textiles (Part-2)

Arpita Kothari
M. Tech. Scholar
Department of Textile Technology,
NIT Jalandhar, India
Cell: +91- 7837-696041
Email: geniousarpita@gmail.com

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3. Pore characteristics and their application in various industries:
Different pore characteristics have their own utility in different applications which are listed below in table no. 2: [7]

Table 2: Importance of pore characteristics in various fields

Application	Required pore characteristics
Arterial support	Pore diameter Pore distribution Pore volume Burst pressure
Apparel	Pore size Break through volume Vapour permeability
Tissue growth and culture	Pore diameter Pore distribution Liquid permeability
Household and clothing	Pore size Pore volume Pore distribution Break through pore Vapour transmission Gas transmission
Filtration	Pore size Pore distribution Liquid permeability Gas permeability Pore surface area Temperature effect Environment effect

4. Characterization techniques:
The techniques used for characterizing the pore structure are described below in table no. 3: [5]

Table 3: Techniques used for measurement of characterization of pore

Measurement techniques Instrument
Porometry	Capillary flow porometer Compression porometer Integrity analyser Bubble point tester Filtration media analyser Complete filter cartridge analyser Capillary condensation flow porometer Liquid-liquid porometer
Porosimetry(intrusion)	Mercury/nonmercury porosimeter
Porosimetry(extrusion)	Liquid extrusion porosimeter
Gas adsorption	BET sorptometer BET liqisorb sorptometer
Pycnometry	Gas pycnometer Mercury pycnometer

4.1.Brief study of different techniques:
Different techniques used in textiles for characterization of pore are listed below in table no.4. [5]

Table 4: different techniques with their capabilities:

Technique	Principle	Capabilities
Capillary flow porometer	Displacement of wetting liquid from pore by gas under pressure.	Mean pore size, pore size distribution, largest pore, integrity, gas permeability, envelope surface area
Compression flow porometer	Compressive stress is applied. The flow rate and pressure is measured using dry and wet samples. These data are used to calculate the effect of compressive stress on pore size and its distribution.	Pore throat diameter, Pore size distribution, Gas permeability
Integrity analyser	Gas is allowed to flow with increasing pressure and then detect the gas flow through the sample before any pore is being emptied of liquid , thus integrity is determined.	Pore size, Largest pore, Liquid permeability
Bubble point tester	Gas pressure is applied to wetting liquid.The pressure at which gas starts flow is know as bubble point.	Largest pore size
Liquid extrusion porosimeter	Measures volume of wetting liquid displaced from pores under gas pressure.	Mean pore size, Total pore volume, Liquid permeability, Pore size distribution
Gas permeameter	It is used to determine the permeability of porous solids. A gas such as air is forced to flow through the test sample.	Gas permeability
Liquid permeameter	The flow of liquid through sample is measured by the distance a column of liquid drops in relation to time and pressure.	Liquid permeability

4.2. Capabilities and limitations of techniques:
There are two techniques which are most widely accepted for measurement of pores; one is Porosimetry which can measure only porosity(pore volume and pore size distribution), another is porometry which can measure largest pore, smallest pore as well as pore size distribution. [6]

Characterization technique in table 5and 6 showing different capabilities and limitations of different pore with their pore diameter range.

Table 5: Capabilities of different technique [7]

Capability				Measurement technique
Extrusion flow porometry	Capillary condensation flow porometry		Extrusion porosimetry	Mercury intrusion porosimetry	Vacuapore	Gas adsorption
Through pore		All diameter Pore distribution Surface area Gas/liquid permeability		Largest diameter Mean flow diameter Gas permeability		Volume Volume distribution Surface area Gas permeability
Through and blind pore		All diameter Volume Volume distribution Surface area		All diameter Volume Volume distribution Surface area		All diameter Volume Volume distribution Surface area

Table 6: Limitations and pore diameter range of techniques [7]

Measurement technique
Extrusion flow porometry	Capillary condensation flow porometry	Extrusion porosimetry	Mercury intrusion porosimetry	Vacuapore	Gas adsorption
Limitations	Use of toxic material, fixed fluid, high pressure, time consuming	Use of toxic material, fixed fluid, high pressure, time consuming	Use of toxic material, fixed fluid, high pressure,	Use of toxic material, fixed fluid, high pressure, time consuming	Use of toxic material, fixed fluid, high pressure,
Pore diameter range(micron)	.013-500	.0005-.02	.05-2000	.003-500	.0003-.2