Air permeability of polyester nonwoven fabrics

Abstract

Air permeability is one of the most important properties of non-woven fabrics in many applications. This paper aims to investigate the effects of thickness, porosity and density on the air permeability of needle-punched non-woven fabrics and compare the experimental values with two models which are based on hydraulic radius theory and drag theory, respectively. The air permeability of the samples was measured by an air permeability tester FX3300. The results showed that the air permeability of non-woven fabrics decreased with the increase in thickness and density of samples, increased with the increase of porosity, and the air permeability was not directly proportional to the pressure gradient. Meanwhile, the prediction model based on hydraulic radius theory had a better agreement with experimental values than the model based on drag theory, but the values were much higher than the experimental results, especially for higher porosity and higher pressure gradient.

Multipurpose nonwoven viscose/polypropylene fabrics: Effect of fabric characteristics on sorption and dielectric properties

“…The total porosity of the nonwoven fabrics obtained from viscose/polypropylene fiber blends was calculated by the equation: where δ is the nonwoven fabric density (g⋅cm −3 ) and ρ fm is the weight average density of fibers (g⋅cm −3 ). Nonwoven fabric density ( δ , g⋅cm −3 ) was calculated using the following equation: where M a is the weight of nonwoven fabrics (g⋅m −2 ), and T is the thickness of nonwoven fabrics (mm).…”

Enhancement of Hydrostatic Resistance and Mechanical Performance of Waterproof Breathable Laminated Fabrics

“…Air permeability is defined as the rate of air flow passing perpendicularly under a prescribed air pressure through a known area between the two surfaces of a material. Textest FX-3300 air permeability tester, which measures airflow rate under constant air pressure [19], was used to measure air permeability of the samples according to standard EN ISO 9237. Test area of the sample was 20 cm 2 , and air pressure difference between the two surfaces was kept at 200 Pa because of the layered structures of the fabric samples.…”

Comfort parameters of clothing woven fabrics in twill weave before and after thermal fixation of interlining

“…Budući da je propustljivost vazduha tekstilnih materijala, a time i tkanih struktura, primarno određena njihovom poroznošću, za ispitivane tkanine je izračunata poroznost uzoraka (P, %), defi nisana kao ukupna poroznost u tkanini (računajući pore između pređa i pore između vlakana unutar pređe), prema jednačini [30,31]:…”

“…Kod prvog uzorka je i posle termičkog fi ksiranja međupostave (uzorak 1M) registrovana statistički značajno veća propustljivost vazduha u odnosu na drugi uzorak (uzorak 2M), što je takođe potvrđeno t-testom (t 1M/2M =5,17 sa lica na naličje i t 1M/2M =5,30 sa naličja na lice materijala). Propustljivost vazduha oba ispitivana uzorka se smanjila posle termičkog fi ksiranja međupostave (tabela 2), što se može dovesti u vezu sa povećanjem debljine materijala, a što je u skladu sa rezultatima Zhu i saradnika [30]. Osim toga, tokom procesa termičkog fi ksiranja tkane međupostave na ispitivane tkanine došlo je do topljenja termoplastičnog vezivnog sredstva nanetog na međupostavu koje je prodrlo u strukturu tkanina (u makropore, kao i u pore između vlakana u pređi) što je svakako dovelo do smanjenja poroznosti novonastalih uzoraka 1M i 2M, u odnosu na polazne uzorke 1 i 2.…”